the corrosion in the railway wagon revision

8/3/2019 The Corrosion in the Railway Wagon Revision

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2011

Nurhasanudin

Metallurgical Departement

11/25/2011

The Corrosion In The Railway Wagon


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Contents

Page

Preface .......................................................................................................... 3

Corrosion That May Occur In Railway Wagon ........................................ 4

Causes Of Corrosion In Railway Wagon ................................................... 7

Areas Subject To High Rate Of Corrosion In Passenger Wagon .......... 10

Prevention ................................................................................................... 11

Conclusion .................................................................................................. 13

References ................................................................................................... 14


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Preface

Railway is a public transportation which is always be a choice for the most

people to do travel to cross many place. The railway work out in many

environment and cilmate which vary like marine atmospheric, industrial

atmospheric, and even as dry season, and rainy season the railway still operated

Due to the impact such as environment and climate, the body of railway

wagon can be corroded easily, which will affect the transportation safety and

maintenance of wagon body.

Picture 1. The railway with corrosion problem

This railway unit was in very poor condition with a big corrosion problem.

Thats way we need to investigated more about corrosion problem in railway

especially the wagon body.


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The Corrosion That May Occur in Railway Wagon

The pictures below are examplize the corrosion in the wagon body that may occur

(a)

(b) (c)

Picture 2. Corrosion in the window hopper

Source : The International Railway Preservation Society

Picture 2 showing the corroded window hopper. The hooper frame made

from brass strip act as holder and joined to the along side of alumunium plat to

holding the alumunium in place, and form. Picture 2. (a) is the hopper before

installation, picture 2 (b) and (c) showing the hopper after usage.

After usage, the along side of alumunium has completely powdered

through. The picture 2 (c) showing where the alumunium has powdered. This is

probably caused by the close proximity of different metals and the presence of

water. Aluminium is the less noble of this combination of metals and electrolysis

has eaten away the aluminium. This corrosion is known as galvanic corrosion.


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(a) (b)

Picture 3. the corrosion in the : (a), (b) vestibule ; (c) end vestibule ; (d) roof

Picture 3 showing the area that corroded in more specific area in wagon.

The uniform corrosion is occur in almost all of the surface area in the vestibule,

end vestibule and the roof. The corrosiove environment must have the same

access to all part of the metal surface and the metal it self must be matallurgicallyand compositionally uniform [Deny A. Jones, 1992]

. The picture 3 (a) showing the most serieous damage caused by uniform

corrosion. The arrow in picture 3 (b) showing the area with crevice corrosion.

Corrosion within a crevice maybe coused in atmospheric exposures by retention

of water, while the outer surface can drain and dry.

Corrosion of an alloy is often greater in the small sheltered volume of the

crevice created by contact with another material. The second material maybe part

of a fastener (bolt, rivet, washer) of the same or different alloy.

(c) (d)

crevice

Galvanic

corrosion


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If the crevice is made up of differing alloys or if the deposit is conductive

(magnetite or graphite) crevice corrosion may be compounded by galvanic

effects. [Deny A. Jones, 1992]

The arrow in picture 3(c) is pointing to the area with galvanic corrosion

problem which occur in coupled pillar beetwen two dissimilar metal alloys. When

two dissimilar alloys are coupled in the presence of a corrosive electrolyte one of

them is preferentially corroded, while the other one is protected from corrosion.

Based galvanic series, metal with more negative potential will corroded, and the

more positif one will be protected. [Deny A. Jones, 1992]

The railway wagon, in the selection material still use a different material

which are coupled togather because there is amount of advantages. In design ofwindow hopper, there was two kind of different metal are used, alumunium and

brass. Aluminum is lighter material, and have a good look, but it self have a

disadvantages, alumunium is less tough. In the other hand, brass have a good

toughness but more heavy. For that reason, those two material get combined.

Improved stiffness, Reduced density/weight, so the window hopper could be moer

lighter, but have a good toughness.


