3rd review batch 7

8/8/2019 3rd Review Batch 7

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ANALYSIS OF WELDING PARAMETERS FOR

FERRITE NUMBER IN TIG WELDED

202 GRADE STAINLESS STEEL PLATES

PRESENTED BY

N.L.KAARTHIKRAM (06BME21)S.KALAIRAJ (06BME22)

E.PRAVEEN (06BME33)

GUIDED BY

Mr.R.SUDHAKARAN,

(SENIOR LECTURER)

DEPARTMENT OF MECHANICAL ENGINEERING


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Determination of ferrite number of SS202 grade steels.

Optimization of process parameters

Gun angle.

Welding current.

Gas flow rate.

Plate length.

Welding speed, on ferrite number.


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Effect of Composition on Corrosion Resistance of High-Alloy Austenitic Stainless Steel Weld Metals was publishedby P.I. Marshall and T.G. Gooch in December 1992 whichstated the composition of stainless steel alloys for

corrosion resistance in them.

M. Vasudevan and A.K. Bhaduri in 2004 published theirwork on Prediction of Ferrite Number in Stainless SteelWelds in which a model was developed for accurate

composition only dependent FN prediction methodcurrently reported in literature.


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Identification of limits of process variables,

Developing the design matrix,

Conducting experiments as per the design matrix,

Determination of ferrite number of stainless steel grade-

202,

Optimization of process parameters using non traditional

optimization technique.


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The standard value assigned to austenitic stainless steel todenote a specific ferrite content.

Excessive ferrite in stainless steel can result in poor ductility,toughness, and corrosion resistance.

Insufficient ferrite can also produce inferior mechanical andcorrosion resistance properties.

Hence, control of ferrite in stainless steel cladding is essential toobtain the required mechanical and corrosion-resistantproperties.

Hence, control of ferrite in stainless steel is essential to obtainrequired corrosion-resistant properties ,for which we optimizethe parameters in welding to weld a stainless steel grade 202plate with optimum ferrite number.


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It is a type of fusion welding.

In this welding, an electric arc is produced between a non-consumable tungsten electrode and the work piece.

When the arc is produced, the inert gas from the cylinderpasses through the welding head around the electrode,which surrounds the arc and protects the weld from

atmospheric effects.


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EXPERIMENTAL PROCEDURESEXPERIMENTAL PROCEDURES

The experiments wereconducted using LincolnV 350 Pro Electric DigitalWelding Machine.

A servo motor driven

manipulator was used tomaintain uniformwelding speed.


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EXPERIMENTAL PROCEDURESEXPERIMENTAL PROCEDURES

The welding gun is held stationary inThe welding gun is held stationary ina frame above the table and it isa frame above the table and it isprovided with an attachment forprovided with an attachment forsetting the required welding gunsetting the required welding gun

angle.angle.

Argon is used as the shielding gasArgon is used as the shielding gasand its flow rate is varied for eachand its flow rate is varied for eachexperiment as per the requirements.experiment as per the requirements.


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PLAN OF WORKPLAN OF WORK

Identifying the process variablesIdentifying the process variables

Developing the design matrixDeveloping the design matrix

Conducting the experiments as per the design matrixConducting the experiments as per the design matrix

Development of mathematical modelsDevelopment of mathematical models

Evaluation of coefficients of the modelsEvaluation of coefficients of the models

Checking adequacy of the modelsChecking adequacy of the models

Testing the regression coefficients of the modelsTesting the regression coefficients of the models

