PWHT THICKNESS REQUIREMENTS ASME SECTION VIII DIV 1

[Sumit bhadakwad]

Hello Everyone ,

I am new here but very sure that i will get my answers from experts.
I am confused between UCS-56(d)(1) through (5) term "maximum material thickness " & UW-40(f)(1) through (6).

I really want to clear both this term .

Actually we are manufactured base frame of size 15mx5mx3m in H beam of size 305x30x118x20thk and in which different plate thickness plates used to weld on base frame.in which 105 mm thk plate highest in thickness. & i want to make PWHT cycle include all things like.

unrestricted heating rate up to .
Heating rate of maximum :-
Holding temperature
Soaking Time :
Cooling rate of maximum:-
Unrestricted cooling rate from

 

[weldstan]

Is the H beam subject to pressure? Or is it a structural attachment to a pressure part? Is the material carbon steel?

 

[Sumit bhadakwad]

Hello weldstan ,

It is actually base frame for air compressor , its material is CS[pre][/pre] IS2062 Gr.a.

yes it is structural attachment to pressure part .[pre][/pre]

 

[212197]

for determining nominal thickness pertaining to weld between non pressure to pressure parts, UW-40(f)(5)(f) is to be referred.
That says, thickness of weld at the point of attachment is nominal thk.
In your case what is the throat dimension of the fillet weld by which 105 mm thk is getting welded with pressure part.that could be the deciding number for determining soaking time.

Generally followed cycle for PWHT of CS MATERIAL

unrestricted heating rate up to . 300 DEGREE CEL.
Heating rate of maximum :- 50DEGREE CEL./HR
Holding temperature 610 TO 630 DEGREE CEL.
Soaking Time : EXPLAINED ABOVE. (2HRS+ 15 MIN.FOR EACH ADDITIONAL INCH OVER 2 INCH THK.
Cooling rate of maximum:- 50DEGREE CEL./HR

 

[212197]

I have assumed that joining of 105 thk plate is by fillet weld.

 

[Sumit bhadakwad]

Hello 212197 (Mechanical),

Thank for your valuable comments .

But its non pressure part its a structural component .

Pressure part not going to weld . pressure part just fitted by using nut & bolt.

 

[Sumit bhadakwad]

If you tell me what is the use of UW-40(f)(1) through (6) ?

And UCS-56(d)(1) through (5) term ?

By using this terms what we get .

Please tell me from where you got this values.

nrestricted heating rate up to . 300 DEGREE CEL.
Heating rate of maximum :- 50DEGREE CEL./HR
Holding temperature 610 TO 630 DEGREE CEL.
Soaking Time : EXPLAINED ABOVE. (2HRS+ 15 MIN.FOR EACH ADDITIONAL INCH OVER 2 INCH THK.
Cooling rate of maximum:- 50DEGREE CEL./HR

 

[weldstan]

Why are you using ASME VIII for PWHT? Per AWS D1.1 PWHT would not be required and only a 200F preheat would be r needed. But I assume that you believe the welds will be subject to cyclic loading, in which case, your proposed PWHT is fine.

 

[weldstan]

Repeating 212197, are the welds involved fillet welds? If so why PWHT? Compressors are out of the scope of ASME VIII.
































if so

 

[Sumit bhadakwad]

Hello weldstan ,

Its our customer requirement to do pwht as per section VIII that why doing PWHT.

They told us it is mandatory .

 

[212197]

Sumit,
reply to ur queries :

If you tell me what is the use of UW-40(f)(1) through (6) ?

reply - this clauses explain definition of nominal thickness for various weld configurations like butt weld/fillet weld/groove weld etc.

And UCS-56(d)(1) through (5) term ?
reply - limits for cooling/heating rate, furnace atmosphere etc. is defined. based on which one has to decide the cycle of heat treatment.

By using this terms what we get .


Please tell me from where you got this values.

reply- this is the cycle which we follow for CS material. this is broadly based on UCS 56.

