influence of steel composition on the mechanical...

INFLUENCE OF STEEL COMPOSITION ON THE MECHANICAL

PROPERTIES AND Zn-Mg-Al COATING LAYER ON THE CORROSION

RESISTANCE OF STEEL WIRE ROPES FOR OFFSHORE APPLICATIONS

MYUNG HYUN CHO

A thesis submitted in fulfilment of the

requirements for the award of the degree of

Doctor of Philosophy (Mechanical Engineering)

Faculty of Mechanical Engineering

Universiti Teknologi Malaysia

JUNE 2016

v

DDDDedicateedicateedicateedicatedddd to

My chairman, My family, My Supervisor

&

Kiswire Top Management

vi

ACKNOWLEDGEMENT

How fast time flies! Five years have been almost passed. I am coming to the

end of a road. I felt that I am not alone on this road, many people have been together

with me along this journey and I acknowledge their help.

I would like to express my deepest sense of obligation and gratitude to my

chairman, Mr. Hong Young Chul for giving me the opportunity to do this study and

all the moral support and expenses.

I would like to express my sincere appreciation to my thesis supervisor, Prof.

Dr. Esah bt Hamzah for her continous support, valuable advice and motivation

throughout the completion of this work . My gratitude also extended to my former

supervisor, Prof. Dr. Ali Ourdjini, OTTAWA University, Canada, for his

supporting , guidance and assitance in the Mg alloy zinc coating experiment aspects

of my research.

I extend my heartfelt thanks to CEO, Charles Lee, Scott Hong and Korean

staffs of KISWIRE SEA HQ for their constant encouragement, they have been my

finest balm during this journey.

My sincere appreciation also extends to my R&D Researchers, Mr. Faiq and

others who have provided assistance at various testings. I shall never forget the

endless encouragement and assistance they had provided.

Finally, I am very grateful to my wife and sons for their endless affection,

patience, interest and constant encouragement. There are still many people that I am

very grateful for their help and support thoughout this journey which I do not specify

here.

vi

ABSTRACT

Steel rope is generally used for mooring application. Recently, higher

strength and corrosion resistance are required to avoid the weight penalty with

increase of the sea-water depth in offshore oil production. This can be achieved by

increasing the carbon content and adding alloy elements in zinc coating. Three

objectives of the research were conducted as follows; to investigate the effect of

composition on strength and corrosion resistance of galvanized wire, to investigate

the degradation mechanism of high tensile strength (2,150 ~2,250MPa) galvanized

steel rope in sea-water and to develop a Zn-Al-Mg ternary alloy coating to enhance

the corrosion resistance of steel ropes. Microstructural characterisation on coated

steel wires was carried out using optical microscope, field emission scanning

electron microscope (FESEM) equipped with energy dispersive spectrometer (EDS)

and X-ray diffractometer (XRD). Both Tafel polarization and salt spray tests were

conducted to investigate the corrosion resistance of Zn-Mg-Al alloy coatings.

Torsion, fatigue and tensile tests were conducted. The best fatigue property was

obtained at 2,167MPa tensile strength. Tensile strength above 2,167MPa, fatigue and

torsion properties were reduced and the susceptibility to surface defect also was

increased during fatigue testing, by which cracks can be easily created and grown at

different planes at the same time. It is the main cause of fatigue degradation.

Degradation of mooring rope is caused by combination of fretting and corrosion

which normally occurs in wire rope assembly type known as Independent Wire Rope

Core (IWRC). Excellent corrosion resistance over 3,000 hours based on salt spray

test was obtained by addition of magnesium and aluminium elements in the range of

1.0~3.0wt% but no improvement for over 3wt% Mg, which might be attributed to

coarsening of the phase grains. The multi-layer coatings in which each layer consists

of several different alloy phases has an advantage because each phase has a unique

function and they exert their synergic functions in corrosion environment. As a

conclusion, applying Zn-Mg-Al coating to mooring rope improves life span of rope

due to reduced crack in the coating and excellent corrosion resistance.

vi

ABSTRAK

Tali keluli secara umumnya digunakan untuk aplikasi menambat. Mutakhir

ini, kekuatan yang tinggi dan rintangan terhadap kakisan adalah diperlukan untuk

mengelakkan penalti berat terhadap pertambahan kedalaman air laut pada

penghasilan minyak di luar pesisir pantai. Ini dapat dicapai dengan meningkatkan

kandungan karbon dan menambah unsur aloi dalam salutan zink. Tiga objektif kajian

yang telah dilaksanakan adalah seperti berikut; mengkaji kesan komposisi terhadap

kekuatan dan rintangan kakisan dawai tergalvani, mengkaji mekanisma degradasi

kekuatan tegangan tinggi (2,150 ~ 2,250 MPa) tali keluli tergalvani di dalam air laut

dan menghasilkan salutan aloi pertigaan Zn-Al-Mg untuk meningkatkan rintangan

kakisan terhadap tali keluli. Pencirian mikrostruktur pada dawai keluli tersalut telah

dilaksanakan dengan mengunakan mikroskop optik, mikroskop medan pancaran

elektron imbasan (FESEM) yang dilengkapi dengan spektrometer serakan tenaga

(EDS) serta pembelau sinar-X (XRD). Kedua-dua polarisasi Tafel dan ujian

semburan air garam telah dijalankan untuk mengkaji sifat rintangan kakisan salutan

aloi Zn-Mg-Al. Ujian kilasan dan tegangan telah dijalankan. Sifat kelesuan yang

paling tinggi dicatat pada 2,167 MPa. Kekuatan tegangan melebihi 2,167 MPa, sifat

kilasan dan lesu berkurang dan kerentanan terhadap kecacatan permukaan meningkat

apabila ujian kelesuan, di mana retak mudah terbentuk dan pada masa yang sama

merebak pada satah yang berbeza. Ini adalah faktor utama degradasi kelesuan.

Degradasi tali penambat adalah disebabkan kombinasi diantara perlagaan antara

dawai dan kakisan yang lazim berlaku pada jenis perhimpunan tali dawai dikenali

sebagai Independent Wire Rope Core (IWRC). Rintangan kakisan yang terbaik dapat

diperolehi pada jangka masa melebihi 3,000 jam berdasarkan kepada ujian semburan

garam dengan penambahan unsur magnesium dan aluminium dalam lingkungan

1.0~3.0% berat namun tiada penambahbaikan selepas melebihi 3% berat Mg,

mungkin disebabkan oleh pembesaran fasa bijian. Salutan pelbagai-lapisan yang

mana setiap lapisan mengandungi beberapa fasa aloi berbeza mempunyai kelebihan

kerana setiap fasa memiliki fungsi unik dan memberi fungsi sinergi di dalam

persekitaran kakisan. Kesimpulannya, mengaplikasikan salutan Zn-Mg-Al kepada

tali penambat dapat menambah baik jangka hayat tali disebabkan salutan mempunyai

keretakan yang lebih rendah dan rintangan kakisan yang lebih tinggi.