Validation of the mathematical modelsValidation of the mathematical models

Analyzing theAnalyzing the

resultsresults


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LIMITS OF PROCESS VARIABLESLIMITS OF PROCESS VARIABLES

The design plan wasdecided based on thepractical considerationsfor the system

Factor Upperlimit

Lowerlimit

Weldingcurrent (I) amps

110 70

Weldingspeed (V)mm/min

120 80

Gas flow rate(Q) liter/min

25 5

GunAngle ()Degrees

90 50

Plate Length (L)mm

200 100


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LIMITS OF PROCESS VARIABLESLIMITS OF PROCESS VARIABLES

Process

parameters

Limits

-2 -1 0 +1 +2

Weldingcurrent amps

70 80 90 100 110

WeldingSpeedmm/min

80 90 100 110 120

Gas flow rate

Liter/min

5 10 15 20 25

Gun angleDegrees

50 60 70 80 90

Plate Lengthmm

100 125 150 175 200


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DETERMINATION OF FERRITE NUMBERDETERMINATION OF FERRITE NUMBER

The ferrite number was measured using the Feritscope.The ferrite number was measured using the Feritscope.


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DESIGN MATRIXDESIGN MATRIX

The design matrix chosen

to conduct the experimentswas five factor, five levelscentral composite rotatabledesigns consisting of 32 setsof coded conditions .

This design matrixcomprises a full replicationfactorial design i.e. 24 = 16factorial design plus 7 centerpoints and 8 star points.


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MATHEMATICAL MODELMATHEMATICAL MODEL

0.669-0.006*2-0.086*V2-0.037*L2+0.094*I2-0.052*V2*V2 -

0.029*L2*L2+0.006*Q2*Q2+0.073*2*V2-0.07*2*L2-

0.004*2*I2+0.05*V2*L2-0.042*V2*I2+0.012*I2*Q2

Fn=Fn=

The mathematical model was developed using quality america pc IV DOE softwareThe mathematical model was developed using quality america pc IV DOE software

GUN ANGLE ()

WELDING SPEED (V)

PLATE LENGTH (L)

WELDING CURRENT (I)

GAS FLOW RATE (Q)

where,where,


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R-ratio = M.S-FACTORS / M.S PURE ERRORR-ratio = M.S-FACTORS / M.S PURE ERROR

= 1022.918= 1022.918

F-ratio = M.S-LACK OF FIT / M.S PURE ERRORF-ratio = M.S-LACK OF FIT / M.S PURE ERROR

= 2.355= 2.355

LACK OF FIT D.F = 12LACK OF FIT D.F = 12

PURE ERROR D.F = 7PURE ERROR D.F = 7

F-ratio (12,7)= 3.57F-ratio (12,7)= 3.57

LACK OF FIT D.F = 13LACK OF FIT D.F = 13

PURE ERROR D.F = 7PURE ERROR D.F = 7

F-ratio (13,7)= 3.55F-ratio (13,7)= 3.55

F-ratio (12,7) < STD . TAB .VALUEF-ratio (12,7) < STD . TAB .VALUE

2.355 < 3.572.355 < 3.57

R-ratio (13,7) > STD . TAB .VALUER-ratio (13,7) > STD . TAB .VALUE

1022.910 > 3.551022.910 > 3.55

HENCE THE MODEL IS ADEQUATEHENCE THE MODEL IS ADEQUATE

MODEL CALCULATIONMODEL CALCULATION


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Observed

predicted

error

0.62 0.62 -0.64516

0.64 0.64 0.3125

0.31 0.31 -1.29032

0.57 0.57 -0.35088

0.6 0.61 -2.33333

0.31 0.30 3.225806

0.45 0.46 -1.33333

0.48 0.48 -0.41667

0.9 0.90 -0.44444

0.9 0.90 -0.22222

0.42 0.43 -1.42857

0.68 0.67 1.764706

0.89 0.89 -0.44944

0.56 0.56 -0.71429

0.56 0.57 -1.42857

Observed

predicted

error

0.58 0.58 0.344828

0.7 0.68 2.714286

0.64 0.66 -2.65625

0.64 0.63 1.09375

0.29 0.29 0.344828

0.63 0.63 0.47619

0.49 0.48 2.244898

0.49 0.48 1.836735

0.85 0.86 -0.82353

0.7 0.69 1

0.7 0.69 1

0.68 0.67 1.617647

0.68 0.67 1.617647

0.67 0.67 0.149254

0.66 0.67 -1.36364

0.67 0.67 0.149254

0.66 0.67 -1.36364

ERROR CALCULATIONERROR CALCULATION

SINCE R2 VALUE IS NEAR BY 1 THEOBSERVED VALUE AND THE

PREDICTE DVALUE HAVE CLOSE

RELATION AND ARE MEANT TO BE

EQUAL.


