D0I:10.13374/i.issnl00113.2009.s1.025 第31卷增刊1 北京科技大学学报 Vol.31 Suppl.1 2009年12月 Journal of University of Science and Technology Beijing Dee.2009 EAF LF(VD)VT工艺生产曲拐用钢S34nV的洁 净度研究 刘剑辉)朱荣)林腾昌)闵兴海) 曲素君)庞宗旭)白 静 1)北京科技大学冶金与生态工程学院，北京1000832)鞍钢重机公司铸钢厂，鞍山114021 摘要针对EAF-LF(VD)一VC工艺生产的大型船用s34MnV曲拐探伤不合的问题，分别在电炉还原期，LF-VD精炼期、 浇注和锻造后钢锭取样对钢中夹杂物进行了研究·结果表明，精炼期间大于15m的夹杂物比例波动在1.65%~10.34%之 间：钢锭横截面上凝固前沿的柱状晶截获夹杂物的几率不同，帽口中心部位大型夹杂物含量少于边部试样夹杂物含量为5.81 mg/10kg钢锭尾部中心部位夹杂物含量高于边部试样夹杂物含量为25.9mg/10kg:锻造钢锭中夹杂物富集严重，其中尾部 DS类夹杂达到了4级以上·钢锭锻造后尾部含有大型夹杂物聚集部分不能完全切除是目前导致产品探伤不合的一个主要原 因 关键词洁净度；s34MV:曲拐；电弧炉：真空精炼；大型钢锭 Study on the cleanliness of crank steel S34MnV produced by the EAF-LF(VD)- VT LIU Jian-hui),ZHU Rong,LIN Teng"chang),MIN Xing-hai).QU Sujun2).PANG Zongxu2).BAI Jing?) 1)Metallurgical and Ecological Engineering School.University and Science Technology Beijing.Beijing 100083.China 2)Steel Casting Foundry.Angang Heavy Machine Co.,Ltd.Anshan 114021.China ABSTRACT The experimental samples were the marine crank steel S34MnV produced by the EAF-LF(VD)-VC production pro- cess,including the electric period,LF-VD refining period,casting period,and forging ingots from a heavy machinery factory in north China to solve the difficulty of being rejected by ultrasonic flaw detection for crank shaft.These samples were analyzed by the methods of metallographic observation,energy spectrum,and the electrolysis.The obtained results indicated that there was a large number of inclusions during the refining stage,and the proportion of inclusions with the size bigger than 15/m accounting to total in- dusions were within 1.65%-10.34%after VD process.Furthermore.the probability of inclusions captured by columnar crystal in the steel ingot cross"section was found changed obviously in different locations of ingot cap.The content of large inclusions in the cen- ter of the beginning of the ingot cap was 5.81mg/10kg,with increasing the distance from the center to the edge.whereas this value decreased to only 25.9mg/10kg in the rear center of ingot cap,with decreasing the distance form the center to the edge.In addition. large numbers of inclusions was found to exist in the forging ingot with the biggest inclusion of a 140m DS category,which were dif- ficult to be cut off completely and would be the main reason of being rejected by ultrasonic flaw detection for crank shaft. KEY WORDS cleanliness:S34MnV:crank shaft:EAF:vacuum refining:heavy ingot 随着世界船舶工业的迅速发展，70年代以来船 和震动附加力矩，因此要求曲拐有较高的刚度、抗冲 用锻件规格越来越大，技术要求越来越高，生产难度 击性能、，扭曲强度和疲劳强度，这些对曲拐用钢的洁 也越来越大，特别是近几年我国造船业也迅猛发净度及锻造加工提出了更高的要求，因为尺寸大， 展山.曲拐是大型船舶低速大功率发动机的核心， 曲拐均采用自由弯曲锻造的方法制造).本文对锻 它与发动机和螺旋桨联结传递动力，在高温工作环 造后曲拐探伤不合的问题，分别在冶炼过程中和钢 境下承受周期性变化的弯曲和扭转力矩、惯性力矩 锭锻造后进行了取样分析，研究了不同工序夹杂物 收稿日期：2006-08-01 作者简介：刘剑辉(1973一)，男，博士研究生，E-mail:lgliujianhui(@hotmail.comEAF－LF（VD）－VT 工艺生产曲拐用钢 S34MnV 的洁 净度研究 刘剑辉1） 朱 荣1） 林腾昌1） 闵兴海2） 曲素君2） 庞宗旭2） 白 静2） 1） 北京科技大学冶金与生态工程学院‚北京100083 2） 鞍钢重机公司铸钢厂‚鞍山114021 摘 要 针对 EAF－LF（VD）－VC 工艺生产的大型船用 S34MnV 曲拐探伤不合的问题‚分别在电炉还原期、LF－VD 精炼期、 浇注和锻造后钢锭取样对钢中夹杂物进行了研究．