Qualify Brazing Procedure Based On Groove Welds?
Qualify Brazing Procedure Based On Groove Welds?
(OP)
We have a customer who specifically asked for a repair using a TIG arc braze method on carbon steel. The scope of the repair is to buildup a thin (< 0.125") layer on one face of a CrMo (4130 normalized) machined housing then finish machine the surfaced area to final dimension. Either Alum bronze or silicon bronze filler will be used. In use, the new surface will be in compression and will experience very low static operating loads. Presumably, the point is to buildout the surface without need for a high temp post weld stress relief and risk distortions to critical dims which exist elsewhere in the equipment. Temper beading was discussed and dismissed since the intended additional surface layer is so thin.
Since all we are really doing is a surfacing operation, I feel inclined to NOT qualify an arc brazing procedure IAW ASME Sect IX QB100 which does not address surfacing, but rather to to treat this as a "buildup" and perform groove weld tests and qualify IAW QW-202.3
Am I correct in this thinking? Opinions please and thankyou.
Since all we are really doing is a surfacing operation, I feel inclined to NOT qualify an arc brazing procedure IAW ASME Sect IX QB100 which does not address surfacing, but rather to to treat this as a "buildup" and perform groove weld tests and qualify IAW QW-202.3
Am I correct in this thinking? Opinions please and thankyou.





RE: Qualify Brazing Procedure Based On Groove Welds?
RE: Qualify Brazing Procedure Based On Groove Welds?
Since this is depositing braze metal on a steel substrate (similar to a weld overlay except with braze metal), I would perform a mock-up by following a brazing procedure. Once the mock-up is completed, I would cross section the mock-up for metallographic examination to evaluate the bond integrity of the braze metal and surrounding 4130 BM.
RE: Qualify Brazing Procedure Based On Groove Welds?
Also would a preheat of about 350-400 deg F be advisable?
RE: Qualify Brazing Procedure Based On Groove Welds?
Preheat should be used just like fusion welding. Brazing results in a chemical bond and heat is used so the bond integrity and steel BM should be evaluated using a mock-up.
RE: Qualify Brazing Procedure Based On Groove Welds?