Heat treatment for P1 to P4 non-pressure part welding
Heat treatment for P1 to P4 non-pressure part welding
(OP)
Our field is going to weld a new trunnion to an existing trunnion to lift a vessel. Please see the sketch.
I think preheat is good enough without PWHT. Am I correct ?
I think preheat is good enough without PWHT. Am I correct ?





RE: Heat treatment for P1 to P4 non-pressure part welding
RE: Heat treatment for P1 to P4 non-pressure part welding
RE: Heat treatment for P1 to P4 non-pressure part welding
RE: Heat treatment for P1 to P4 non-pressure part welding
RE: Heat treatment for P1 to P4 non-pressure part welding
RE: Heat treatment for P1 to P4 non-pressure part welding
I would forgo the 300 deg F post heat and perform PWHT because of the P-No 4 base material. Frankly, since this is a nonpressure part application you can do as you please. Just trying to provide good welding recommendations.
RE: Heat treatment for P1 to P4 non-pressure part welding
RE: Heat treatment for P1 to P4 non-pressure part welding
If you do not PWHT, I would recommend buttering the 45mm thick P4 material with the above stated electrodes (2 layes minimum) prior to making the strength joint to prevent laminar tearing of the P4 plate material due to the high residual welding stress applied in the weakest Z-direction of the plate. Preheat at 350 F min. Dehydrogenation PWHT would be recommended, but I assume that you will not do so as this step is not musch less expensive than a stress relieving PWHT.
RE: Heat treatment for P1 to P4 non-pressure part welding
Please explain.
This is really getting to be a scary world. We are preheating , and PWHT the crap out of a detail that appears, to me, to be destined to fail, and nobody says a word about the whole detail. We know nothing about the materials involved, essentially nothing about the existing conditions, welds and their sizes, dimensions, loads, etc. etc. Then, the OP’er is going to weld a new trunnion on the outside of the side/end plate of an existing trunnion. If the proportions of his sketch are anywhere near accurate, he is at least doubling the cantilever lever arm for the trunnion, so I trust he is halving the load to be lifted. Then he is welding the new trunnion onto a side/end pl. which is really only intended to keep the cable from slipping off the trunnion, so except by ASME standards, it may not be CJP welded to the round trunnion. In any case the side/end pl. should be checked for lamellar tearing after the new full pen. weld because of how restrained that joint is, through plate. Ah... Stanweld did mention that, after I started this post. Then move back to the wall of the vessel, double the moment on the trunnion, and check that existing weld. It was not likely designed for double the moment, whatever the margin of safety used. I’d wait to heat treat this until after they try to lift it. The pieces will fit in a much smaller heat treating furnace.
RE: Heat treatment for P1 to P4 non-pressure part welding
RE: Heat treatment for P1 to P4 non-pressure part welding
I’m glad you had that all handled, my hat’s off to you, and my apologies for doubting. I’ll sleep better tonight, knowing that.
Good Luck
RE: Heat treatment for P1 to P4 non-pressure part welding
RE: Heat treatment for P1 to P4 non-pressure part welding