合金工具钢S2盘条的开发
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摘要
通过80 kg真空感应炉试验及Gleeble 3800热模拟试验机测试了连续冷却相转变(CCT)曲线,设计了S2钢的化学成分(/%:0.63~0.69C,1.00~1.20Si,0.40~0.60Mn,0.20~0.40Cr,0.40~0.50Mo,0.15~0.25V,0.10~0.30Ni,0.010~0.030Nb,≤0.015P,≤0.010S),并进行120 t BOF-LF-VD-300 mm×390 mm方坯连铸-开坯-高线轧制-斯太尔摩控冷流程的工业性生产。通过铁水脱硫,铁水硫含量≤0.010%,BOF终点[C]0.10%~0.30%,[P]≤0.012%,钢水终点温度1 620~1 660℃,BOF出钢采用Si-Mn预脱氧,LF精炼渣(/%:8~10 MgO,44~45 CaO,5~10 SiO_2,25~35 Al_2O_3),LF精炼结束喂钙线,连铸钢水过热度≤25℃,拉速0.65 m/min和轧制控冷等工艺措施,成功开发了合金工具钢S2盘条。检验结果表明,Φ8 mm热轧盘条奥氏体晶粒度为8.5~9.0级,脱碳层厚度≤0.5%D,热轧盘条HRC硬度值50,同卷HRC硬度值波动小于6,各项性能满足技术要求。
By testing with a 80 kg vacuum induction furnace and measuring continuous cooling transformation(CCT)curves by using Gleeble 3800 hot simulation machine the chemical composition of steel S2(/% : 0. 63 ~0. 69 C, 1. 00 ~1. 20 Si,0. 40 ~ 0. 60 Mn,0. 20 ~ 0. 40 Cr, 0. 40 ~0. 50 Mo, 0.15 ~ 0. 25 V,0. 10 ~0. 30 Ni,0. 010 ~0. 030 Nb,≤0. 015 P, ≤0. 010 S) has been designed, and the commercial production by 120 t BOF-LF-VD-300 mm × 390 mm bloom casting-breakdown-high speed wire rolling-Stelmor control cooling process has been carried out. With the process measures including hot metal dephosphorization, sulphur content in metal ≤0. 010%, control of BOF end [C] 0. 10% ~0. 30%,end [P] ≤0. 012%, liquid end temperature 1 620 ~ 1 660℃, using Si-Mn pre-deoxidation in BOF tapping, LF refining slag(/%: 8 ~ 10 MgO, 44 ~45 CaO, 5 ~10 SiO_2,25 ~35 Al_2 O_3),feeding calcium wire at end of LF refining, overheating extent of casting liquid ≤25℃,casting speed 0. 65 m/min,and controlling cooling after rolling,the coil of alloy tool steel S2 is successfully developed. Examination results show that the each property index of Φ8 mm hot-rolled coil meets the requirement of technical specification, including the austenite grain size rating 8. 5 ~ 9. 0, the depth of decarburization layer≤0. 5%D, the HRC hardness value of hot-rolled coil 50 and the variation of HRC hardness value of same coil less than 6.
By testing with a 80 kg vacuum induction furnace and measuring continuous cooling transformation(CCT)curves by using Gleeble 3800 hot simulation machine the chemical composition of steel S2(/% : 0. 63 ~0. 69 C, 1. 00 ~1. 20 Si,0. 40 ~ 0. 60 Mn,0. 20 ~ 0. 40 Cr, 0. 40 ~0. 50 Mo, 0.15 ~ 0. 25 V,0. 10 ~0. 30 Ni,0. 010 ~0. 030 Nb,≤0. 015 P, ≤0. 010 S) has been designed, and the commercial production by 120 t BOF-LF-VD-300 mm × 390 mm bloom casting-breakdown-high speed wire rolling-Stelmor control cooling process has been carried out. With the process measures including hot metal dephosphorization, sulphur content in metal ≤0. 010%, control of BOF end [C] 0. 10% ~0. 30%,end [P] ≤0. 012%, liquid end temperature 1 620 ~ 1 660℃, using Si-Mn pre-deoxidation in BOF tapping, LF refining slag(/%: 8 ~ 10 MgO, 44 ~45 CaO, 5 ~10 SiO_2,25 ~35 Al_2 O_3),feeding calcium wire at end of LF refining, overheating extent of casting liquid ≤25℃,casting speed 0. 65 m/min,and controlling cooling after rolling,the coil of alloy tool steel S2 is successfully developed. Examination results show that the each property index of Φ8 mm hot-rolled coil meets the requirement of technical specification, including the austenite grain size rating 8. 5 ~ 9. 0, the depth of decarburization layer≤0. 5%D, the HRC hardness value of hot-rolled coil 50 and the variation of HRC hardness value of same coil less than 6.
引文
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[15]刘宗昌,计云萍,任慧平.贝氏体相变的过渡性特征[J].热处理,2014,29(5):24-31.
[16]张晓,刘国权,宋月鹏,等.淬火钢件冷却速度、显微组织和硬度分布的计算预报[J].钢铁研究学报,2007,19(12):49-52.
[2]Nomura M,Morimoto H and Toyama M.Calculation of Ferrite Decarburizing Depth,Considering Chemical Composition of Steel and Heating Condition[J].ISIJ International,2007,40(6);619-623.
[3]马志军,王鲁义,方元杰.60Si2MnA弹簧钢盘条脱碳层控制工艺的优化[J].特殊钢,2016,37(4):26-28.
[4]赵海民.高性能弹簧钢60Si2CrVA和38Si7高周和超高周疲劳破坏行为的研究[D].北京:钢铁研究总院,2008.
[5]徐少兵,吴建洲.国内外大方坯连铸机新技术发展综述[J].中国冶金,2008,18(4):1-6.
[6]黎建,陈天明,杨素波.转炉-大方坯连铸工艺生产轴承钢探讨[J].钢铁钒钛,2004,25(3):30-35.
[7]任勇强,谢振家,尚成嘉.低碳多相钢的组织调控与力学性能[J].北京科技大学学报,2013,35(5):592-600.
[8]韩安昌,林大为,邱昱斌.低碳结构用Nb-V和Nb-Ti复合微合金钢性能的比较[J].上海金属,2004,26(5):34-37.
[9]于庆波,孙莹,李子林,等.微量固溶Nb在钢中的作用[J].钢铁,2006,41(2):59-62.
[10]吴华林,王福明,李长荣,等.Nb-V复合弹簧钢60Si2CrVAT过冷奥氏体连续冷却转变[J].北京科技大学学报,2011,33(12):1463-1470.
[11]徐温崇,孙福玉.Nb-V微合金钢中Nb与V析出相的精细结构[J].金属学报,1983,19(6):29-118.
[12]朱晨,王伯健.钼及镍在不同钢种中作用的研究进展[J].热加工工艺,2009,38(24):36-38.
[13]朱平,赵亮.合工钢S2M脱碳特性与加热温度的关系[J].科技创新与应用,2015(19):126-127.
[14]冯贺滨,褚建东,吉学军.高速线材斯太尔摩控制冷却过程的数学模型[J].材料热处理学报,2000,21(1):44-49.
[15]刘宗昌,计云萍,任慧平.贝氏体相变的过渡性特征[J].热处理,2014,29(5):24-31.
[16]张晓,刘国权,宋月鹏,等.淬火钢件冷却速度、显微组织和硬度分布的计算预报[J].钢铁研究学报,2007,19(12):49-52.