Alu. Backing?

Date 12-26-2008 01:15

I have been a certifed cwi for the past eight years and have not been very active with ASME-IX. The notes on the drawing are to comply with ASME-IX .We have a new cwi at work and he is qualifying welders on 316L single groove {cjp} base metal .1875 thick using a .50in Alu. plate for backing that covers half of the coupon.There is nothing in the WPS that includes any backing of any kind. I have studied AWS D1.6 and looked closely at ASME IX and can find nothing that warrants using Alu. or any other type of backing if it is not listed on the WPS. Also the WPS has not been signed or stamped. I thought that was mandatory! Would someone please send me some feedback. Thank you; no1welder

By pipewelder_1999 (****)

Date 12-26-2008 14:45

The backing material composition is typically a non-esssential variable or in many cases not even addressed as a variable. Though the standard form may list the "backing Material Type" it may not be a variable for that process.

Take a look at the QW-255 Table for the process you are speaking about. It will refer you to the QW 4xx paragraphs that apply.

Take a look at QW 103.2 regarding signatures.

By 803056

Date 12-29-2008 17:42

While backing is a nonessential variable, it does have to be described by the WPS.

All essential and nonessential variables have to be addressed by the WPS.

Under the space for "backing" on the WPS, the verbiage: "With or without" hardly meets the needs of the welder. I would expect the type of backing to be listed and described.

Best regards - Al

By pipewelder_1999 (****)

Date 12-30-2008 04:37

Though the backing material composition may be "Expected" to be listed. It just isn't required by Sec IX.

I agree that all essential and non-essential variables need to be addressed. Composition of the backing just isn't any type of variable for many processes.

The variable for change in composition 402.5 will apply to GTAW and PAW welds but for other processes it just addition or deletion 402.4.

Again the requirements of the code may not be all that is needed for a good quality system. Its just a start.

Have a good one.

Gerald

By 803056

Date 12-30-2008 13:51

The conversation now switches from the "need of information" to "minimum code requirements".

As you infer, there is a difference between the two.

Happy holidays - Al

By pipewelder_1999 (****)

Date 12-30-2008 14:05

I was trying to give information related to his original question that contained " I thought that was mandatory! " and thus was in the context of "code requirements".

The statement "While backing is a nonessential variable, it does have to be described by the WPS" led me to believe you were indicating the type (composition) of the backing had to be described on the WPS. And I do agree that that is useful information for the welder. It is not something that must be addressed on the WPS except for GTAW and PAW.

Didn't really intend to switch anything but now the post will have some of each types of information.

If someone were to just use an ASME Correct WPS they could use galvanized steel as a backing for SS. A very bad idea, but still "code compliant". A good reason for drawings, welding standards, and other associated engineering documents. Or how about the old standby blocks of carbon! Works great but what does it do for that 1st pass carbon content.

Have a nice day

Gerald
Iuka Ms

By 803056

Date 12-30-2008 14:47

As always, very good points Gerald.

What we would "like to see" included in a WPS is not always "required" by the applicable code.

Best regards - Al