| 引用本文: | 付超,王勇,李学达,韩涛.X90钢级管线钢预精焊接头的性能研究[J].材料科学与工艺,2017,25(2):85-91.DOI:10.11951/j.issn.1005-0299.20160307. |
| FU Chao,WANG Yong,LI Xueda,HAN Tao.Research on tack-final welded joint of X90 pipeline steel[J].Materials Science and Technology,2017,25(2):85-91.DOI:10.11951/j.issn.1005-0299.20160307. |
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| 摘要: |
| 为综合研究X90管线钢的焊接性，选用国内某钢厂轧制的X90管线钢卷板，利用预精焊工艺制备试验钢管4根，采用金相分析、扫描电镜 (SEM) 断口分析、夏比V型缺口冲击试验、拉伸、弯曲、硬度等试验，研究了焊接接头各个区域的组织和性能.试验结果表明：内外焊缝区组织均为针状铁素体，热影响区 (HAZ) 粗晶区晶粒粗化严重，主要组织为粒状贝氏体和贝氏体铁素体，在原奥氏体晶界和贝氏体板条内部存在块状或条状的 (马氏体-奥氏体) M-A组元；HAZ冲击功离散性较大，出现了单值较低 (45 J) 的试样，SEM断口分析呈现典型的解理断裂特征；焊接接头抗拉强度805~815 MPa，断裂位置均在HAZ；焊接接头反弯试样易在HAZ出现裂纹和脆断现象；HAZ硬度在220~250 HV之间，较母材下降30 HV左右.HAZ是X90预精焊钢管焊接接头的薄弱环节，为提高X90管线钢的焊接稳定性，应重点研究精焊内外热循环双热影响亚区的组织转变和脆化机理.
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| 关键词: 焊接 管线钢 预精焊 热影响区 马奥组元 |
| DOI：10.11951/j.issn.1005-0299.20160307 |
| 分类号:TG457.1 |
| 文献标识码:A |
| 基金项目: |
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| Research on tack-final welded joint of X90 pipeline steel |
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FU Chao1,2, WANG Yong1, LI Xueda1, HAN Tao1
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(1.China University of Petroleum, Qingdao 150001, China; 2.Shandong Shengli Steel Pipe Co., Ltd., Zibo 255082, China)
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| Abstract: |
| Four SAWH (Submerged-arc Helical Welding) pipes were manufactured by Tack-Final welding process to investigate the weldability of X90 pipeline steel. Metallographic analysis, SEM (scanning electron microscope) fractographic analysis, Charpy impact test, tensile test, bending test, and hardness test were performed. Metallographic analysis revealed that the microstructure of inside and outside welded seam was acicular ferrite, and CGHAZ (Coarse Grain Heat Affected Zone) was coarsened with blocky or elongated martensite-austenite constituent (M-A) at prior austenite grain boundaries or bainite-ferrite strip. The toughness of HAZ was discrete and low-value toughness occasionally appeared with typical cleavage fracture by SEM fractographic analysis. Tensile test confirmed that the strength of welded joint was between 805 to 815 MPa, which was fractured at HAZ. Bending test showed cracks or brittle fracture at HAZ. Analysis on hardness test indicated that hardness of HAZ was about 220~250 HV, a little bit below base metal. HAZ was weakness zone of X90 Tack-Final welding pipes. In order to improve the welding stability of X90 pipeline steel, the microstructure transformation and brittleness mechanism of HAZ sub-region should be studied further.
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| Key words: weld pipeline steel tack-final welding heat affected zone M-A |
