低碳贝氏体钢Q690D低屈强比研究  

Research on low yield strength ratio of low carbon bainite steel Q690D

作　　者：王新钢 Wang Xingang(Medium Plate Factory of Handan Iron and Steel Co.,Ltd.,Handan 056015,Hebei)

机构地区：[1]邯郸钢铁有限责任公司中板厂,河北邯郸056015

出　　处：《河北冶金》2025年第2期32-36,51,共6页Hebei Metallurgy

摘　　要：采用低碳微合金化成分设计、TMCP+低温回火工艺开发了低屈强比、低成本的Q690D钢。通过对比不同终轧温度、终冷温度和回火温度下低碳贝氏体钢Q690D屈强比和微观组织的变化,研究了影响其屈强比的主要因素及作用机制,为低碳高强度钢的开发提供了参考依据。研究发现,终轧温度在810~830℃,终冷温度在300~400℃时,钢板的热轧态屈强比最低,此外通过合适的回火工艺,控制贝氏体形貌和析出相的比例,使得软相和硬相合理搭配,钢板可获得良好的屈强比和综合力学性能。随着回火温度升高,钢板的屈强比呈先上升后下降的变化趋势,屈服强度较热轧态明显升高,而抗拉强度下降,韧性及塑性明显改善,但升高到一定程度,强度出现极速下降。该工艺减少了大量昂贵合金的加入,降低了成本,并且可以进行大批量生产,有力地提升了高强钢产品的市场竞争力。Q690D steel with low yield to strength ratio and low cost was developed using low-carbon microalloying composition design and TMCP+low-temperature tempering process.By comparing the changes in yield ratio and microstructure of low-carbon bainitic steel Q690D at different final rolling temperatures,final cooling temperatures,and tempering temperatures,the main factors and mechanisms affecting its yield ratio were studied,providing a reference for the development of low-carbon high-strength steel.Research has found that when the final rolling temperature is between 810~830℃and the final cooling temperature is between 300~400℃,the hot-rolled yield to strength ratio of the steel plate is the lowest.In addition,by controlling the bainite morphology and the proportion of precipitated phases through appropriate tempering processes,the soft and hard phases can be reasonably matched,and the steel plate can achieve good yield to strength ratio and comprehensive mechanical properties.The yield-tensile strength ratio of steel plates shows a trend of first increasing and then decreasing with the increase of tempering temperature.The yield strength increases significantly compared to the hot-rolled state,while the tensile strength decreases.The toughness and plasticity are significantly improved,but when it reaches a certain level,the strength decreases rapidly.This process reduces the addition of a large amount of expensive alloys,lowers costs,and can now be produced in large quantities,effectively enhancing the market competitiveness of high-strength steel products.

关 键 词：Q690D 贝氏体 屈服强度 抗拉强度 屈强比 

分 类 号：TG142.1[一般工业技术—材料科学与工程]