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Couses Corrosion In Railway Wagon

Coaches are susceptible to marine atmospheric corrosion and industrial

atmospheric corrosion

Table 1. Environmental pollutan causing corrosion

Source: Nace Corrosion Engineer's Reference Handbook.


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Atmospheric variable:

1. Climate conditionMetal surface located in areas where they become wet and retain moisturegenerally corroded more rapidly then surfaces exposes to rain. The rain has a

tendency to wash the surface and remove particles of dust that can lead to

differential aeration corrosion, exception would be areas that subject to acid rain.

2. Time of wetnessTime of wetness is a critical variable with respect to the extent of corrosion

experienced. The time of wetness determines the duration of the electrochemical

process. The thickness and the chemical composition of the water film are both

importantThe critical relative humidity is the humidity below which water will not

form on a clean metal surface and thus electrochemical or wet corrosion will not

occur. The actual relative humidity will change depending on the surface

condition of the metal [ASM Handbook, 9th

ed., volume 13: Corrosion, 1992]

Marine Atmospheric Corrosion:

Sea water and open seas has a hidh salt content of about 3,5%. The table

salt ( sodium chloride ) makes sea water a good conductor of electricity, as the

presence of an electrolyte is necessary for corrosion, it leads to corrosion.

In the marine atmospheric corrosion, chloride ions play a major role ininducing corrosion. Approaching the sea coast, air is laden with increasing

amounts of sea salt, in particular NaCl. Sulfates exert a lesser influance,

bicarbonates hinder corrosion

Industrial atmospheric corrosion

At industrial area, appreciable amounts of SO2, this converts to sulfuric

acid, and lesser amounts of H2S, NH3, NO2 and various suspended salts are

encountered. This is the main reason for coaches getting easily corroded near

industrial areas. Most corrosion can take place when oxygen is present and

therefore level of dissolved oxygen is important, in the open sea there is about 4

8 parts per million, ample to allow steel to corrode. Gases like SO2, which

originate from burning of coal, gas and gasoline, would also cause corrosion.

Causes of corrosion in ailway coaches ( wagon) are :

1. Water seepage through the flooring to the top of trough floor.2. Leakage of water through lavatory flooring3. Missing of corrode chute and drain pipe.4. Defective water pipe fittings.


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5. Absence of surface preparation during replacement of commode and drainpipes

6. Habits of flushing the flooring with the water jet for cleaning7. The condition of air trapped in between trough floor and flooring due to

climate changes

8. Striking of flying ballast when the train is running.9. Design of window seal leaves the gap between the side panel to allow the rain

water flow through the panel and to drain out at the bottom.

10.Blockage of drain water by accumulated dust on top of trough floor11.Dissimilar metals joint12.Design allow space


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Areas Subject To High Rate Of Corrosion In Passenger

Wagon

Areas subject to high rate of corrosion in passenger wagon are :

1. Trough floor: areas adjacent to lavatory, doorways, luggage compartmentin SLR (sleeper) and kitchen area of pantry car.

2. Side wall bottom: area below lavatory and between body side pillars3. Body pillars: bottom portion of pillar near doorways and lavatory area4. Cross bearers: joint between sole bar and cross bearers.5. Body side door: bottom of door due to accumulation of dust6. Battery boxes: corrosion due to acid action7. Roof: ventilator and area around it.8. Joint between frame ( carbon steel ) and roor (stainless steel)


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Prevention

In order to overcome corrosion, the following steps are carried out:

1. Use of HSLA : CORTEN Steel2. Use of corrosion resistant material like stainless steel3. Surface preparation and painting (organic coating)4. Use simillar metals which are welded or joined togather

Corten Steel :

Corten steel (often referred to as Cor

Ten) is a weather resistant steelwhich could more accurately be termed as an "Atmospheric Corrosion Resistant

Steel" It is a copper chromium alloy steel this alloy displays a greater level of

resistance to atmospheric weathering when compared to other unalloyed steels.

