EFFECT OF INCLUSION AND BORON ON COLD CRACKING SUSCEPTIBILITY IN HSLA STEELS

With the help of transverse implant butt joint test and constant load hydrogen embrittlement test the cold cracking susceptibility of high-strength low-alloy (HSLA) steels was investigated.Experimental results showed that the inclusion in the steel will act as the trap for hydrogen and absorb so much hydrogen that the accumulation of hydrogen at grain boundaries will be lowered.Thus,within the scope of the experiments performed,cold cracking susceptibility will decrease with the increasing of inclusions.Boron will raise the hardenability of steel and make hydrogen accumulated at grain boundaries,resulting in higher susceptibility and weakened grain boundary.An important way to check the cold cracking susceptibility was therefore to maintain a suitable inclusion content in the grains and to reduce the boron content in steel as far as possible.