vii

TABLE OF CONTENTS

CHAPTER TITLE PAGE

TITLE i

DECLARATION ii

DEDICATION iii

ACKNOWLEDGEMENT iv

ABSTRACT v

ABSTRAK vi

TABLE OF CONTENTS vii

LIST OF TABLES xii

LIST OF FIGURES xiii

LIST OF ABBREVATIONS xxiii

1 INTRODUCTION 1

1.1 Background of the Research 1

1.2 Problem Statement 3

1.3 Objectives of the Research 4

1.4 Scope of Work 5

viii

2 LITERATURE REVIEW 6

2.1 Introduction 6

2.1.1 Steel Rope Manufacturing 6

2.1.2 Mooring System 8

2.2 Strengthening of Steel Wires 9

2.2.1 Influence of Alloying Elements on

Strengthening of High Carbon Steel

10

2.2.2 Influence of Microstructure on Strengthening

of High Carbon Steel

13

2.3 Fatigue Characteristic Behavior of Hyper-eutectic

Pearlitic Drawn Wires

14

2.3.1 Parameters Influencing Fatigue Property of

Drawn Wire

15

2.4 Mooring Steel Wire Rope Degradation Factors 22

2.4.1 Wire Rope Endurance in Sea Water 24

2.4.2 Parameters Influencing Fretting Wear 28

2.5 Improvement of Corrosion Resistance by Magnesium

Alloy Zinc Coating

30

2.5.1 Technology Trend 30

2.5.2 Morphology and Corrosion Behavior of Zn-

Mg-Al Coating According to Its Chemical

Composition

32

2.5.3 Effect of the Alloying Elements 40

2.6 Summary 41

3 METHODOLOGY 43

3.1 Introduction 43

3.2 The Effect of Chemical Composition on Strength and

Corrosion Resistance of Galvanized High Strength

Steel

47

3.2.1 Materials and Samples for Investigating The 48

ix

Effect of Chemical Composition on

Delamination and Zn-Fe Alloy Formation of

Galvanized Wire

3.2.2 Materials and Sample Preparation for

Investigating The Effect of Tensile Strengthon

Fatigue Life of Strand After Stranding Process

49

3.2.3 Materials and Samples for Investigating The

Effect of Zn-Fe Alloy layer on Corrosion

52

3.3 Degradation of Rope in Sea Water 53

3.4 Investigation on The Corrosion Resistance of Steel

Wire in Sea Water by Adding Alloying Elements

into Molten Zinc Bath

56

3.4.1 Materials and Samples Preparation 56

3.4.2 Melting Pot Temperature Control 58

3.5 Characterization Techniques 59

3.5.1 Microstructure and EDX Chemical Analysis 59

3.5.2 Inductively Coupled Plasma Mass

Spectrometry (ICP-MS) and Inductively

Coupled Plasma Emission Spectrometry

(ICP-OES) Chemical Analysis

61

3.5.3 Determination of Mechanical Properties 62

3.5.3.1 Torsion and Tensile Test 62

3.5.3.2 Fatigue Test 64

3.5.4 Corrosion Test 66

3.5.4.1 Corrosion of Rope in Sea-Water 66

3.5.4.2 Salt Spray Corrosion Test 69

3.5.4.3 Electrochemical Test

(Polarization/Tafel Curve)

71

4 RESULTS AND DISCUSSION 74

4.1 Introduction 74

4.2 The Effect of Chemical Composition of Steel on 75

x

Strength and Corrosion Resistance of Galvanized

Steel

4.2.1 The Effect of Chemical Composition on

Delamination and Zn-Fe Alloy Formation of

Galvanized Steel Wire

75

4.2.2 The Effect of Tensile Strength on the fatigue

Life of Strand After Stranding Process

85

4.2.2.1 Fatigue Effect 85

4.2.2.2 Fracture Morphology Behaviour 88

4.2.3 The Effect of Zn-Fe Alloy Layer Thickness on

The Corrosion Resistance of Galvanized Wire

104

4.3.4 Summary 113

4.3 Degradation of Steel Rope in Seawater 115

4.3.1 Appearance of Steel Rope Used for 3.5 Years

in Deep Sea Mooring Applications

115

4.3.2 Corrosion Rate of Wires According to Wire

Position

119

4.3.3 Corrosion Morphology of Wires as Function

of the Wire Position

121

4.3.4 Summary 136

4.4 Effect of Alloy Coating Composition on the

Corrosion Resistance of Zn-Mg-Al Coatings

138

4.4.1 Morphology Behavior of Alloy Coating

According to Their Chemical Compositions

139

4.4.1.1 Zn – 0.5wt % Mg – 0.5wt% Al Alloy

Coating

139


Coating

146


Coating

150


Coating

155

4.4.1.5 Z Zn – 3.0wt % Mg – 6.0wt% Al Alloy 160

xi

Coating


Coating

166

4.4.1.7 Morphology of Alloy Melting Pot

Ingot

170

4.4.1.8 Summary of Morphology of Alloy

Coatings

175

4.4.2 Corrosion Behaviour of Alloy Coating

According to Their Coating Chemical

Composition

176

4.4.2.1 Corrosion Test (Polarization/Tafel) and

Salt Spray Test

176

4.4.2.2 Morphology of the Corrosion Product 177

4.4.2.3 Morphology of Coated Steel Cross

Sections after Salt Spray Test

184

4.4.2.4 Morphology of Coating of steel wire

drawn after coating

192

4.4.3 Summary 194

5 CONCLUSION 197

5.1 Conclusion 197

5.2 Recommendation for the Future Work 199

REFERENCES 200

xii

LIST OF TABLES

TABLE NO. TITLE PAGE

2.1 Properties of inter-metallic alloy phases in hot-dip

galvanizing

18

2.2 The rate of Zinc dissolution in tropical seas, in most of

South East Asian countries

23

2.3 Suggestions provided by API and DNV for service life in

years, based on various rope constructions

23

2.4 Fretting-corrosion wear volume measurements for

galvanized and bright wires in air sea water

29

2.5 Fretting corrosion wear volume measurement for bright

wires in air and sea water, with applied potential

29

2.6 Electro polarization test results of coatings having different

alloy contents. Testing condition: 3.5% NaCl solution of pH

7.5, Icorr and Ecorr values by Tafel plot and the corrosion rate

(mpy)

39

3.1 Chemical compositions of steels used to investigate the

effect of steel composition on mechanical properties of

galvanized drawn wires

49

3.2 Materials and loading conditions for fatigue test of strands

according to tensile strength grades

50

3.3 Materials with different Zn-Fe alloy thickness 52

3.4 Tensile strength and diameter of the wires inside rope 55

3.5 Composition of Zn-Mg-Al alloy coating samples 57

4.1 Work hardening and lamellar spacing versus chemical

composition of steels

78

xiii

LIST OF FIGURES

FIGURE NO. TITLE PAGE

2.1 Schematic showing how ropes are constructed: (a)

Sheathed spiral strand and (b) 6 strand rope

7

2.2 Illustration of a turret anchored Floating Production,

Storage and Offloading (FPSO). Courtesy of APL/Axis

9

2.3 Effect of Si content on tensile strength of lead patented

wires and Stelmor-cooled wire rods

11

2.4 Torsion fracture types and their evaluation grades 16

2.5 Delamination of torsion testing 16

2.6 Alloy phases of hot-dip galvanizing coating 18

2.7 A schematic drawing of Fe-Zn alloy phase formation in

pure molten Zn bath

19

2.8 Effect of immersion time on Iron loss as a function of

percentage Si content

21

2.9 The rates of relative dissolution of galvanized coating from

steel wire continuously wetted with water, normalized to 1

at 5° C

22

2.10 Histogram showing the amount of remaining zinc coating

in the individual wires of a 70 mm diameter six strand rope

(6x37+IWRC) after 12 years of marine exposure in the

splash zone (unloaded)

25

2.11 Histogram showing the amount of remaining zinc coating

on the 19 individual wires of a 89 mm diameter six strand

rope (6x49+IWRC) after 10 years of marine exposure as a

catenary (loaded)

26

xiv

2.12 Summary of single wire tensile fatigue tests from AERE

study

27

2.13 Cross sectional SEM and EDX images of coating layer in

Zn-Al-Mg alloy coating (11wt%Al,3wt%Mg,0.2wt%Si ): a)

SEM image, b) Al, c) Mg, d) Zn

33

2.14 Scanning electron microscope images of Zn-5wt%Al-

0.5wt%Mg -0.08wt%Si coating and EDX analysis

34

2.15 SEM cross-sectional micrographs of Zn-2wt%Al-2wt%Mg

coated steel sheet produced by hot-dipping

35

2.16 Surface morphology of coating and EDX analysis (wt. %):

(a) Zn-2.5 Mg, (b) Zn-0.5Mg, (c) Zn-0.5Mg-0.25Al

37

2.17 SEM microstructures and EDX analyses for three coating

samples produced by dipping for 10 seconds in molten bath

at 420 °C

38

2.18 SEM microstructures of ZnAlMgSi coating after 28 days of

exposure to humid air

40

3.1 Flow chart of research methodology : (a) Phase 1, (b) Phase

2, (c) Phase 3

46

3.2 (a) Drawing machine. (b) Stranding machine – Tubular-

Type

51

3.3 Cross-sectional view of the rope 54

3.4 Whole process of first and second hot-dip galvanizing 57

3.5 Melting furnace 58

3.6 Torsion test: (a) setup specimen in torsion tester, (b)

delamination measuring device

63

3.7 Set up strand specimen in Instron tension-tension fatigue

testing machine

65

3.8 Socketing of sample for tension-tension fatigue testing 65

3.9 Appearance of rope after being used for 3.5 years for the

mooring application

68

3.10 Wires after rope was dismantled 68

3.11 Salt spray testing; (a) salt spray test machine, (b) specimen

position in the chamber

70

xv

3.12 Specimen for electrochemical polarization test and

impedance spectra test: (a) schematic drawing (b) actual

specimen

72

3.13 The complete electrochemical corrosion test: (a) three

electrode electrochemical test cell (b) complete set-up

72

3.14 Typical polarization/Tafel curve 73

4.1 True stress-true strain plot showing work hardening rates for

steels with different carbon content

77

4.2 FESEM microstructures of (a) 97B DLP (0.043 µm) and (b)

98B LP (0.061 µm) with different lamellar spacing

77

4.3 Torsion values versus strain for four steels: 87B DLP

13mm, 92BLP 12mm, 97B DLP 11.5mm, 98B LP 12mm

79

4.4 Delamination of drawn wire 4.30mm for 97B DLP 11.5mm:

(a) whole fracture appearance, (b) cross-section surface of

fracture, (c) enlargement of (b)

