淬火温度对超高强海工钢屈强比的影响

Effects of Quenching Temperature on Yield to Tensile Strength Ratio of Ultra High Strength Offshore Engineering Steel

为了研究淬火温度对超高强海工钢EH690屈强比的影响,开展了淬火+回火工艺试验,并对试验钢的力学性能及显微组织进行检验和观察分析。结果表明:试验钢在淬火温度不同而回火温度相同的情况下,随着淬火温度的降低,屈强比逐渐降低,尤其在经过840℃淬火后,屈强比较低并同时具有良好的力学性能,微观组织为回火马氏体+针状铁素体双相组织。硬相马氏体保证试验钢的强度和冲击韧性,而软相针状铁素体则保证试验钢具有相对较低的屈服点,进而降低了屈强比。

In order to study the effects of quenching temperature on yield to tensile strength ratio of ultra high strength offshore engineering steel EH690,quenching and tempering process test is performed,the mechanical properties is tested,the microstructure is observed and analysed.The results show that under the conditions of different quenching temperatures and same tempering temperature,the yield to tensile strength ratio of the test steel gradually decreases with the decrease of quenching temperature,especially the yield to tensile strength ratio is lower at quenching temperature of 840℃with good mechanical properties,and the test steel consists of dual phase microstructure of tempered matensite and acicular ferrite.The hard phase martensite ensures the strength and impact toughness,while the soft phase acicular ferrite guarantees the relatively lower yield point,which reduces the yield to tensile strength ratio.