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金属学报  2015, Vol. 51 Issue (4): 393-399    DOI: 10.11900/0412.1961.2014.00435
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Cr5Mo/A302异质焊接接头C扩散及其对高温蠕变寿命的影响
姜勇(), 张佐, 巩建鸣
南京工业大学机械与动力工程学院, 南京 211816
CARBON DIFFUSION AND ITS EFFECT ON HIGH TEMPERATURE CREEP LIFE OF Cr5Mo/A302 DISSIMILAR WELDED JOINT
JIANG Yong(), ZHANG Zuo, GONG Jianming
College of Mechanical and Power Engineering, Nanjing TECH University, Nanjing 211816
引用本文:

姜勇, 张佐, 巩建鸣. Cr5Mo/A302异质焊接接头C扩散及其对高温蠕变寿命的影响[J]. 金属学报, 2015, 51(4): 393-399.
Yong JIANG, Zuo ZHANG, Jianming GONG. CARBON DIFFUSION AND ITS EFFECT ON HIGH TEMPERATURE CREEP LIFE OF Cr5Mo/A302 DISSIMILAR WELDED JOINT[J]. Acta Metall Sin, 2015, 51(4): 393-399.

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摘要: 

基于时效处理实验、微观硬度测量和Fick第二定律, 对Cr5Mo/A302异质焊接接头的C扩散行为进行研究, 随后对已存在200 μm脱碳层的异质焊接接头和没有脱碳层的焊态接头进行持久实验, 研究了脱碳层在不同应力水平下对接头寿命的影响. 结果表明, 随时效时间的延长, 增、脱碳现象加剧, 增、脱碳层的宽度变化均遵循抛物线型规律, 实验测量结果与Fick第二定律拟合结果基本一致. 预先形成的脱碳层在高应力条件下, 可以成倍降低接头持久高温寿命, 导致接头发生提前断裂, 但是随着应力水平不断降低, 断裂时间不断提高, 预先形成的C扩散对接头持久寿命的影响程度不断下降, 当应力降低到接头抗拉强度的36%以下后, 其影响可以忽略. 建立了C扩散影响因子S与应力的关系, 并确定了已存在脱碳层对高温持久寿命不产生影响的临界应力值.

关键词 Cr5Mo/A302异质焊接接头C扩散C扩散影响因子S    
Abstract

Based on the consideration of economy and being easy to construct on site, Cr5Mo/A302 dissimilar welded joints are widely used in elevated temperature applications such as coal-fired power station, nuclear plant and petrochemical industry. Because of the difference in carbide forming elements on both sides of welded joint fusion line, carbon diffusion will happen in service progress and induce premature invalidation. The calculation methods of carbon diffusion and its harm to creep life of dissimilar welded joints have been investigated in the past decades. Theoretically, at a certain temperature, creep damage mechanism changes according to stress levels. However, the previous works paid little attention on the effect of carbon diffusion to creep life at different stress levels and few studies have been done focusing on relationships among carbon diffusion degree, stress level and creep life. In this work, carbon diffusion behavior of Cr5Mo/A302 dissimilar welded joint was first studied by employing aging treatment test, micro-hardness measurement and Fick's second law. Subsequently, creep tests were performed to investigate the effect of 200 mm wide decarburized zone on the joint creep life at different stress levels. The results showed that carbon diffusion in Cr5Mo/A302 dissimilar welded joints became serious with the increase of aging treatment time. The widths of carbon rich zone and decarburized zone were both consistent with the parabola distribution law and could be simulated by Fick's second law. The decarburised zone, which formed in the process of aging, reduced the creep life of the joint greatly at high stress levels. However, with the decline of testing load, its effect became much smaller. When the stress level dropped to about 36% of the yield stress, its effect was negligible. Meanwhile, the relationship of stress and carbon diffusion impact factor S was established to determine the critical value of the stress below which the decarburised zone would not affect the high-temperature creep life of the dissimilar joint.

