控轧控冷工艺对高强度锚杆钢组织和性能的影响

随着矿井深度的增加,对锚杆支护强韧性的要求越来越高,为了应对这一情况,需要研发出更高强度的锚杆钢。利用锚杆钢研究了轧制工艺、冷却工艺与珠光体、铁素体相比例,析出相析出行为及力学性能的关系。研究结果表明,在中轧后、精轧前采用适当水冷+回复段处理的复合工艺可使晶粒更细小、组织更均匀。对超高强度锚杆钢进行热压缩变形试验,由热模拟试验结果确定相转变温度为A_c1=737 ℃、A_c3=886 ℃。最终筛选出入精轧温度为810 ℃、回复段温度为800 ℃时,可获得的晶粒尺寸达4 μm,珠光体体积分数为66.8%,铁素体体积分数为33.2%,珠光体片层间距达200 nm;另外调整V、Cr、N等析出以提高锚杆钢的强韧性,较低的回复温度有利于细小、弥散、V(C/N)析出相的析出,V(C/N)的析出可进一步改善锚杆钢的力学性能。由该控轧控冷工艺轧制的锚杆钢屈服强度为780 MPa、抗拉强度为930 MPa、硬度为291HV、伸长率为20%。

Effect of controlled rolling and controlled cooling process on microstructure and properties of high strength anchor steel

As the depth of mine increases, the requirements for strength and toughness of anchor steel bolt support are getting higher and higher. In order to cope with this situation, it is necessary to develop higher-strength anchor steel. The relationship between rolling process, cooling process, pearlite and ferrite phase proportion, precipitation behavior and mechanical properties of anchor steel was studied. The research results show that the composite process of appropriate water cooling and recovery section treatment after intermediate rolling and before finishing rolling can make the grains smaller and the structure more uniform. The hot compression deformation test was carried out on the ultra-high-strength anchor steel, and the phase transition temperatures were determined to be A_c1=737 ℃ and A_c3=886 ℃ from the results of thermal simulation test. In the final screening, when the finishing rolling temperature was 810 ℃, and the temperature in the recovery section was 800 ℃, the obtained grains reached 4 μm, the pearlite volume fraction was 66.8%, the ferrite volume fraction was 33.2% and the pearlite lamella spacing reached 200 nm. In addition, adjusting the precipitation of V, Cr, N, etc. to improve the strength and toughness of anchor steel, the lower recovery temperature is conducive to the precipitation of fine, dispersed, V(C/N) precipitates, and the precipitation can further improve the mechanical properties of anchor steel. The anchor steel rolled by this controlled rolling and controlled cooling process has yield strength of 780 MPa, tensile strength of 930 MPa, hardness of 291HV, and elongation of 20%.