Stub tube with header were heat treated in furnace. I wonder only 30 c in different of preheat tempature, 80 series preheat to 121c and 90 series need 30 c more, will result in serious delay cracking. It is difficult to tell preheat issue or PWHT issue is root cause of crack.
What is your opinion about root cause of leakage in stub tube weldment during hydrostatic test. Improper fillers(80 or 90series) have different preheat temperature. It sounds inadequate preheat temperature that 90 series and 80 series mixed passes in weldment only by preheat to 121C. Is...
We grid the surface up to #600. However the physical shape of stub tube weldment on header are complex due to 5 weld passes. Actually we also pick up high readings without respect to average reagings.
Yes, We use portable Leeb rebound hardness tester to measure the surface hardness of stub weldment in header. However the measured hardness readings were varied from 150 Hb to 250Hb by different person at same position. I think the readings strongly affected by man's skill and the topography...
Yes, you are correct. However, The PWHT records can not be trusted now. The headers with stubs are new one fabricated in shop. During hydrostatic test, some leakages were found in stub weldment. The problem is how to check Other headers with stubs have PWHT issues or not. Can we check by...
Documents shown header with stubs are subject to PWHT in overseas. However, abnormal microhardness value shows PWHT procedure is not good as we expected. Can not sure other headers with stub weld have these issues or not. Can I measure surface hardness by Leeb equipment after grinding stub...
Thanks reply.
Actually, stub tube leakage was occurred in hydrostatic test. May be cold crack was a reason to fail. In question 3, sample taken to show 350Hv is higher than I expected. The microhardness of weldment is usually ranged in 180-230Hv after PWHT. The parent material of SA213 T12...
Hello, I am new in this forum. I have welding issues listed below. Is there any comment I will appreciate.
1. There are 5 weld passes to joint stub tube to header with materials of SA213-T12 and SA335-P12 in pressure parts of power plant. E8016 electrodes were used in the root pass, second...