80

4.5 Torque as a function of elapsed time 81

4.6 Micro-crack formations due to gamma layer of cold drawn

wire in 92B LP steel, (a) micro-crack in the surface of steel,

(b) enlargement of (a)

82

4.7 Crack propagation morphology of delamination during

drawing of 98B-0.60% Si: (a) whole appearance of torsion

fracture, (b) opposite part of (a), (c) enlargement of (b)

indicated by arrow

83

4.8 Alloy layer thickness as function of Si% in: (a) 97B-0.2% Si

and (c) 92B-1.3% Si, (b) EDX line scan analysis of (a), (d)

EDX line scan analysis of (c)

84

4.9 Tension-tension fatigue and torsion value according to

tensile strength

86

4.10 The effect of surface defect on tension-tension fatigue

according to tensile strength

87

4.11 Fractography of failed inner wire during tension-tension

fatigue testing of strand with 2,108 MPa (Longer fatigue:

558,432 cycles): (a) whole fracture surface, (b) whole

89

xvi

fracture surface at different angle, (c) enlargement of area,

B of (a), and (d) enlargement of area, A of (a)

4.12 Fracture surfaces of failed outer wire during tension-tension

fatigue testing of strand with 2,108 MPa (Longer fatigue:

558,432 cycles) : (a) fracture mode, (b) fracture mode of

matching part of broken wire, (c) enlargement of fatigue

fracture propagation in zone, A of (a), and (d) enlargement

of fatigue fracture propagation in zone, B of (a)

91

4.13 Fractography of outer wire fractured during tension-tension

fatigue testing of strand with 2,108MPa (Longer fatigue:

446,760 cycles) : (a) Whole fracture surface, (b) micro

crack on the longitudinal surface of the crack initiation site,

(c) enlargement of the fatigue fracture propagation in the

fracture initial part (e), (d) enlargement of surface crack (e),

and (e) fracture initial part in the micro-crack area

93

4.14 Fracture surfaces of inner wire fractured during tension-

tension fatigue testing of strand with 2,167 MPa (Longer

fatigue: 599,144 cycles): (a) whole fracture surface, (b)

enlargement of window area in a, and (c) enlargement of

window area in b

95

4.15 Fracture surfaces of outer wire fractured during T-T fatigue

testing of strand with 2,167 MPa (Longer fatigue: 599,144

cycles): (a) whole fracture surface, (b) whole fracture

surface of other part, (c) enlargement of red window area in

A, and (d) enlargement of yellow window area in B

96

4.16 Fracture of outer wire fractured during T-T fatigue testing

of strand with 2,167 MPa (shorter fatigue: 164,540 cycles):

(a) shear fracture of the broken wire, (b) enlargement of (a),

(c) shear fracture of another broken wire, and (d)

enlargement of the red circle of (c)

97


testing of strand sample I with 2,236 MPa (shorter fatigue:

221,043 cycles): (a) enlargement of zone, A of (b), (b)

99

xvii

whole fracture surface, (c) enlargement of zone, B of (b),

(d) whole fracture surface in another direction, (e)

enlargement of circle of (f), and (f) enlargement of circle of

(d)


testing of strand with 2,236 MPa: shorter fatigue: 221,043

cycles: (a) fatigue crack - enlargement of zone, A of (b), (b)

whole fracture surface, (c) surface crack - enlargement of

zone, B of (b), (d) propagation of crack from Zn alloy to

steel matrix - enlargement of yellow circle of (d), (e)whole

fracture surface in another direction, and (f) fatigue crack -

enlargement of red circle of (f)

101

4.19 Fracture morphology behaviors of outer wires according to

tensile strength during T-T fatigue testing of strand: (a)

2,108 MPa, (b) 2,167 MPa, (c) 2,236 MPa: multi-place

fatigue cracks, and (d) 2,236 MPa: different level cracks

103

4.20 Salt spray hours vs. alloy layer thickness ratio (%) 105

4.21 Cross-section of the Zn coating of the sample without

cracks after 310 hours exposure to the salt spray test

106

4.22 Behavior of corrosion progress of a sample with a crack

within the coating layer after 310 hours exposure to the salt

spray test

106

4.23 Crack propagation behavior of Zn coating from galvanized

rod to drawing: (a) galvanized rod 11.5mm, (b) enlargement

of alloy layer of (a), (c) 5.14mm drawn wire (Reduction:

80%), (d) 4.71m drawn wire (Reduction: 83%), and (e)

4.31mm drawn wire (Reduction: 86%)

108

4.24 Corrosion behavior versus crack size of Zn coating after 310

hours salt spray test for samples: K, L, M, N, O, and P

110

4.25 Effect of heat treatment on corrosion behavior versus crack

size of Zn coating after 310 hours salt spray test

112

4.26 EDX spectrum peaks of crack surface of sample N 113

4.27 Appearance of steel rope after being used for 3.5 years: (a) 117

xviii

construction of rope, (b) whole appearance of rope, (c)

appearance of IWRC, and (d) appearance of SC and RC

after dismantling

4.28 Appearance of the wire of steel rope strand after being used

for 3.5 years; (a) appearance of wires of S1 and S2, (b)

appearance of wires of S3, (c) appearance of wires of S4,

(d) appearance of wires of S5, and (e) appearance of wires

of S6

118

4.29 Corrosion rate of steel rope as a function of wire position

after being used for 3.5 years

120

4.30 Chloride content of wire surface according to wire position

after being used for 3.5 years

120

4.31 Cross-sections of wires in SC and RC strands after service

for 3.5 years

123

4.32 Cross-sections of R1 wire of IWRC after service for 3.5

years: (a) corrosion progressed along the interface between

the Zn-Fe alloy layer and substrate steel base, (b) corrosion

propagated inside the steel matrix resulting in corrosion pits,

(c) all Zn coatings were removed due to corrosion, and (d)

some surface areas still had Zn coating on the surface

125

4.33 Contact part of corrosion of R1 wire of IWRC after service

for 3.5 years

126

4.34 Cross-sections of S4 wires of IWRC after service for 3.5

years

127

4.35 FESEM image of contact part of corrosion of S4 wire of

IWRC after service for 3.5 years: (a) crevice corrosion and

pitting, (b) crevice corrosion and pitting, and (c) severe

pitting

128

4.36 Cross-section of wires of the rope strand after service for

3.5 years

129

4.37 FESEM images of corrosion morphology of wire rope

strands after service for 3.5 years

130

4.38 FESEM image of the cross-section of fretting of R1 of 131

xix

IWRC RC

4.39 FESEM image of cross-section of–0.5wt%Mg–0.5wt%Al

alloy coating sample

140

4.40 FESEM micrograph and EDX results of the first layer of Zn

– 0.5wt%Mg – 0.5wt% Al alloy coating

141

4.41 FESEM micrograph and EDX results of the second layer of

Zn – 0.5wt%Mg – 0.5wt% Al alloy coating

142

4.42 FESEM micrograph of Zn-0.5wt% Mg-0.5wt% Al alloy

coating after reducing the alloy thickness of the first pure

galvanizing process

143

4.43 FESEM micrograph and EDX results of third layer of Zn-

0.5wt% Mg-0.5%wt Al alloy coating

144

4.44 FESEM image and EDX analysis of surface of Zn-0.5wt%

Mg-0.5wt% Al alloy coating

145

4.45 FESEM image of surface of Zn-1.0wt% Mg-1.0wt% Al

alloy coating

146

4.46 FESEM micrograph and EDX results of first layer of Zn-

1.0wt% Mg-1.0wt% Al alloy coating

147

4.47 FESEM image and EDX results of second layer of Zn-


148

4.48 FESEM image and EDX results of third layer of Zn-1.0wt%


149

4.49 FESEM image and EDX results of surface of Zn-1.0wt%


150

4.50 FESEM micrograph of Zn-2.0wt% Mg-2.0wt% Al alloy

coating

151

4.51 FESEM of the first layer of Zn-2.0wt% Mg-2.0wt% Al

alloy coating and EDX results

151

4.52 FESEM image and EDX analysis of second layer of Zn-


152

4.53 FESEM image and EDX results of third layer of Zn-2.0wt%


153

4.54 FESEM image and EDX results of surface layer of Zn- 154

xx


4.55 FESEM image of surface layer of Zn-3.0wt% Mg-2.0wt%

Al alloy coating

155

4.56 FESEM image and EDX results of first layer of Zn-3.0wt%


156


3.0wt% Mg-2.0wt% Al alloy coating: (a) second layer, (b)