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RESULTS AND DICUSSIONSRESULTS AND DICUSSIONS

Response Surface Regression: C6 versus C1, C2, C3, C4, C5

The analysis was done using coded units.

THE CONTOUR AND SURFACE GRAPHS FOR VARIOUS PARAMETERS WERE

DRAWN AND ANALYSED USING MINITAB 15 STATISTICAL SOFTWARE .

Contour Plot of C6 vs C2, C1










Surface Plot of C6 vs C2, C1











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2

0.000

0.25

0.50

0.75

-2

0 -2

2

C6, FN

C2, WELDING SPEED (V)

C1, GUN ANGLE ()

C3 0

C4 0

C5 0

Hold Values


C1, GUN ANGLE ()

C2,WELDINGSPEED(V

)

210-1-2

2

1

0

-1

-2

C3 0

C4 0

C5 0

Hold Values

>

< 0.2

0.2 0.4

0.4 0.6

0.6 0.8

0.8

C6


C1, GUN ANGLE ()

C2, WELDING SPEED

(V)

C3, PLATE LENGTH (L)

C4, WELDINGCURRENT (I)

C5, GAS FLOW RATE

(Q)

C6, FN


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2

0.20

0.4

0.6

0.8

-2

0 -22

C6, FN


C1, GUN ANGLE ()

C2 0

C4 0C5 0

Hold Values


C1, GUN ANGLE ()

C3,PLATELENGTH

(L)

210-1-2

2

1

0

-1

-2

C2 0

C4 0

C5 0

Hold Values

>

< 0.2

0.2 0.3

0.3 0.4

0.4 0.5

0.5 0.60.6 0.7

0.7 0.8

0.8

C6


C1, GUN ANGLE ()

C2, WELDING SPEED

(V)



C5, GAS FLOW RATE

(Q)

C6, FN


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2

0.5

0

0.7

-2

0.9

0 -2

2

C6, FN

C4, WELDING CURRENT (I )

C1, GUN ANGLE ()

C2 0

C3 0

C5 0

Hold Values


C1, GUN ANGLE ()

C4,

WELDINGCU

RRENT(I)

210-1-2

2

1

0

-1

-2

C2 0

C3 0

C5 0

Hold Values

>

< 0.5

0.5 0.6

0.6 0.7

0.7 0.8

0.8

C6


C1, GUN ANGLE ()

C2, WELDING SPEED

(V)



C5, GAS FLOW RATE

(Q)

C6, FN


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2

0.650 0

0.675

0.700

-2

0 -2

2

C6, FN

C5, GAS FLOW RATE ( Q)

C1, GUN ANGLE ()

C2 0

C3 0

C4 0

Hold Values


C1, GUN ANGLE ()

C5,

GASFLOWRA

TE(Q)

210-1-2

2

1

0

-1

-2

C2 0

C3 0

C4 0

Hold Values

>

< 0.66

0.66 0.67

0.67 0.68

0.68 0.69

0.69 0.70

0.70

C6


C1, GUN ANGLE ()

C2, WELDING SPEED

(V)

C3, PLATE LENGTH (L)C4, WELDING

CURRENT (I)

C5, GAS FLOW RATE

(Q)

C6, FN


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2

0.00 0

0.25

0.50

-2

0.75

0 -2

2

C6, FN



C1 0

C4 0

C5 0

Hold Values



C3,PLATELENG

TH(L)

