夹杂物及硼对低合金高强钢焊接冷裂纹敏感性的影响
EFFECT OF INCLUSION AND BORON ON COLD CRACKING SUSCEPTIBILITY IN HSLA STEELS
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摘要: 本研究工作采用卧式对接插销试验和定载荷氢脆试验对低合金高强钢冷裂纹敏感性进行了探讨,从试验的结果可以认为:钢中的夹杂物可以作为氢的陷井,吸取更多的氢,因而降低了氢在晶界和局部的集积。所以,在本试验范围内,钢中的夹杂物越多,冷裂纹敏感性越能得到改善。含硼的钢,由于增加钢的淬硬性,因此提高了冷裂纹的敏感性。此外,硼还能促使氢在晶界集积,造成晶界脆弱。由上所述,使晶内存在适量的夹杂物和尽可能降低钢中的含硼量,可以作为改善对冷裂纹敏感性的重要手段。Abstract: 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.