enlargement of second layer of (a) and EDX analysis

157

4.58 FESEM image and EDX results of the third layer of the Zn-

3.0wt% Mg-2.0wt% Al alloy coating: (a)&(b) third layer,

(c) enlargement of third layer of (a) and EDX results

159

4.59 FESEM image and EDX results of the fourth layer of the

Zn-3.0wt% Mg-2.0wt% Al alloy coating

160

4.60 FESEM image of the surface layer of Zn-3.0wt% Mg-

6.0wt% Al alloy coating

161



162



163

4.63 FESEM images and EDX results of the third layer of the

Zn-3.0wt% Mg-6.0wt% Al alloy coating: (a) third layer and

EDX analysis, and (b) magnified view of the third layer

164

4.64 FESEM image and EDX results of fourth layer of Zn-


165

4.65 FESEM image of surface layer of Zn-5.0wt% Mg-5.0wt%

Al alloy coating

166



167



168

4.68 FESEM image of the third layer of the Zn-5.0wt% Mg-

5.0wt% Al alloy coating

169

4.69 FESEM image of fourth layer of Zn-5.0wt% Mg-5.0wt% Al 170

xxi

alloy coating

4.70 FESEM micrographs of Zn-0.5wt% Mg-0.5wt% Al ingot

(a) whole phases, (b) magnified view of Eutectic binary

phase

171

4.71 FESEM microstructure of alloy ingot: (a) Zn-1.0wt% Mg-

1.0wt% Al ingot, (b) Zn-2.0wt% Mg-2.0wt% Al ingot, (c)

Zn-2.0wt% Mg-3.0wt% Al ingot

173

4.72 FESEM micrograph of Zn-5.0wt% Mg-5.0wt% Al ingot (a)

Whole phases (b) magnified view of ternary eutectic phase

174

4.73 FESEM micrograph of Zn-3.0wt% Mg-6.0wt% Al ingot 175

4.74 Corrosion rate versus magnesium and aluminum content of

alloy coating (Polarization/Tafel)

177

4.75 FESEM micrograph and EDX results of corrosion product

of pure zinc coating after 266 hours salt spray test

179

4.76 FESEM micrograph and EDX analysis of corrosion product

of Zn-Al coating after 720 hours salt spray test

180

4.77 FESEM micrograph and EDX results of Zn-0.5wt% Mg –

0.5wt% Al alloy coating before salt spray test

182

4.78 FESEM micrographs of corrosion products of Zn-0.5wt%

Mg-0.5wt% Al alloy coating after 3,144 hours exposure to

salt spray test

183

4.79 XRD analysis of corrosion product of Zn-0.5wt% Mg–

0.5wt% Al alloy coating after 3,144 hours exposure salt

spray test

184

4.80 FESEM microstructure of coating of Zn-0.5wt% Mg –

0.5wt% Al alloy coating before and after 3,144 hours salt

spray test

185

4.81 FESEM micrograph of the whole layer containing the thick

part of the Zn-0.5wt% Mg – 0.5wt% Al alloy coating after

3,144 hours exposure to salt spray testing

187

4.82 FESEM micrograph and EDX results of the top and middle

layers of the thick coating of the Zn-0.5wt% Mg–0.5wt% Al

alloy coating after 3,144 hours of salt spray +2 years

188

xxii

atmosphere exposure

4.83 FESEM micrograph and EDX analysis of first layer of thick

coating of Zn-0.5wt% Mg–0.5wt% Al alloy coating after

3144 hours exposure in salt spray +2years atmosphere

exposure

189

4.84 FESEM micrograph and EDX results of first layer of Zn-

0.5wt% Mg – 0.5wt% Al alloy coating after 3144 hours salt

spray +2years atmosphere exposure

190

4.85 FESEM microstructure of 3.83 mm wire drawn after pure

Zn coating

193

4.86 FESEM microstructure of 3.83 mm wire drawn after

the Zn-0.5wt% Mg – 0.5wt% Al alloy coating

193

xxiii

LIST OF ABBREVATIONS

CPS - Counts per second

CR - Corrosion rate

DLP - Direct in line patenting

EG - Electro galvanized

EDX - Energy Dispersive X-Ray Spectroscopy analyzer

EIS - Impedance spectra test

FESEM - Field Emission Scanning Electron Microscope

FPSO - Floating production storage and offloading

HDG - Hot dip galvanizing

HDPE - High density polyethylene

ICP-MS - Inductively Coupled Plasma Mass Spectrometry

ICP-OES - Inductively Coupled Plasma Emission Spectrometry

IWRC - Independent Wire Rope Core

LPD - Lead patenting process

mm - Millimeter

mm/y - Millimeter per year

N/mm2 - Newton per millimeter square

PVD - Physical vapour deposition

RC - Rope core (strand of IWRC)

SC - Core strand

SCE - Saturated calomel electrode

SPM - Single point moorings

T-T fatigue - Tension-tension fatigue

XRD - X-ray diffraction

α - Entrance angle

CHAPTER 1

INTRODUCTION

1.1 Background of the Research

The global offshore oil industry is expected to continue to increase in the

coming years, driven by the depleting onshore reserves and the discovery of new

large offshore reserves. Oil production in deep and ultra-deep waters has

significantly helped to advance new technologies. However, in exploring oil at

depths beyond 1500 meters, steel wire ropes experience many challenges which stem

from the sheer weight of the mooring system [1]. As water depth increases,

conventional all-steel spread mooring systems show a number of limitations, both in

operation and on the environment [2]. Such limitations include a lower restoring

efficiency, high proportion of tether strength consumed by the vertical components of

line tension, reduced pay-load of the vessel, and large mooring radius and sea-floor

footprint [2]. The weight penalty of steel wire also increases rapidly with water depth

and has become a significant cost driver for water depths beyond 2000 meters [3].

2

The obvious solution to these limitations is to avoid the weight penalty. There

are two possible ways to achieve this: (1) use lightweight materials such as fiber

ropes, or (2) increase the strength of steel rope so that it can be made thinner. There

are several problems that must be solved if fiber rope is to be used as a substitute for

steel wire rope: low axial stiffness that causes rope elongation with load, low

adhesive wear and tear resistance, low fatigue life when subjected to constant cyclic

bending due to damage occurring during heave compensation modes, internal heat

buildup, very low and variable coefficient of friction due to rope coating,

contamination and temperature. Therefore, steel wire rope is still effective for use in

mooring line components in deep water. However, further strengthening of steel wire

is required to overcome the weight penalty. Strengthening of steel wire can be

achieved by increasing carbon content, adding alloying elements and increasing cold

work [4-11]. A considerable amount of work has been carried out on micro-alloyed

steel in the past years, particularly involving chromium, manganese and

molybdenum additions [4-9]. The use of carbon contents up to 0.92% has been

shown as having potential for enhancing the strength of rods for roping applications

[10-11]. However, little work has been done towards improving the fatigue life and

corrosion resistance of steel wire ropes for offshore industry having carbon contents

higher than 0.92%. One of the fundamental problems is that there is the limit to

increase the strength of steel wire because the strength of the patented wire is

increased, but drawing amount is reduced with increasing carbon content. Another

problem is that it is difficult to meet the fatigue characteristics due to the

embrittlement that originates from cementite dissolution. Furthermore, the

mechanism of embrittlement is still not clear, since the mechanism of cementite

decomposition has been discussed without a common consensus being reached [12].

In the process of strengthening, the marine environmental factors should also

be considered because the effect of the marine environment on the fatigue life of the

ropes increases rapidly with the depth of seawater. Moreover, higher tensile strength

steels are more susceptible to the environment [13, 15]. Steel wire rope suffer

degradation by stress corrosion and fretting, particularly ropes used in mooring at sea.

Fretting can be exacerbated not only by the presence of such an aggressive

3

environment such as seawater, but also by the continuous cyclic loading through

wave movement over the length of the rope during its entire lifetime [14]. These

factors result in a significant reduction in the life of the ropes. Thus, the challenge is

to develop ropes with increased strength, and at the same time to reduce the harmful

effects of environmental factors.

