Requirements of QW-283 - Welds With Buttering

[sushildwivedi16]

Dear All,

One of the equipment under fabrication in our workshop, requires buttering in order to weld a Stainless Steel gasket. The joint details are as mentioned below and needs PQR as per QW-283.

Base Metal is P No. 4 (SA 182 F11 Cl. 2). Thickness is 250 mm. Buttering of 5 mm thickness shall be done with SMAW ENiCrFe-3. After buttering the P4 shall be subjected to PWHT and subsequently SS 321 gasket shall be welded to buttered area with fillet of 6 mm using GTAW ERNiCr-3. No PWHT shall be done after fillet welding. The thickness of SS 321 to be welded to buttered area is 15 mm.

My query is with respect to the base metal thickness of P4 to be used for qualificaion.

As per QW-283 of ASME Sec. IX

"The variables for the buttering and for the subsequent weld shall be in accordance with QW-250, except that QW-409.1 shall be an essential variable for the welding process(es) used to complete the weld when the minimum buttering thickness is less than 3/16 in. (5 mm). Mechanical testing of the completed weldment shall be in accordance with QW-202.2(a)."

Should the thickness of the P4 be 188 mm minimum to satisfy the requirements of Table QW-451.1 ? OR

Does ASME Sec. IX, in this case, permit the use of QW-202.4 (b) (2) to meet the thickness requirement wherein the P4 thickness can be 38 mm or more (but need not be 188 mm) to qualify the welding of above joint

 

[metengr]

If you are invoking QW-283, the coupon thickness should be 192mm, to qualify to 1.3T = 250mm BM thickness

This would be a groove weld buttered to at least 5mm thickness, PWHT and completed with different filler metal requiring the entire thickness of the weld coupon be welded per Note 6 in QW-451.1. Coupon thickness to have 250mm is 250/1.3 = 192mm

Invoking QW-202.4b would not apply to the above because you are not joining to dissimilar base materials.

I would suggest you approach this as a CRO qualification. See QW-214.