It's chemical composition promotes the early formation of an adhering protective

layer of rust when exposed to the elements.

Weathering steel, best-known under the trademark CORTEN A steel and

sometimes written without the hyphen as "CORTEN A steel", is a group of steel

alloys which were developed to obviate the need for painting, and form a stable

rust-like appearance if exposed to the weather for several years.

United States Steel Corporation (USS) holds the registered trademark on

the name CORTEN A. The original CORTEN A received the standard

designation ASTM A 242 TYPE-1("COR-TEN A") from the ASTM International

standards group. Newer ASTM grades are A 588 ("CORTEN A") and A 606 for

thin sheet. All alloys are in common production and use. JIS G 3125:2004

Japanese grade for weather resistant steel plates. Superior atmospheric corrosion

resisting rolled steels This Standard specifies the rolled steel having high

atmospheric corrosion resistance, to be used for vehicle, building, steel tower and

other structure. IRSM 41-97 Corrosion Resistance SteelIndian grade for weather

resistant steel plates. IRSM 41-97 standard of Indian railways specifically formedfor wagon body due to it high resistance to corrosion, Major wagon builder being

Rail Coach Factory. CORTEN A, ASTM 588 GR.A, ASTM 242 TYPE-1, JISG

3125 SPA-H, IRSM 41-97 Weather & Corrosion Resistant Steel Chemical

Properties.

Table 2. Chemical Composition of Corten Steel (source:www.ajmarshall.com)
http://www.ajmarshall.com/http://www.ajmarshall.com/http://www.ajmarshall.com/http://www.ajmarshall.com/


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Table 3. Mechanical Properties Corten A (source:www.ajmarshall.com)

Table 4. Mechanical Properties Corten B (source:www.ajmarshall.com)

Use Of Stainless Steel And Hsla And Mild Steel Which Are All Welded Together

When under going dissimilar welding, defects are caused because of

change in metal composition. Under such conditions, corrosion in dissimilar parts

can be minimized if the weld metal has better corrosion resistance, strength and

mechanical properties compared to the parent metal. For e.g. when welding

stainless steel to mild steel, the composition of weld metal should be closer to that

of stainless steel composition. The usage of copper coated plain carbon steel wireas electrode under CO2 as shielding media is the usual practice that deviates from

the composition of the parent metal. Under such circumstance the weld metal is

more easily prone to corrosion compared to the parent metal.
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Conclusion

The sorrosion may occur in the corrosive atmospheric

Corrosion can be mitigated by :

a) Avoiding usage of dissimilar metalsb) Use simple designc) Good coating and the preparation or cleaningd) Choose a material with a good resistant to the corrosion

Joining two material that have a very diferent character is able to do, to get a

different charcteristic.


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References

ASM Handbook, 9th

ed., volume 13: Corrosion, 1992

Denny A. Jones, Principles and Prevention of Corrosion, Macmillan Publishing

Co, New York, 1992

Sivakumar, Durgacharan. CORROSION PREVENTION IN RAILWAY COACHES,

TRI-Service Corrosion Conference, 2007

Triyono; Diharjo K.; Ilman Nur & Soekrisno. Fakultas Teknik UNS, Penelitian,

Dikti, RUT, 2005.www.ajmarshall.com

www.irps-wl.org.uk/3916.shtml

www.mastell.co.uk/corten-weather-resistant-steel.htm
http://www.ajmarshall.com/http://www.ajmarshall.com/http://www.irps-wl.org.uk/3916.shtmlhttp://www.irps-wl.org.uk/3916.shtmlhttp://www.mastell.co.uk/corten-weather-resistant-steel.htmhttp://www.mastell.co.uk/corten-weather-resistant-steel.htmhttp://www.mastell.co.uk/corten-weather-resistant-steel.htmhttp://www.irps-wl.org.uk/3916.shtmlhttp://www.ajmarshall.com/

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