In the present research, an investigation has been conducted to determine the

types of degradation that may occur when high strength steel ropes are used for

mooring lines, and to explore a new coating technology and steel strengthening

process to overcome these degradations.

1.2 Problem Statement

To fulfill the increased demand in the mooring application, new technology

development should be made in three areas: high strengthening technology, good

fatigue property in high strength steels, and excellent corrosion resistant coating

technology. However, several problems associated with these developments exist:

a) Since the effect of the marine environment on the fatigue life of ropes

increases rapidly with the depth of seawater, higher tensile strength steels have a

shorter life span, owing to their increased susceptibility to the environment. The

mechanism is still not clear and there is no method to date on how to solve such a

problem.

b) Steel wire rope is greatly affected by fretting-induced corrosion, which

becomes more severe with increasing sea water depth. However, there is a lack of

4

understanding on the effect of increasing the tensile strength on fretting-induced

corrosion and also on the methods to reduce this fretting harmful effect.

c) It is well-known that anti-corrosion products contribute to corrosion

inhibition, but in the case of severe fretting, their role is reduced because the anti-

corrosion material is easily removed. Until today, there is no research on how to

reduce this fretting harmful effect, or development of a new coating technology to

produce tough anti-corrosion products having high fretting resistance with increased

exposure to sea water.

d) It is well established that the life span of mooring ropes is primarily

dependent on the corrosion resistance of the zinc coating, but very few attempts were

made to develop a new coating capable of increasing the corrosion resistance of steel

wire ropes. This research is aimed to develop high tensile steel rope (2,150-2,250

MPa) with good corrosion resistance.

1.3 Objectives of the Research

To meet the current technology trend of offshore oil and gas production

facilities, development of ropes having lighter characteristics and longer life span is

required.

Therefore, the main objectives of this research are to develop steel ropes with

high tensile strength and excellent corrosion resistance. The specific objectives are:

1. To investigate the effect of composition on strength and corrosion

resistance of galvanized wire.

2. To investigate the degradation mechanism of high tensile strength (2,150 -

5

2,250 MPa) galvanized steel rope in sea water.

3. To develop a Zn-Al-Mg ternary alloy coating to enhance the corrosion

resistance (3,000 salt spray hours) of steel ropes.

1.4 Scope of Work

In order to increase the strength of steel wires, used in the oil and gas

industries, above 2,150 MPa and corrosion resistance over 3,000 salt spray hours, the

study concentrates mainly on the following:

1. Enhancing the fatigue property and corrosion resistance of galvanized

steel wire through control of steel chemical composition by varying the carbon

content (0.87-0.98wt%) and alloying elements of Cr (0.58-0.60wt%) and Si

(0.2~1.3wt%). This phase of research focuses on investigating:

a) Tensile strength, torsion and delamination of galvanized steel wire

b) Fatigue property and fracture behaviour of galvanized steel strand

c) Formation of Zn-Fe alloy layer during hot dip galvanizing and its effects

on the corrosion resistance of steel wire

2. Degradation mechanism of galvanized steel rope in sea water. This phase

consists of examining:

a) The effect of fretting and contact pressure among wires on the corrosion

behavior of exposed steel ropes

b) The corrosion behaviour based on wire position in the rope

3. Corrosion protection of rope in sea water by using newly developed zinc

alloy coating. This phase of research looks at:

a) The effects of Mg (0.5-5.0wt%) and Al (0.5-6.0wt%) contents on coating

microstructure

b) The effects of Mg and Al contents in the Zn alloy coating on the

corrosion behaviour and corrosion product characteristics

199

process, (c) corrosion product having good adhesion, which improves resistance

against fretting.

7. The lowest corrosion rate was obtained in the Zn-Mg-Al alloy coating

having 1.0~3.0wt% Mg and Al content. Even by addition of a small amount of Mg

and Al by 0.5wt%, the corrosion resistance, similar to the Zn-3.0wt%Mg-6.0wt%Al

alloy coating was obtained. Over that wt.%, the improvement effect of corrosion

resistance was not observed. The Zn-0.5wt% Mg-0.5wt% Al coating had an excellent

corrosion resistance (3,144 hours in salt spray), which was 12 times higher than the

pure Zn coating. It might be attributed to simonkolleite (Zn5 (OH)8Cl2 • H2O) found

on the surface as the main element of the corrosion product.

8. The Zn-Mg-Al Alloy coating produced by the two-step galvanizing

processes had very good corrosion resistance and fretting resistance due to the

following reasons: (a) multi-layers have several different alloy phases. These alloy

phases exert a synergistic effect in improving corrosion and fretting resistance, and

(b) no cracks inside the coating during the coating and drawing process.

5.2 Recommendation for Future Work

As described previously, since rope degradation was the dominating factor for

mooring, caused by fretting and corrosion, the investigation of the Zn-Al-Mg alloy

coated rope life span is required.

200

REFERENCES

1. Klaoudatos, L., Station Keeping for Deepwater Mobile Offshore Drilling

Units: An Economic and Operational Perspective. 2006: Erasmus University.

2. Del Vecchio, C., et al., Deep Water Mooring Systems Using Fiber Ropes.

Composite Materials for Offshore Operations, 1999. 2: p. 255-264.

3. Torben, S., et al., Fiber Rope Deployment System And Rope Management

Process, in The Eighteenth International Offshore and Polar Engineering

Conference. 2008, International Society of Offshore and Polar Engineers:

Vancouver, Canada.

4. Gh.Ali Nematollahi, Multiscale description of carbon-supersaturated ferrite

in severely drawn pearlitic wires. Actra Materialia, 2016. 111 : p.321-334.

5. Xiaodan Zhang, Andy Godfrey,Microstructure and strengthening mechansim

in cold-drawn pearlitic steel wire. Actra Materialia, 2011. 59: p.3422-3430.

6. Franklin, J., et al., Heat Treatment and Alloying of Drawn Wires. Wire

Industry, 1980. 47(563): p. 967-972.

7. Nishimura, T., T. Fujiwara, and Y. Tanaka, Multi-Wire Electrical Discharge

Slicing for Silicon Carbide. Wire Journal, 1980. 13(10).

8. Mikulec, Z., Drawing of Rapidly-Cooled Wire Microalloyed With Vanadium.

Hutnik(Prague), 1980. 30(5): p. 189-193.

9. Mazzucato, F., A. Mascanzoni, and A. Guerrieri, Effects of manganese,

chromium, and molybdenum on the isothermal transformation of austenite in

eutectoid steels. Wire J. International, 1982. 15(10): p. 74–79.

10. Stacey, A.G., Pearlitic Steels with Si and V Additions. Met. & Mat. Trans. A,

1987. 3: p. 706-711.

11. A, Lamontagne,V. Massardier,Evolution of carbon distribution and

mechanical properties during the static strain ageing of heavily drawn

pearlitic steel wires. Material Science & Engineering, 2016, A 667: p.

115-124

12. Takahashi, J., et al., Change in carbon state by low-temperature aging in

201

heavily drawn pearlitic steel wires. Acta Materialia, 2012. 60(1): p. 387-395.

13. K.j. Miller and R. Akid, The application of microstructural fracture

mechanics to various metal surface states. Material Science, 1997. 33(1): p.

1-19.

14. Chaplin, C., 33rd

Annual Offshore Technology Conference (OTC) May 2000.

12173 ; Vol 2, p. 837-844.

15. Chaplin, C. and A. Potts, Wire rope offshore–a critical review of wire rope

endurance research affecting offshore applications-Offshore Technology

Report OTH 91 341. 1991, HMSO UK.

16. Xiaohua Hu, Paul Van Houtte and Martin Liebeherr, Modeling work

hardening of pearlitic steels by phenomenological and Taylor-type

micromechanical models. Actra Materialia, 2006, volume 54, issue 4 : p.

1029-1040.

17. Europe, N.D., Floating production system JIP FPS mooring integrity. 2006,

Research report 444 prepared for the Health and Safety Executive (HSE).

18. Toshihiko Takahashi, Strengthening of steel wire for tire cord.Nippon steel

technical report , 1995. No.64: p. 45-499.

19. Shipley, E., High-Strength Steel Wire. High Strength Steels, 1962: p. 93-99.

20. Leslie, W. and G. Rauch, Precipitation of carbides in low-carbon Fe-AI-C

alloys. Metallurgical Transactions A, 1978. 9(3): p. 343-349.

21. Han, K., G. Smith, and D. Edmonds, Pearlite phase transformation in Si and

V steel. Metallurgical and Materials Transactions A, 1995. 26(7): p. 1617-

1631.