210-1-2

2

1

0

-1

-2

C1 0

C4 0

C5 0

Hold Values

>

< 0.1

0.1 0.2

0.2 0.3

0.3 0.4

0.4 0.5

0.5 0.6

0.6 0.7

0.7

C6


C1, GUN ANGLE ()

C2, WELDING SPEED

(V)

C3, PLATE LENGTH (L)C4, WELDING

CURRENT (I)

C5, GAS FLOW RATE

(Q)

C6, FN


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20.4

0

0.6

0.8

-2

1.0

0 -2

2

C6, FN

C4, WELDING CURRENT (I )


C1 0

C3 0

C5 0

Hold Values



C4,WELDINGCURR

ENT(I)

210-1-2

2

1

0

-1

-2

C1 0

C3 0

C5 0

Hold Values

>

< 0.3

0.3 0.4

0.4 0.5

0.5 0.6

0.6 0.7

0.7 0.8

0.8 0.9

0.9

C6


C1, GUN ANGLE ()

C2, WELDING SPEED

(V)C3, PLATE LENGTH (L)

C4, WELDING

CURRENT (I)

C5, GAS FLOW RATE

(Q)

C6, FN


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2

0

0.4

0.6

-2

0.8

0 -2

2

C6, FN

C5, GAS FLOW RATE ( Q)


C1 0

C3 0

C4 0

Hold Values



C5,

GASFLOWRA

TE(Q)

210-1-2

2

1

0

-1

-2

C1 0

C3 0

C4 0

Hold Values

>

< 0.3

0.3 0.4

0.4 0.5

0.5 0.6

0.6 0.7

0.7

C6


C1, GUN ANGLE ()

C2, WELDING SPEED

(V)



C5, GAS FLOW RATE

(Q)

C6, FN


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20.4

0

0.6

-2

0.8

0 -2

2

C6, FN

C4, WELDI NG CURRENT (I )


C1 0

C2 0

C5 0

Hold Values



C4,

WELDING

CURRENT(I)

210-1-2

2

1

0

-1

-2

C1 0

C2 0

C5 0

Hold Values

>

< 0.3

0.3 0.4

0.4 0.5

0.5 0.6

0.6 0.7

0.7 0.8

0.8

C6


C1, GUN ANGLE ()

C2, WELDING SPEED

(V)



C5, GAS FLOW RATE

(Q)

C6, FN


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2

0.5

0

0.6

-2

0.7

0 -2

2

C6, FN

C5, GAS FLOW RATE (Q)


C1 0

C2 0

C4 0

Hold Values



C5,GASFLO

WRATE(Q)

210-1-2

2

1

0

-1

-2

C1 0

C2 0

C4 0

Hold Values

>

< 0.50

0.50 0.55

0.55 0.60

0.60 0.65

0.65 0.70

0.70

C6


C1, GUN ANGLE ()

C2, WELDING SPEED

(V)


C4, WELDING

CURRENT (I)

C5, GAS FLOW RATE

(Q)

C6, FN


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SCHEDULE OF WORKSSCHEDULE OF WORKS


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ACTIVITIES SCHEDULE

COLLECTION OF INFORMATION 07-09-2009 TO 28-09-2009

BUYING THE PLATES AND MATERIALSREQUIRED.

ON 16-12-2009

WELDING PROCESS. 28-12-2009 TO 04-01-2010

DETERMINATION OF FERRITENUMBER.

ON 18-01-2010

DEVELOPMENT THE DESIGN MATRIX. 20-01-2010 TO 27-01-2010

DEVELOPMENT OF MATHEMATICALMODEL (USING (DOE PC IV )).

ON 18-02-2010

ANALYSING THE RESULTS(USING (MINITAB)).

ON 02-03-2010

CONFIRMATORY TESTS 25-03-2010 TO 04-04-2010

PREPARATION OF REPORTS. BEFORE 7-04-2010

SCHEDULE OF WORKSSCHEDULE OF WORKS


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3rd review batch 7

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