新型MG700高强锚杆用钢控轧控冷工艺研究
Research on the controlled rolling and controlled colling processes of steel for new MG700 high-strength anchor steel
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摘要: 基于热力模拟实验及相变实验,设计了钒微合金化MG700高强锚杆钢的合理控制轧制及控制冷却工艺,具体为:采用970~1 050 ℃进行粗中轧、800~840 ℃进行精轧的控制轧制工艺,以及采用中轧和精轧之间穿水冷却,控制终冷温度820~850 ℃、精轧后空冷的控制冷却工艺。上述控轧控冷工艺工业试生产结果表明,MG700锚杆钢的屈服强度稳定为720~760 MPa,抗拉强度稳定为885~925 MPa,断后延伸率稳定为17.5%~19.0%,综合力学性能优良。MG700锚杆钢的微观组织以铁素体和珠光体为主,铁素体晶粒直径介于0.60~13.64 μm之间,平均直径约为3.86 μm。研发的新型MG700高强锚杆钢力学性能及微观组织特征满足煤炭行业锚杆用钢的相关标准,可为同类产品的开发提供理论支撑和实践经验。Abstract: Based on the thermal simulation and phase transformation tests, the reasonably controlled rolling and controlled cooling processes of vanadium microalloyed MG700 high-strength anchor steel were designed. The details were as follows. For the controlled rolling processes, rough and intermediate rolling at 970~1 050 ℃ and finishing rolling at 800~840 ℃ were adopted. For the controlled cooling processes, water cooling was adopted between intermediate rolling and finishing rolling, the final cooling temperature was controlled at 820~850 ℃ and air cooling was used after finishing rolling. The above industrial trial results showed that the yield strength of MG700 anchor steel was stable at 720~760 MPa, its tensile strength was stable at 885~925 MPa, its elongation after fracture was stable at 17.5%~19.0% so that its comprehensive mechanical properties were excellent. The microstructure of MG700 anchor steel was mainly composed of ferrite and pearlite. The range of ferrite grain diameter was between 0.60 μm and 13.64 μm with an average diameter of about 3.86 μm. The mechanical properties and microstructure characteristics of the newly developed MG700 high-strength anchor steel met the requirements of the relevant standards for anchor steel in the coal industry, which could provide theoretical support and practical experiences for the development of similar products.