PSB785精轧螺纹钢控冷轧制工艺实践

为使PSB785精轧螺纹钢筋强度与塑性相匹配,采用以下工艺:(1)钢坯加热出炉温度为960～1 020℃,开轧温度为970℃;(2)轧件进精轧机温度为850～890℃,钢筋的终轧温度为930～1 000℃,自回火温度为680～700℃;(3)上冷床温度为560～600℃。采用设计工艺生产的25,32 mm PSB785精轧螺纹钢筋的抗拉强度为1 021～1 055MPa,延伸率为8.5%～9.6%,金相组织为珠光体+铁素体,晶粒度为9.0～9.5级,穿水层为回火索氏体,穿水层深度为1.24～1.46 mm,符合GB/T 20065—2006《预应力混凝土用螺纹钢筋》,可满足用户的使用要求。

Practice of control-cooling rolling of PSB785 fine rolling spiral bar

In order to match PSB785 fine rolling spiral bar’s stress with its plasticity,below technology is used:(1) billet heating tapping temperature is 960~1 020 ℃,blooming temperature is 970 ℃;(2) the entering temperature is 850~890 ℃,spiral bar’s final rolling temperature is 930~1 000 ℃,self-tempering temperature is 680~700 ℃;(3) going-on-cooling-bed temperature is 560~600 ℃.The tensile strength of diameter 25 and 32 mm PSB785 fine rolling spiral bar based on above technology is 1 021~1 055 MPa,coefficient of extension is 8.5%~9.6%,metallographic structure is pearlite and ferrite,grain size is 9.0~9.5 grade,the quenching layer is tempering sorbite,the thickness of quenching layer is 1.24~1.46 mm,which meet GB/T 20065—2006 rolling spiral bar for pre-stressed concrete and satisfy customers’ needs.