A Study on Submerged Arc Welding with bonded Fluxes (7th Report)

Stress Corrosion Cracking on 80kg/mm High Strength Steel in H₂S

Abstract

The susceptibility to stress corrosion cracking in hydrogen sulfide-water system was studies on two commercial 80 kg/mm² high strength steel plates and some weld metals. Here weld metals were prepared by submerged arc welding method using experimental bonded fluxes and commercial wires for low alloy steels. The susceptibility to cracking was tested by failure time on specimens loaded in tension and exposed to 0.5% acetic acid solution to which hydrogen sulfide was added. Furthermore a experiment on hydrogen embrittlement was conducted on commercial 80 kg/mm² high strength steel plates. Hydrogen sulfide-water system was used in this experiment too.
The test results were as follows :
(1) Poor resistance of test materials to cracking is accompanied by relatively high nickel content (0-2% Ni in test meterials).
(2) Lower susceptibility of annealed (600°C) weld metals was attained by increasing Molybdenium and Chromium content up to about 2%. (Test materials contain about up to 5% Cr and 2% MO)
(3) The test steel plate which was relatively susceptible to cracking was seemed to be more sensitive to hydrogen embrittlement than the less susceptible one.