22. Kaiso, M., et al., Mechanical Properties of Drawn Hypereutectoid Steel Wires.

Wire Journal International, 2002. 35(2): p. 116-121

23. Ochiai, I., et al., Direct-Patented High-Strength Steel Wire Rod Strengthened

by Silicon. Wire Journal International 1933: p. 72-85.

24. Tashiro, H., et al., Alloying effect on the Strength of Directly Annealed Steel

Wire rods. Transactions ISIJ, 1988. 28: p. 29.

25. Han, K., et al., Effects of vanadium additions on microstructure and hardness

of hypereutectoid pearlitic steels. Materials Science and Engineering: A, 1995.

190(1): p. 207-214.

26. Nicholson, M., Solubility of boron in Fe3C and variation of saturation

202

magnetization, Curie temperature, and lattice parameter of Fe3 (C, B) with

composition. Trans-AIME (J. Metals), 1957. 209: p. 1-6.

27. Taleff, E.M., et al., Pearlite in ultrahigh carbon steels: Heat treatments and

mechanical properties. Metallurgical and Materials Transactions A, 1996.

27(1): p. 111-118.

28. Embury, J. and R. Fisher, The structure and properties of drawn pearlite.

Acta Metallurgica, 1966. 14(2): p. 147-159.

29. Dewey, M. and G. Briers, Structure of heavily cold drawn eutectoid steel.

Iron Steel Inst J, 1966. 204(2): p. 102-103.

30. Puttick, V., The Structure, Deformation and Fracture of Perlite. J. Iron Steel

Inst, 1957. 185(2): p. 161-176.

31. Fickering, F.B., Carbide precipitates in steels. Iron & Steel, 1965. 38: p. 110.

32. Takahashi, T. and M. Nagumo, Flow stress and work-hardening of pearlitic

steel. Transactions of the Japan Institute of Metals, 1970. 11(2): p. 113-119.

33. Kaldor, M., About the deformation of pearlite. Acta Metallurgica, 1962. 10(9):

p. 887.

34. Langford, G. and M. Cohen, Strain hardening of iron by severe plastic

deformation. ASM Trans Quart, 1969. 62(3): p. 623-638.

35. Lee, S., D. Ko, and B. Kim, Pass schedule of wire drawing process to prevent

delamination for high strength steel cord wire. Materials & Design, 2009.

30(8): p. 2919-2927.

36. Nishida, S., A. Yoshie, and M. Imagumbai, Work Hardening of

Hypereutectoid and Eutectoid Steels during Drawing. ISIJ international, 1998.

38(2): p. 177-186.

37. Maruyama, N., T. Tarui, and H. Tashiro, Atom probe study on the ductility of

drawn pearlitic steels. Scripta materialia, 2002. 46(8): p. 599-603.

38. Languillaume, J., G. Kapelski, and B. Baudelet, Cementite dissolution in

heavily cold drawn pearlitic steel wires. Acta Materialia, 1997. 45(3): p.

1201-1212.

39 Watté, P., et al., Strain ageing in heavily drawn eutectoid steel wires. Scripta

materialia, 1996. 34(1): p. 89-95.

40. Hono, K., et al., Cementite decomposition in heavily drawn pearlite steel wire.

Scripta materialia, 2001. 44(6): p. 977-983.

203

41. Gridnev, V. and V. Gavrilyuk, Cementite Decomposition in Steel During

Plastic Deformation.(Review). Phys. Met.(USSR), 1982. 4(3): p. 531-551.

42. Bushan (2011) Continuous Hot-Dip Galvanizing versus General (Batch)

Galvanizing. Galv InfoNote 2-3.

43. Skenazi, A.F., et al. Zinc Coated Steels. in Proceedings of the 1st

International Conference on Zinc Coated Steel. 1985. Munich, London: Zinc

Development Association.

44. Jordan, C. and A. Marder, Fe-Zn phase formation in interstitial-free steels

hot-dip galvanized at 450° C: Part I 0.00 wt% Al-Zn baths. Journal of

Materials Science, 1997. 32(21): p. 5593-5602.

45. Sandelin, R.W., Galvanizing Characteristics of Different Types of Steels. Wire

and wire product, 1940. 14: p. 655-676.

46. Sandelin, R.W., Galvanizing Characteristics of Different Types of Steels. Wire

and wire product, 1940. 14: p. 721-749.

47. Sandelin, R.W., Galvanizing Characteristics of Different Types of Steel. 1941:

American Hot Dip Galvanizers Association.

48. Sandelin, R., Modern Trends in Steel as Affecting Hot Dip Galvanizing.

American Hot Dip Galvanizers Association, Washington, DC, 1963.

49. Habraken, L. Influence of Additional Alloying Elements on Corrosion

Resistance of Hot Dip Galvanised Steels. in Proceedings of 12th

International Galvanizing Conferencep 1979. Paris: Zinc Development

Association.

50. Guttman, H. and P. Niessen, Reactivity of silicon steels hot-dip galvanizing.

Canadian Metallurgical Quarterly, 1972. 11(4): p. 609-615.

51. Mackowiak, J. and N. Short, Metallurgy of galvanized coatings. International

metals reviews, 1979. 24(1): p. 1-19.

52. Horstmann, D. and F. Peters, The reaction between iron and zinc. London:

Zinc Development Association, 1978.

53. Kozdras, M. and P. Niessen, Silicon-induced destabilization of galvanized

coatings in the sandelin peak region. Metallography, 1989. 22(3): p. 253-267.

54. Reumont, G., P. Perrot, and J. Foct. Validation of the Modelling of a Solid-

Liquid Reaction by A Solid-Vapor Reaction. in MRS Proceedings. 1994:

Cambridge Univ Press.

204

55. Belfrage, S. and P. Ostrom. Hot Dip Galvanising in a Zinc Melt Containing

0.15% Nickel. in Proceedings of the 15th International Conference on Hot

Dip Galvanising. 1988.

56. Sokolowski, R. Edmund Husserl and the Phenomenological Tradition Essays

in Phenomenology. in Proceedings of 15th International Galvanizing

Conference. 1988. Rome: ZDA, GE4.

57. Krepski, R.P. Nickel-Based Pretreatment to Solve the Silicon Steel. in

Proceedings of 15th International Galvanizing Conference (1988). 1988.

Rome: Zinc Development Association, London.

58. Reumont, G., P. Perrot, and J. Foct, Thermodynamic study of the galvanizing

process in a Zn–0.1% Ni bath. Journal of Materials Science, 1998. 33(19): p.

4759-4768.

59. Chen, Z., et al., Technigalva and other developments in batch hot-dip

galvanizing. JoM, 1992. 44(1): p. 22-26.

60. Porter, F.C., Zinc handbook: properties, processing, and use in design. 1991:

CRC Press.

61. Sebisty, J. and R. Palmer, Hot dip galvanizing with less common bath

additions. Hot Dip Galvanizing. Pergamon Press, New York, 1967, p. 235-

265, 1967.

62. Reumont, G., J. Foct, and P. Perrot. New possibilities for the galvanizing

process: The addition of manganese and titanium to the zinc bath. in

Nineteenth International Galvanizing Conference,, Intergalva. 2000.

63. Adams, G. and J. Zervoudis, A new alloy for galvanizing reactive steel.

Proceedings Intergalva, 1997.

64. Chaplin, C., A. Potts, and A. Curtis. Degradation of wire rope mooring lines

in SE Asian waters. in Offshore Asia Conference. 2008. Kuala Lumpur.

65. API, R.P.S., Design and Analysis of Station Keeping Systems for Floating

Structures. 2005, American Petroleum Institute.

66. DNV-OS-E301, Position Mooring, in Standard Offshore. 2004: Det Norske

Veritas.

67. Suzumura, K. and S.-i. Nakamura, Environmental factors affecting corrosion

of galvanized steel wires. Journal of materials in civil engineering, 2004.

16(1): p. 1-7.

205

68. Ropes, B., ed. Ropes for deep water moorings. 1979, British Ropes

Publication 1156.

69. Chaplin, C.R. and A.E. Potts, Wire Rope Offshore-A Critical Review of Wire

Rope Endurance Research Affecting Offshore Applications. 1991.

70. Swan, J. The Corrosion Resistance of Wire Products in Marine Applications.

in Offshore Technology Conference. 1970: Offshore Technology Conference.

71. Husain, Z. and R. Cottis, The Influence of Seawater Corrosion on the Fatigue

Strength of Steel Wire Rope. Fatigue of Engineering Materials and Structures.,

1986. 2: p. 387-392.