 

[Sumit bhadakwad]

hello 212197 ,

Thank you so much.

1) As per UW-40(f)(1) through (6) , first we have to note in our job which type of joints are there .
then as per joint check nominal thickness of each weld joint & consider higher thickness for

Nominal thickness to calculate soaking time .

Am i right ?

2) In our job 105 higher thickness but its fillet joint , fillet size will be 75 mm, so as per fillet size we will calculate soaking time am i right ?

3) How to calculate unrestricted heating & cooling unrestricted rate ?

and where it given in ASME.

Thanks in advance.

 

[oknow]

Be sure to verify the thermocouples and temperature recorders are in current calibration status prior to placing the order.

Depending on several factors the HT Subcontractors will not fire up their oven for one item. Read UW-40(c)

 

[212197]

Replied as below :

1) As per UW-40(f)(1) through (6) , first we have to note in our job which type of joints are there .
then as per joint check nominal thickness of each weld joint & consider higher thickness for

Nominal thickness to calculate soaking time .

Am i right ?

2) In our job 105 higher thickness but its fillet joint , fillet size will be 75 mm, so as per fillet size we will calculate soaking time am i right ?
reply- as per UW40(f)(3), throat of fillet = nominal thk. i assume 75 is fillet leg. hence throat = o.707 x 75.

3) How to calculate unrestricted heating & cooling unrestricted rate ?

and where it given in ASME.
Reply - asme will give only guidelines/rules. generally metallurgist decided the rates. we follow 50DEGREE CEL./HR for CS pressure parts. u can refer attached EIL spec. for cycle of non preesure structural parts

 

[Sumit bhadakwad]

Hello 212197 ,

1) In our drawing below note given -and higher thickness is 105 mm.

( FOR PLATE TO PLATE WELDING, REFER WELDING FILLET VALUE TO BE 0.7 TIMES
OF MIN PLATE THIKNESS ).

2) 1) As per UW-40(f)(1) through (6) , first we have to note in our job which type of joints are there .
then as per joint check nominal thickness of each weld joint & consider higher thickness for

Nominal thickness to calculate soaking time .

Am i right ?

 

[212197]

Replied as below :

1) In our drawing below note given -and higher thickness is 105 mm.

( FOR PLATE TO PLATE WELDING, REFER WELDING FILLET VALUE TO BE 0.7 TIMES
OF MIN PLATE THIKNESS ).

Reply : fillet size is 75 mm. throat = 53 mm. so nominal thickness to decide soaking time = 53 mm.

2) 1) As per UW-40(f)(1) through (6) , first we have to note in our job which type of joints are there .
then as per joint check nominal thickness of each weld joint & consider higher thickness for

Nominal thickness to calculate soaking time .

Am i right
Reply : right.

 

[Sumit bhadakwad]

Dear 212197 ,

Hang god you clear all my dought for pwht.

Thank you very much for such a valuable advice.

So now as per my calculation final cycle will be .


unrestricted heating rate up to .300 DEGREE CEL.
Heating rate of maximum :- 109 DEGREE CEL/ h.
Holding temperature - 600 DEGREE CEL/.
Soaking Time : 120 min.
Cooling rate of maximum:- 68 DEGREE CEL/ h.
Unrestricted cooling rate from-300 DEGREE CEL/ h.

Am i right ?

 

[212197]

Soaking Time : 130 min
how u hv calculated heating & cooling rate?
rest is ok

 

[Sumit bhadakwad]

Hello 212197 ,

As per UW40(f)(3), throat of fillet = nominal thk. i assume 75 is fillet leg. hence throat = o.707 x 75=52 , nominal thk taken 52 , so heating rate is 109.

And for cooling rate 105 thk taken .

 

[212197]

soaking time depends on thickness/ throat.
heating & cooling rate do not depend on thickness/throat.
u need to follow heating & cooling rate mentioned in EIL specification which I have already shared.