Performance qual. min. thickness limitation 2

[hakkik]

Is there a minimum thickness limit for qualified weld metal thickness (groove weld, ASME BPVC Sec IX)

let's say welder tested from 10 mm thk plate. What is the qualification range for welder

10mm to 20mm or 0mm to 20 mm

thanks in advance

 

[metengr]

Look at Section IX, Table QW-452.1 for one welder

minimum - is thickness of weld metal in the coupon

maximum - is 2 x the weld metal thickness above

 

[hakkik]

I looked trough the table and i think it is a bit confusing. One column lists actual weld deposit thk. other lists the range as maximum thk. I think there is no minimum. Any other toughts or maybe offical interpretation

 

[metengr]

What was the thickness deposited on the 10mm coupon? Was it a 10mm groove weld? If so, the welder is qualified to deposit 10mm to 20mm.

 

[hakkik]

Why range is 10 to 20? this part is not clear for me. Table says nothing about minimum weld deposit thk. unlike QW-451.1

if test coupon weld deposit thk. is t than max. weld deposit thk. is 2t. It is clear but no info about minimum thk.

if test coupon weld deposit is t>13 than there is no upper thk. limit. Again no info about minimum thk.

I need code referance to convince myself that test coupon weld deposit thk. is the lower limit for the welder.

Qualified procedure limits the welder but performance test says nothing about min. thk.

when i search trough internet i found this site

http://www.gowelding.com/wp/asme.htm

" The main advantages of ASME welder approval tests are:-
• There is no minimum parent thickness, only maximums, and they are applied to the deposited thickness of the weld not the parent metal thickness.
• There is no upper limit on diameter approval, only a lower limit.
• Any butt weld approval will qualify all fillet weld sizes on any parent metal thickness. {Unfortunately unlike EN287 a butt weld carried out in the flat position will not qualify a fillet weld in the conventional horizontal position, to qualify this your butt weld approval must include the horizontal position}. "

 

[stanweld]

I must disagree with the statement that QW-452.1(b) regarding the minimum thickness qualified. The minimum thickness is not defined; only the "Thickness,t, of Weld Metal in the Coupon" and "Thickness of Weld Metal Qualified" as either 2t or Maximum to be welded if the welder qualifies on 1/2" and over with a minimum of 3 passes. If the minimum thickness is the thickness deposited inthe coupon, then for the past 40 years the Industry (Pressure Vessel Manufacturers, Boiler Manufacturers and Assemblers and Pipe fabricators and Contractors have not been qualifying welders correctly.

 

[metengr]

stanweld, I would agree with your statement and gave you a star for clarification. After reviewing the information in our program, all we state is maximum qualfied thickness deposited for performance because the WPS bounds the min to max.

 

[hakkik]

thanks for the clarification stanweld