72. Thorpe, T., A. Rance, and D. Silvester, The fatigue of electrogalvanised wire

used in the manufacture of wire ropes. Report by the Materials Development

Division. Atomic Energy Research Establishment (AERE), Harwell, UK,

1985.

73. Thorpe, T. and A. Rance. The Tensile Fatigue of Wire Rope: A New Approach.

in Offshore Technology Conference. 1983: Offshore Technology Conference.

74. Pearson, B. and R. Waterhouse. The fretting corrosion in sea water of

materials used in off-shore structures. in International Congress on Metallic

Corrosion. 1984.

75. Pearson, B. and R. Waterhouse, The fretting of steels in seawater. Tribology

Offshore, 1984: p. 49-60.

76. Waterhouse, R., B. Pearson, and R. Smallwood. The effectiveness of zinc

galvanised coatings in reducing fretting corrosion damage in steel ropes. in

Proc. 01PEEC Round Table Conf. 1985: National Engineering Laboratory

Glasgow.

77. Waterhouse, R. and D. Taylor, Fretting fatigue in steel ropes. Lubric. Eng.,

1971. 27(4): p. 123-127.

78. Prosek, T., et al., Corrosion mechanism of model zinc–magnesium alloys in

atmospheric conditions. Corrosion Science, 2008. 50(8): p. 2216-2231.

79. Volovitch, P., et al., Understanding corrosion via corrosion product

characterization: II. Role of alloying elements in improving the corrosion

resistance of Zn–Al–Mg coatings on steel. Corrosion Science, 2011. 53(8): p.

2437-2445.

80. Ogle, K., et al., Localized electrochemical methods applied to cut edge

206

corrosion. Journal of the Electrochemical Society, 2000. 147(10): p. 3654-

3660.

81 Pelerin, S., Corrosion mechanism and reinforced protection of hot-dipped

coated steel wire in seawater, in Mechanical Engineering. 1982, Northeastern

University: London.

82. Allegra, L. and J.C. Zoccola, Intergranular zinc embrittlement and its

inhibition by phosphorus in 55 pct Al-Zn-coated sheet steel. Mater. Perform.,

1983. 5(22).

83. Townsend, H. and J. Zoccola, Atmospheric corrosion resistance of 55% Al–

Zn coated sheet steel: 13-year test results. Materials Performance, 1979.

18(10): p. 13-20.

84. Tsuru, T., K.-I. Tamiya, and A. Nishikata, Formation and growth of micro-

droplets during the initial stage of atmospheric corrosion. Electrochimica

acta, 2004. 49(17): p. 2709-2715.

85. Tsujimura, T., A. Komatsu, and A. Andoh. Influence of Mg content in coating

layer and coating structure on corrosion resistance of hot-dip Zn–Al–Mg

alloy coated steel sheet. in Proceedings of the Galvatech. 2001.

86. Kawafuku, J., et al., Properties of zinc alloy coated steel sheets obtained by

continuous vapor deposition pilot-line. 1991, SAE Technical Paper.

87. Morishita, M., et al., Improvement in the Electrodeposition of Corrosion

Resistance of Zinc-plated Magnesium from a Molten Salt. ISIJ international,

1996. 36(6): p. 714-719.

88. Morishita, M., K. Koyama, and Y. Mori, Inhibition of anodic dissolution of

zinc-plated steel by electrodeposition of magnesium from a molten salt. ISIJ

international, 1997. 37(1): p. 55-58.

89. Morishita, M., K. Koyama, and Y. Mori, Self-healing ability of zinc-plated

steel coated with magnesium electrodeposited from a molten salt. Materials

Transactions, JIM, 1997. 38(8): p. 719-723.

90. Hausbrand, R., M. Stratmann, and M. Rohwerder, Delamination resistant

zinc alloys: Simple concept and results on the system zinc-magnesium. Steel

research international, 2003. 74(7): p. 453-458.

91. Vlot, M., et al. MagiZincTM: a new generation of hot-dip galvanised

products. in Proceedings of the Galvanized Steel Sheet Forum, ILZRO and

207

IZA, Duesseldorf, Germany. 2006.

92. Koll, T., et al., Properties and potential applications of novel ZnMg alloy

coatings on steel sheet. Revue de Métallurgie, 2004. 101(7-8): p. 543-550.

93. Townsend, H., Technical Note: On the Effects of Magnesium on the

Atmospheric Corrosion Resistance of Galvanized Sheet Steel. Corrosion,

1988. 44(4): p. 229-230.

94. Dagbert, C., et al., Effect of Additive Elements in Galvanizing Baths on

Atmospheric Corrosion Resistance of Galvanized Steels. Materiaux et

Techniques(Paris), 1990. 78(7): p. 11-16.

95 Zhang, X., Corrosion and Electrochemistry of Zinc. New York, Plenum Press.,

1996.

96. Kurosaki, M., et al., Zn-Al-Mg-Si-alloy plated steel product having excellent

corrosion resistance and method for preparing the same. 2003, Google

Patents.

97. Oh, M.S., et al., Molten zinc alloy plated steel strip having excellent

corrosion resistance and external surface and method for manufacturing

same. 2014, Google Patents.

98. Honda, K., W. Yamada, and K. Ushioda, Solidification structure of the

coating layer on hot-dip Zn-11% Al-3% Mg-0.2% Si-coated steel sheet.

Materials transactions, 2008. 49(6): p. 1395-1400.

99. Li, S., et al., Study on the Corrosion Mechanism of Zn-5Al-0.5 Mg-0.08 Si

Coating. Journal of Metallurgy, 2011. 2011.

100. Xu, H., Study on the Process and Anticorrosion Mechanism of Hot Dipping

Zn-Al-Mg Alloy Coating. 2009, ShanDong University, China: Jinan.

101. Schuerz, S., et al., Corrosion behaviour of Zn–Al–Mg coated steel sheet in

sodium chloride-containing environment. Corrosion Science, 2009. 51(10): p.

2355-2363.

102. Dutta, M., A.K. Halder, and S.B. Singh, Morphology and properties of hot

dip Zn–Mg and Zn–Mg–Al alloy coatings on steel sheet. Surface and

Coatings Technology, 2010. 205(7): p. 2578-2584.

103. Dutta, M. and S.B. Singh, Effect of strip temperature on the formation of an

Fe 2 Al 5 inhibition layer during hot-dip galvanizing. Scripta materialia, 2009.

60(8): p. 643-646.

208

104. Fontana, M.G., Corrosion engineering. 2005: Tata McGraw-Hill Education.

105. Prosek, T., et al., Corrosion properties of model Zinc-Magnesium alloys.7th

International Conference Zinc and Zinc alloy coated steel sheet, Galvatech

2007 Osaka Japan. p. 54-63.

106. Hausbrand, R., M. Stratmann, and M. Rohwerder, Corrosion of zinc–

magnesium coatings: Mechanism of paint delamination. Corrosion Science,

2009. 51(9): p. 2107-2114.

107. Tanaka, S., et al. The performance of Zn–Al–Mg–Si hot-dip galvanized steel

sheet. in Proceedings of the Galvatech. 2001.

108. Persson, D., et al., In situ infrared reflection spectroscopy studies of the initial

atmospheric corrosion of Zn–Al–Mg coated steel. Corrosion Science, 2013.

72: p. 54-63.

109. Schuerz, S., et al., Corrosion behaviour of Zn–Al–Mg coated steel sheet in

sodium chloride-containing environment. Corrosion Science, 2009. 51(10): p.

2355-2363.

110. Schürz, S., et al., Chemistry of corrosion products on Zn–Al–Mg alloy coated

steel. Corrosion Science, 2010. 52(10): p. 3271-3279.

111. Prosek, T., et al., Composition of corrosion products formed on Zn–Mg, Zn–

Al and Zn–Al–Mg coatings in model atmospheric conditions. Corrosion

Science, 2014. 86: p. 231-238.

112. Maalman, T.F.J., R. Bleeker, and M.J. Vlot, Steel sheet with hot dip

galvanized zinc alloy coating and process to produce it. 2014, Google Patents.

113. Feng, L., L. Shun, and Y. Honggang, Low-aluminum low-magnesium zinc-

aluminum-magnesium plated steel plate and method for producing same.

2013, Google Patents.

114. Yeung, Y.C.T. and Walton, J.M, Accelerated block tension fatigue testing wire

rope for offshore use. OIPEEC, 1985. NEL Glasgow.

