对欧洲和我国钢轨闪光焊标准中主要指标的分析与研究(下)
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摘要
在介绍国内外钢轨闪光焊现状的基础上,从宏观形貌、微观组织和力学方面比较钢轨焊态接头和正火热处理接头性能。从焊态接头静弯试验、宏观、微观3个方面,介绍EN 14587(所有部分)《铁路应用轨道钢轨的闪光对接焊》对接头的检验要求。从正火热处理接头落锤试验、宏观、微观3个方面,介绍TB/T 1632.2—2014《钢轨焊接第2部分:闪光焊接》对接头的检验要求。通过对2项标准的分析对比认为,欧洲标准中的静弯试验检验方法和指标制定得较为合理,但试验时需要设定温度范围,才能保证试验结果可靠;我国标准中的落锤试验检验结果与试件温度关系密切,试验时达到上限温度,试验结果更容易通过;我国标准中的静弯指标偏低,应适当调整;欧洲标准要求R350HT焊接接头不允许存在马氏体,实际很难避免,建议通过限制马氏体数量来控制接头质量;我国标准中的微观组织检验方法和指标建立在热处理接头条件下,出现马氏体的概率很低,制定得较为合理。
By introducing the status quo of rail flash welding both at home and abroad,the article compares the performance of welded joint and normalized joint in terms of macroscopic macro-profile, microstructure and mechanics.Based on such three aspects as static bending test on welded joint,macroscopic view and microscopic view,it introduces the joint inspection requirements specified in EN 14587(all parts) Railway applications-Track-Flash Butt Welding of Rails. Based on such three aspects as falling weight test on normalized joint, macroscopic view and microscopic view,it introduces the joint inspection requirements specified in TB/T 1632.2—2014 Welding of Rails-Part 2:Flash Butt Welding. According to the analysis and comparison of these two standards,the static bending test method and the indicators that are developed in the European standard is relatively rational. However,reliable test results can be guaranteed only when a required temperature range is set. In the domestic standard,the falling weight test results are closely related to the temperature of the test piece. The test results can be qualified more easily when reaching the upper temperature limit during the test. The static bending indicators are relatively low in the domestic standard,which shall be adjusted properly. The European standard requires that R350HT welded joint is free of martensite,which is actually very difficult to avoid. Therefore,it is suggested to control the joint quality by limiting the quantity of martensite. The microstructure test method and indicators that are specified in the domestic standard are based on heat-treated joint,with a very low possibility for the existence of martensite,thus relatively rational.
By introducing the status quo of rail flash welding both at home and abroad,the article compares the performance of welded joint and normalized joint in terms of macroscopic macro-profile, microstructure and mechanics.Based on such three aspects as static bending test on welded joint,macroscopic view and microscopic view,it introduces the joint inspection requirements specified in EN 14587(all parts) Railway applications-Track-Flash Butt Welding of Rails. Based on such three aspects as falling weight test on normalized joint, macroscopic view and microscopic view,it introduces the joint inspection requirements specified in TB/T 1632.2—2014 Welding of Rails-Part 2:Flash Butt Welding. According to the analysis and comparison of these two standards,the static bending test method and the indicators that are developed in the European standard is relatively rational. However,reliable test results can be guaranteed only when a required temperature range is set. In the domestic standard,the falling weight test results are closely related to the temperature of the test piece. The test results can be qualified more easily when reaching the upper temperature limit during the test. The static bending indicators are relatively low in the domestic standard,which shall be adjusted properly. The European standard requires that R350HT welded joint is free of martensite,which is actually very difficult to avoid. Therefore,it is suggested to control the joint quality by limiting the quantity of martensite. The microstructure test method and indicators that are specified in the domestic standard are based on heat-treated joint,with a very low possibility for the existence of martensite,thus relatively rational.
引文
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[6]丁韦,刘艳红,黄辰奎,等.国内外铁路钢轨焊接标准接头力学性能检验方法对比分析[J].铁道技术监督,2006,34(7):4-6.
[7]张银花,周清跃,陈朝阳,等.钢轨闪光焊焊接接头轨面横向裂纹成因分析[J].中国铁道科学,2006(1):59-63.
[8]丁韦,高文会,高成钢,等.60kg/m U76NbRE钢轨闪光焊接头断裂失效分析[C].中国铁道学会,铁道科学技木新进展--铁道科学研究院五十五周年论文集.北京:中国铁道出版社,2005:816-821.
[9]潘建华.热轧合金钢轨中马氏体组织的成因及避免措施[J].特殊钢,1997,18(3):39-42.
[10]俞喆.钢轨闪光焊接头热处理工艺及性能优化研究[D].北京:中国铁道科学研究院,2012:72-73.
[2]许建学.浅谈GAAS80/580闪光焊机工艺参数的优化[J].甘肃科技,2014(10):54-55.
[3]KUCHUK-YATSENKO S I,DIDKOVSKY A V,SHVETS V I,et al.Flash-butt welding of high-strength rails of nowadays production[J].The Paton Welding Journal,2016(5):4-12.
[4]丁韦,高振坤,李力,等.钢轨闪光焊接头静弯检验标准及强度研究[J].铁道技术监督,2016,44(10):1-6.
[5]丁韦,黄辰奎,杨来顺,等.火焰正火对钢轨焊接接头金相组织及力学性能的影响[J].铁道工程学报,2002,76(2):96-98.
[6]丁韦,刘艳红,黄辰奎,等.国内外铁路钢轨焊接标准接头力学性能检验方法对比分析[J].铁道技术监督,2006,34(7):4-6.
[7]张银花,周清跃,陈朝阳,等.钢轨闪光焊焊接接头轨面横向裂纹成因分析[J].中国铁道科学,2006(1):59-63.
[8]丁韦,高文会,高成钢,等.60kg/m U76NbRE钢轨闪光焊接头断裂失效分析[C].中国铁道学会,铁道科学技木新进展--铁道科学研究院五十五周年论文集.北京:中国铁道出版社,2005:816-821.
[9]潘建华.热轧合金钢轨中马氏体组织的成因及避免措施[J].特殊钢,1997,18(3):39-42.
[10]俞喆.钢轨闪光焊接头热处理工艺及性能优化研究[D].北京:中国铁道科学研究院,2012:72-73.