Preheat for welder tests 6

[sayee1]

If I am qualifying welders to say a WPS which requires 66 Deg C preheat for 38 mm thickness and above, and the welder qulification say is on a 38 mm plate/pipe, does the welde4r have to follow the preheat too. The reason I am asking is as per ASME section IX allows for not doing preheating/PWHT for the welder qualification test coupen even if the WPS needs so, but I could not find anything in D 1.1 Thanks and regards
Sayee Prasad R
Ph: 0097143968906
Mob: 00971507682668

 

[Rjeffery]

The Welder is qualifying to a specific welding procedure using base material, filler metal ect as the essential variables. If one of these variables is a preheat temperature then the base material must be preheated.

 

[sayee1]

Preheat is an essential variable for the WPS but not for the WPQ, so does it mean that I need n ot preheat for the welders test? Thanks and regards
Sayee Prasad R
Ph: 0097143968906
Mob: 00971507682668

 

[Rjeffery]

If he performs the welder's qualification test without preheat, successfully, then he has qualified a new WPS!

 

[GRoberts]

If you are using D1.1, you can write a prequalified WPS that can specify exactly what you want your welders to do while welding their qualification test cupon. It never says in D1.1 that a WPS has to be used in the field, you can write it just for qualification purposes. The place I used to work had all thier welder qualification WPSes written up this way for the standard welder tests that were taken.

 

[sayee1]

Roberts/Jeffery,
Please bear with me. ASME section IX very clearly states that all other essential variables except preheat and PWHT need to be followed for a we3lder qualification. Now D1.1 states around six or seven essential variables for welder qualification. Now the thing to remember is that if I am qualifying welders the preheat and PWHT are not going to affect the welder test in any way, I mean the welder skill is tested whether or not preheat and PWHT done. But then nowhere in AWS D1.1 it says that I am qualifying a welder to a qualified WPS. Imagine a situation where one welder is qualified to unlimited thickness because of the test coupen he ued but the WPS is qualified to x mm. Tomorrow if the WPS is rerqualified with an additional pQR to unlimited thickness, the welder can be used for unlimited without requalification right! Hope I am conveying what I want to ! Thanks and regards
Sayee Prasad R
Ph: 0097143968906
Mob: 00971507682668

 

[Rjeffery]

Sayee,

The intent of qualifying a welder is to prove he is competent to weld the base material, filler metal, joint type, thickness, position and the like. If the base material requires preheat in the 'real world' it should be required during qualification of the welder because we 'play as we practice' and you only want the 'essential variables to be his/her only restrictions. If preheat/postheat is not employed ad a flaw is found in the coupon/assembly is it the welder that failed or the lack of heat treatment causing the failure? The welder has every right to argue for failure of the procedure and not his proficiency/craftsmanship. They must be given every chance to pass not every hinderance to success.

 

[pipewelder1999]

Welders do not "qualify to" a wps. I have heard this stated manyy times and it is a very misleading statement that has caused much confusion. The essential variables for a welder qalification are separate from those from the WPS.

Preheat is NOT part of the test. If the test coupon is of a thickness or material that warrants preheat, preheat can be applied.

An organization has the right to modify the requirements for welder performance testing. None of the codes prohibit this. However someone should have the authority within that organization to do this.

As far as the above mentioned issue regarding the exception to Preheat and PWHT for WPQ, that is very true but I would like to add that similar statements are made in regards to base metals. A welder can qualify on carbon steel with er-70s-2 GTAW without purge and be qualified to weld 304 SS with the same essential variables.

Have a nice day
Gerald Austin
Iuka, Mississippi

http://www.weldinginspectionsvcs.com

 

[pandithan]

preheat is not essential variable for welder qualification
1, can be qualified with radioghraphic examination
2, bend test

it is a good engineering practice to preheat cs above certain thick

 

[rkg]

1. As far as code requirements are concerned, Pre-heat and PWHT are not necessary to be applied for Welder Qualification

2. At the same time, care must be taken while handling materials/conditions that may adversely affect the results of the Welder Qualification test. For example, consider the case of Welder Qualification by bend tests on thick Carbon Steel or Low Alloy Steels. Weld and HAZ in some of such cases may fail during bend test in absence of Pre-heat and/or PWHT.