115. Venkatesan, P. , Anand B. and Matheswaran, P., Influence of formazan

derivatives on corrosion inhibition of mild steel in hydrochloric acid medium,

Journal of chemistry, 2009. Vol. 6, No. S1, : p. 438-444.

116. Burstein, G.T., A century of Tafel's equation: A commemorative issue of

corrosion science, 2005. Vol. 47, Issue 12, : p. 2858-2870.

117. Nam, W.J., et al., Effect of interlamellar spacing on cementite dissolution

209

during wire drawing of pearlitic steel wires. Scripta materialia, 2000. 42(5): p.

457-463.

118. Song, H.R., E.G. Kang, and W.J. Nam, Effect of alloying elements on work

hardening behavior in cold drawn hyper-eutectoid steel wires. Materials

Science and Engineering: A, 2007. 449: p. 1147-1150.

119. Tarui, T., et al., Metallurgical design of ultra high strength steel wires for

bridge cable and tire cord. Metallurgy, Processing and Applications of Metal

Wires, 1996: p. 87-96.

120. Boyer, H.E., Metals handbook: Failure analysis and prevention. 1975:

American Society for Metals.

121. Eric M. Taleff, Pearlite in ultrahigh carbon steels: Heat treatments and

mechanical properties. Metallugical and material tractions A, 1996, Vol. 27,

Issue 1 : p. 111-118.

122. Shen, Y., et al., Fretting wear behaviors of steel wires under friction-

increasing grease conditions. Tribology International, 2011. 44(11): p. 1511-

1517.

123. Zhang, D., et al., Fretting wear behaviors of steel wires in coalmine under

different corrosive mediums. Wear, 2011. 271: p. 866-874.

124. Ge, S., R. Qu, and W. Xie, Reliability techniques for winders in mine. China

University of Mining and Technology, 1994.

125. McAdam Jr, D. Some Factors Involved in Corrosion and Corrosion-Fatigue

of Metals. in Proceedings. 1928.

126. Miller, K.J. and Akid, R., The Application of Microstructural Fracture

Mechanics to Various Metal Surface States.Proceedings Royal Society

London A, 1996. 452: p. 1411-1432.

127. Reumont, G., et al., The effects of an Fe–Zn intermetallic-containing coating

on the stress corrosion cracking behavior of a hot-dip galvanized

steel.Surface and Coatings Technology, 2001. 139(2–3): p. 265-271.

128. Foct, J., Relaxation of stresses by cracks in intermetallic coatings:

application to galvanizing. Scripta metallurgica et materialia, 1993. 28(1): p.

127-132.

129. Cardou, A. and C. Jolicoeur, Mechanical models of helical strands. Applied

Mechanics Reviews, 1997. 50: p. 1-14.

210

130. Wang, D., et al., Finite element analysis of hoisting rope and fretting wear

evolution and fatigue life estimation of steel wires. Engineering failure

analysis, 2013. 27: p. 173-193.

131. Jones, D.A., Principles and prevention of corrosion. 1992: Macmillan.

132. Odnevall, I. and C. Leygraf, Formation of NaZn 4 Cl (OH) 6 SO 4· 6H 2 O in

a marine atmosphere. Corrosion Science, 1993. 34(8): p. 1213-1229.

133. Ligier, V., et al., Formation of the main atmospheric zinc end products: NaZn

4 Cl (OH) 6 SO 4· 6H 2 O, Zn 4 SO 4 (OH) 6· nH 2 O and Zn 4 Cl 2 (OH) 4

SO 4· 5H 2 O in [Cl−][SO 4 2−][HCO 3−][H 2 O 2] electrolytes. Corrosion

Science, 1999. 41(6): p. 1139-1164.

134. Fujita, S. and H. Kajiyama, Quantitative analyses of crystalline compositions

of iron rust on automobiles under service conditions. ISIJ international, 2001.

41(3): p. 275-280.

135. Yadav, A., et al., Effect of Fe–Zn alloy layer on the corrosion resistance of

galvanized steel in chloride containing environments. Corrosion Science,

2007. 49(9): p. 3716-3731.

136. Mouanga, M., et al., Galvanic corrosion between zinc and carbon steel

investigated by local electrochemical impedance spectroscopy.

Electrochimica acta, 2013. 88: p. 6-14.

137. Morimoto, Y., et al., Excellent Corrosion-resistant Zn-Al-Mg-Si Alloy Hot-dip

Galvanized Steel Sheet" SUPER DYMA". Shinnittetsu Giho, 2002: p. 22-24.

138. Nishimura, K., K. Kato, and H. Shindo, Highly corrosion-resistant Zn-Mg

Alloy galvanized steel sheet for building construction materials. Nippon Steel

Technical Report, 2000. 81(0).

139. Shindo, H., et al., Developments and properties of Zn-Mg galvanized steel

sheet dymazinc have excellent corrosion resistance. Nippon steel technical

report. Overseas, 1999(79): p. 63-67.

140. Nishimura, K., et al. Microstructure and corrosion behaviour of Zn–Mg–Al

hot-dip galvanized steel sheet. in Proceedings of the Galvatech. 1998.

141. Shindo, H., K. Nishimura, and K. Kato. Anticorrosion in atmospheric

exposure of Zn–Mg–Al hot dip galvanized steel sheet. in Proceedings of the

Galvatech. 1998: p. 433-436.

142. Tsujimura, T., A. Komatsu, and A. Andoh. Influence of Mg content in coating

211

layer and coating structure on corrosion resistance of hot-dip Zn–Al–Mg

alloy coated steel sheet. in Proceedings of the Galvatech '01, International

Conference on Zinc and Zinc Alloy Coated Steel. 2001. Brussels, Belgium.

143. Komatsu, A., et al., Hot-dip Zn-Al-Mg coated steel sheet excellent in

corrosion resistance and surface appearance and process for the production

thereof. 1998, Google Patents.

144. Yao, C., et al., Effects of Mg content on microstructure and electrochemical

properties of Zn–Al–Mg alloys. Journal of Alloys and Compounds, 2015. 645:

p. 131-136.

145. De la Fuente, D., J. Castano, and M. Morcillo, Long-term atmospheric

corrosion of zinc. Corrosion Science, 2007. 49(3): p. 1420-1436.

146. Odnevall, I.and Leygraf, C., The formation of Zn4Cl2(OH)4SO4 . 5H2O in an

urban and an industrial atmosphere. Corrosion Science, 1994. 36(9): p.

1551-1559.

147. Hosking, N.C., et al., Corrosion resistance of zinc-magnesium coated steel.

Corrosion Science, 2007. 49(9): p. 3669-3695.

148. Volovitch, P., et al., Understanding corrosion via corrosion product

characterization: I. Case study of the role of Mg alloying in Zn-Mg coating

on steel. Corrosion Science, 2009. 51(6): p. 1251-1262.

149. Jönsson, M., D. Persson, and D. Thierry, Corrosion product formation during

NaCl induced atmospheric corrosion of magnesium alloy AZ91D. Corrosion

Science, 2007. 49(3): p. 1540-1558.

150. Thierry, D., et al., Corrosion protection and corrosion mechanisms of

continuous galvanized steel sheet with focus on new coating alloys. Galvatech

‘11, Genova, Italy [6]“ZM EcoProtect®-The innovative Coating”, brochure

of ThyssenKrupp Steel Europe AG, 2010.

151. Hausbrand, R., M. Stratmann, and M. Rohwerder, The physical meaning of

electrode potentials at metal surfaces and polymer/metal interfaces:

consequences for delamination. Journal of the Electrochemical Society, 2008.

155(7): p. C369-C379.

152. Diler, E., et al., Stability of ZnMgO oxide in a weak alkaline solution. Thin

Solid Films, 2012. 520(7): p. 2819-2823.

212

LIST OF PUBLICATIONS

1. M.H.Cho, S.Salleh, N.Ahmad, A.Ourdjini, E.Hamzah,Influence of Carbon

Content On The Mechanical Properties of Ultra-high Strength Of Coated

Steel Wire for Oil and Gas Industries. 2012: Journal Technology University

Technology Malaysia.

2. M.H.Cho, F.Mohamed, A.Ourdjini, E.Hamzah, Factors Affecting Fatigue

Behaviour Properties of Ultra-High Strength Steel Rope for Offshore Oil and

Gas Industry. Composite Materials for Offshore Operations, 2011. Offshore

Asia ConferenceKuala Lumpur.

3. M.H.Cho, Zinc alloy plated wire having excellent corrosion resistance,

filing no.: PCT /KR2025/011826, 제 15-153249호.

influence of steel composition on the mechanical...

Documents