Hot Straining Embrittlement of Bond in Welded Joint (3rd Report)

Effects of Heat Input, Preheat Temperature and Stress Relief Heating on the Embrittlment

Abstract

In the previous paper, the authors have proposed a new test (the so called BNP test) to evaluate the susceptibility of bond to hot straining embrittlement.
In this paper, effects of welding conditions on the degree of the embrittlement have been investigated by using the BNP test. The test have been carried out on the bond in HT80, A533 and SM50 steels.
Main results can be summarized as follows.
(1) The degree of hot straining embrittlement of bond (ΔTrs) is markedly dependent on heat input. Generally speaking, ΔTrs increases with heat input.
(2) Preheat and interpass temperatures have a considerable effect on the transition temperature (Trs) as shown in Fig.9.
(3) In the case of SM50 and base metal of HT80, annealing has a beneficial effect, but in the case of bond in A533 and HT80 steels, it is not always advantageous.