We covered ASME certification in part 1 of this blog.
Shown in Fig. 2 is a picture of the cover of the AWS B2.2 specification for brazing certification. This, like the ASME certification spec, is a good document that can be used to help ensure good, high-quality torch-brazed piping systems. I’ve personally taught torch-brazing certification programs using this AWS B2.2 specification as part of that certification process. It is a very helpful tool in that process.
Torch-brazing qualification and certification is a process that must be taken very seriously, and those who pass such certification programs successfully should then know how to produce good-looking brazed joints exhibiting smooth, small, concave fillets with little if any brazing filler metal (BFM) run-off. Fig. 3 shows cross-sectional drawings of both good and bad brazed joints.
In Fig. 3a, the joint was properly heated, the torch being used to not only fill the joint but also to draw the molten BFM from the bottom to the top of the fitting to make a complete joint. This is evidenced by the small meniscus (fillet) at the top of the fitting, indicating that the molten BFM has been adequately pulled all the way through the joint by capillary action. In Fig. 3b, however, the torch brazer did not heat the joint properly in that he/she did not move the torch up the fitting so as to “draw” the molten BFM upward to fill the joint completely. Instead, the heat was kept near the bottom of the joint where the BFM was applied, resulting in excess BFM run-off at the bottom because capillary action was not able to fill the “colder” portion of the joint near the top of the fitting.
We will finish this discussion next time in part 3.