【摘要】 采用φ6.50 mm的ER70S-6双相钢盘条制备的8.8级M6×30全牙六角螺栓,铁素体晶粒尺寸约8.2μm,马氏体体积分数为11.5%。研究双相钢盘条制备螺栓过程中的力学性能变化规律,结果表明:双相钢盘条室温力学性能稳定,自然时效略增加盘条的塑性。盘条经大于22%的总压缩率拉拔后,抗拉强度约800 MPa,硬度达到螺栓要求,但塑性不能满足制备螺栓的要求。拉拔后成品丝的冷镦性能好,最大压缩变形抗力增加,但对拉拔量不敏感。冷镦后螺栓头部硬度比成品丝高,螺栓杆部硬度急剧降低。ER70S-6双相钢盘条制备8.8级螺栓需要成品丝的抗拉强度至少为880 MPa。电镀和自然时效不影响螺栓的性能。更多还原

【Abstract】 Diameter 6.50 mm ER70S-6 dual phase steel wire rod is adopted to produce 8.8 grade M6×30 full thread hex bolt,grain size of ferrite is about 8.2 μm,volume fraction of martensite is about 11.5%.The mechanical properties changing law of dual phase steel wire rod in the process of producing bolt is researched,results show that: the mechanical properties of dual phase steel wire rod at room temperature is stable,the plasticity of wire rod is improved slightly after natural aging.The tensile strength of wire rod is about 800 MPa after it is drawn with 22% total compressibility,hardness reaches requirements of bolt,but plasticity can’t meet requirements of bolt production.The cold heading properties of finished wire after drawn is good,the maximum compressive deformation resistance of the drawn wire increased,but it was insensitive to the area reduction.Hardness of the bolt head was increased,and the hardness of the bolt shank was decreased drastically.For ER70S-6 dual phase steel wire rod,the minimum strength of finished wire to meet the requirement of 8.8 grade bolt is 880 MPa.Natural aging and electroplating has little influence on the properties of the bolt.更多还原