【摘要】 本文以A3废钢为主要原料,添加Si、Mn、Cr和一种廉价的金属等多种合金元素,加入少量Mo、稀土进行微合金化和变质处理,在中频炉冶炼、潮模砂型的条件下,制得10 mm×10 mm×55 mm无缺口冲击试样。经热处理后,获得了以准贝氏体为基体综合性能优良的合金钢。该钢经过奥氏体化后空冷,再经回火处理,分别测试了空冷、回火处理后试样的洛氏硬度、冲击韧性,并在Olympus和扫描电子显微镜(SEM)下观察了其组织形态与断口形貌。试验结果表明,试样经920℃保温1 h奥氏体化后空冷、300℃保温2 h回火后得到较好的硬度与冲击韧性的匹配,硬度达到HRC34,冲击韧性高于240 J/cm2,金相组织以准贝氏体为主,含有少量的残余奥氏体。实验证明该钢是一种热处理工艺简便、成本低、可以代替调质钢、提高经济效益的新型钢种。更多还原

【Abstract】 Low alloy bainitic cast steel to A3 as the main raw material,containing suitable Si,Mn,Cr,a sort of cheapness metal and trace amount of Mo and using rare earth(RE) to microalloying and modification,smelt in intermediate frequency furnace;Cast 10 mm× 10 mm× 55 mm without notched impact specimen in green sand molding.The sample could obtained meta-bainitic as matrix excellent performance alloy after heat treatment.The steel air-cooled after austenitic,and then drawing temper.The hardness and impact toughness were tested,and its microstructure and fracture morphology were observed by.electron metallography and scanning electron microscopy(SEM).Test results showed that a good mechanical performance(impact toughness≥240 J/cm2,hardness≥34 HRC) of bainite structure can be obtained by tempered at 300 ℃ for 2 h when it is cooled by air at 920 ℃×1 h.The results show that the microstructure consisting of meta-bainite and a few residual austenites can be obtained through the optimum quenching,The experiment proves this steel has a simple production process,less addition of valuable alloy and low production cost.It could substitute for quenched and tempered steel and increase economic performance.更多还原