齿轮轴用SAE8620热轧盘条的开发
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摘要
采用铁水→转炉冶炼→LF炉精炼→RH真空处理→320 mm×425 mm连铸→开坯轧制→轧制坯精整、检验→高线轧制生产工艺流程和合理的化学成分设计,成功开发了SAE8620热轧盘条,同时研究了SAE8620钢过冷奥氏体连续冷却相变行为。结果表明:SAE8620盘条具有优异的热轧态组织和性能,热处理性能满足GB/T 3077《合金结构钢》中的20CrNiMo钢性能要求。末端淬透性试验结果满足GB/T 5216—2004《保证淬透性结构钢》中的20CrNiMoH性能要求。Cr、Mo、Ni等合金元素的加入有效的抑制过冷奥氏体向铁素体和珠光体转变,促进贝氏体、马氏体转变;当冷却速率大于1.0℃/s时,相变组织中开始出现贝氏体,且随着冷却速率的增大比例急剧增加;当冷却速率大于5.0℃/s时,相变组织中开始出现马氏体。
Hot-rolled wire rod SAE8620 has been successfully developed by using the process flow:converter smelting→LF refining→RH vacuum treatment→continuous casting(casting slab size:320 mm×425 mm)→breakdown rolling→finishing and checking→high speed wire rod rolling and reasonable chemical composition design. At the same time,the over-cooling austenite continuous cooling transformation behavior of steel SAE8620 has been studied. The results show that the rod SAE8620 has excellent hot-rolled microstructure and properties,and the heat treatment performance meets the requirements of steel 20 CrNiMo in accordance with alloy structuresteels GB/T 3077,the end hardenability test results meet the requirements of 20CrNiMoH in accordance with structural steels subject to end-quench hardenability requirement GB/T 5216-2004. The addition of Cr,Mo,and Ni alloy elements can effectively inhibit the transformation of over-cooling austenite to ferrite and pearlite,and promote the transformation of bainite and martensite. When the cooling rate is greater than 1.0 ℃/s,bainite will begin to form in the metallographic structure,and the proportion has increased dramatically with the increase of cooling rate; when the cooling rate is greater than 5.0 ℃/s,martensitic will form in the metallographic structure.
Hot-rolled wire rod SAE8620 has been successfully developed by using the process flow:converter smelting→LF refining→RH vacuum treatment→continuous casting(casting slab size:320 mm×425 mm)→breakdown rolling→finishing and checking→high speed wire rod rolling and reasonable chemical composition design. At the same time,the over-cooling austenite continuous cooling transformation behavior of steel SAE8620 has been studied. The results show that the rod SAE8620 has excellent hot-rolled microstructure and properties,and the heat treatment performance meets the requirements of steel 20 CrNiMo in accordance with alloy structuresteels GB/T 3077,the end hardenability test results meet the requirements of 20CrNiMoH in accordance with structural steels subject to end-quench hardenability requirement GB/T 5216-2004. The addition of Cr,Mo,and Ni alloy elements can effectively inhibit the transformation of over-cooling austenite to ferrite and pearlite,and promote the transformation of bainite and martensite. When the cooling rate is greater than 1.0 ℃/s,bainite will begin to form in the metallographic structure,and the proportion has increased dramatically with the increase of cooling rate; when the cooling rate is greater than 5.0 ℃/s,martensitic will form in the metallographic structure.
引文
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[2]王刚,林贵明,周蕾.8622H齿轮钢的开发[J].中国冶金,2012,22(4):23.
[3]赵千水.本钢重载汽车齿轮用钢SAE8620H的研制[J].本钢技术,2013(5):10.
[4]徐咏梅,付才,齐欣.重载汽车齿轮钢8620H的组织与性能研究[J].一重技术,2005(5):23.
[5]周志伟,俞杰.齿轮用钢SAE8620H的研制[J].2011,39(4):11.
[6]李成良,黄远坚,温志红,等.合金元素Mo和V对模具钢组织性能的影响[J].金属材料与冶金工程,2017,45(Z1):5.
[7]王香彬,韦弦,孙斌,等.含Mo低碳贝氏体钢形变奥氏体连续冷却相变规律研究[J].河南冶金,2011,19(2):16.
[8]王伊敏,尹嘉明,郝丽萍,等.SAE8620H钢奥氏体连续冷却转变曲线[J].兵器材料科学与工程,2010,33(3):85.