结果表明‚精炼期间大于15μm 的夹杂物比例波动在1∙65％～10∙34％之 间；钢锭横截面上凝固前沿的柱状晶截获夹杂物的几率不同‚帽口中心部位大型夹杂物含量少于边部试样夹杂物含量为5∙81 mg／10kg；钢锭尾部中心部位夹杂物含量高于边部试样夹杂物含量为25∙9mg／10kg；锻造钢锭中夹杂物富集严重‚其中尾部 DS 类夹杂达到了4级以上．钢锭锻造后尾部含有大型夹杂物聚集部分不能完全切除是目前导致产品探伤不合的一个主要原 因． 关键词 洁净度；S34MnV；曲拐；电弧炉；真空精炼；大型钢锭 Study on the cleanliness of crank steel S34MnV produced by the EAF－LF（VD）－ VT LIU Jian-hui 1）‚ZHU Rong 1）‚LIN Teng-chang 1）‚MIN Xing-hai 2）‚QU Su-jun 2）‚PA NG Zong-xu 2）‚BAI Jing 2） 1） Metallurgical and Ecological Engineering School‚University and Science Technology Beijing‚Beijing100083‚China 2） Steel Casting Foundry‚Angang Heavy Machine Co．‚Ltd‚Anshan114021‚China ABSTRACT T he experimental samples were the marine crank steel S34MnV produced by the EAF－LF（VD）－VC production pro￾cess‚including the electric period‚LF－VD refining period‚casting period‚and forging ingots from a heavy machinery factory in north China to solve the difficulty of being rejected by ultrasonic flaw detection for crank shaft．T hese samples were analyzed by the methods of metallographic observation‚energy spectrum‚and the electrolysis．T he obtained results indicated that there was a large number of inclusions during the refining stage‚and the proportion of inclusions with the size bigger than15μm accounting to total in￾clusions were within1∙65％－10∙34％ after VD process．Furthermore‚the probability of inclusions captured by columnar crystal in the steel ingot cross-section was found changed obviously in different locations of ingot cap．T he content of large inclusions in the cen￾ter of the beginning of the ingot cap was5∙81mg／10kg‚with increasing the distance from the center to the edge‚whereas this value decreased to only25∙9mg／10kg in the rear center of ingot cap‚with decreasing the distance form the center to the edge．In addition‚ large numbers of inclusions was found to exist in the forging ingot with the biggest inclusion of a140μm DS category‚which were dif￾ficult to be cut off completely and would be the main reason of being rejected by ultrasonic flaw detection for crank shaft． KEY WORDS cleanliness；S34MnV；crank shaft；EAF；vacuum refining；heavy ingot 收稿日期：2006-08-01 作者简介：刘剑辉（1973－）‚男‚博士研究生‚E-mail：lgliujianhui＠hotmail．com 随着世界船舶工业的迅速发展‚70年代以来船 用锻件规格越来越大‚技术要求越来越高‚生产难度 也越来越大‚特别是近几年我国造船业也迅猛发 展［1］．曲拐是大型船舶低速大功率发动机的核心‚ 它与发动机和螺旋桨联结传递动力‚在高温工作环 境下承受周期性变化的弯曲和扭转力矩、惯性力矩 和震动附加力矩‚因此要求曲拐有较高的刚度、抗冲 击性能、扭曲强度和疲劳强度‚这些对曲拐用钢的洁 净度及锻造加工提出了更高的要求．因为尺寸大‚ 曲拐均采用自由弯曲锻造的方法制造［2］．本文对锻 造后曲拐探伤不合的问题‚分别在冶炼过程中和钢 锭锻造后进行了取样分析‚研究了不同工序夹杂物 第31卷 增刊1 2009年 12月 北 京 科 技 大 学 学 报 Journal of University of Science and Technology Beijing Vol．31Suppl．1 Dec．2009 DOI:10．13374／j．issn1001－053x．2009．s1．025