Key wordsCr5Mo/A302 dissimilar welded joint    carbon diffusion    carbon diffusion impact factor S
    
ZTFLH:  TG457.11  
基金资助:*国家自然科学基金资助项目10172046
作者简介: null

姜 勇, 男, 1974年生, 副教授, 硕士

图 1  焊态和时效Cr5Mo/A302异质焊接接头增碳层区域的OM像
图2  焊态Cr5Mo/A302异质焊接接头熔合线附近的硬度分布
图3  时效处理后Cr5Mo/A302异质焊接接头熔合线附近的硬度分布
图4  焊态和650 ℃时效257 h后Cr5Mo/A302异质焊接接头在550 ℃, 不同应力状态下的持久寿命比较
图5  焊态和650 ℃时效257 h后Cr5Mo/A302异质焊接接头在550 ℃, 100 MPa持久实验后的断裂形貌
图 6  时效不同时间Cr5Mo/A302异质焊接接头中C浓度分布的理论计算结果
图 7  在650 ℃时效不同时间后Cr5Mo/A302异质焊接接头脱碳层和增碳层宽度实验与理论计算结果比较
图8  在650 ℃时效257 h后Cr5Mo/A302异质焊接接头在550 ℃, 80 MPa持久实验后的断裂形貌
图9  应力与C扩散影响因子S的关系曲线
[1] Lundin C D. Weld J, 1982; 61: 58
[2] Bhaduri A K,Venkadesan S. Int J Pressure Vessel Piping, 1994; 58: 251
[3] Viswanathan R,Nutting J. Advanced Heat Resistant Steel for Power Generation. London: The University Press, Cambridge, 1999: 84
[4] Jiang Y,Gong J M,Tu S T. Pressure Vessel Technol, 2004; 21(7): 13
[4] (姜 勇, 巩建鸣, 涂善东. 压力容器, 2004; 21(7): 13)
[5] Gong J M, Jiang Y, Tu S T. Acta Metall Sin (Engl Lett), 2004; 17: 560
[6] Murti K G K, Sunderesan S. Weld J, 1985; 64: 327
[7] Klueh R L, King J F. Weld J, 1980; 61: 302
[8] Lundin C D, Khan K K, Yang D. WRC Bull, 1995; 407: 1
[9] Hillert M,translated by Lai H Y,Liu G X. Alloy Diffusion and Thermodynamics. Beijing: Metallurgical Industry Press, 1984: 58
[9] (Hillert M著,赖和怡,刘国勋 译. 合金扩散和热力学. 北京: 冶金工业出版社, 1984: 58)
[10] Li Y J, Zou Z D, Zhou B. Mater Sci Technol, 2001; 17: 338
[11] Huang M L, Wang L. Metall Mater Trans, 1998; 29A: 3037
[12] Huang M L, Wang L, Ya S J, Wang F G, Yu C Z. Acta Metall Sin, 2000; 36: 902
[12] (黄明亮, 王 来, 亚生江, 王富岗, 于承志. 金属学报, 2000; 36: 902)
[13] Chen B L. Base of Metal Weldability. Beijing: China Machine Press, 1982: 106
[13] (陈伯蠡. 金属焊接性基础. 北京: 机械工业出版社, 1982: 106)
[14] Pan C, Zhang Z. Mater Charact, 1994; 33: 87
[15] Pan C, Zhang Z. Mater Charact, 1996; 36: 5
[16] Pan C X. Dissimilar Metal Welding—Microstructure Characteristic and Transformation Mechanism. Beijing: China Communications Press, 2000: 55
[16] (潘春旭. 异种金属焊接—显微结构特征及其转变机理. 北京: 人民交通出版社, 2000: 55)
[17] Li M S. Pressure Vessel Technol, 1998; 15(4): 11
[17] (李萌盛. 压力容器, 1998; 15(4): 11)
[18] Fu J S, Wang Z N. J Ningxia Univ (Nat Sci), 2004; 25(2): 317
[18] (付景山, 王治宁. 宁夏大学学报(自然科学版), 2004; 25(2): 317)
[19] Li D Y, Lou J X, Wang X Y, Zhang J, Xie T N. J Shenyang Univ Technol, 2012; 34(5): 491
[19] (李德元, 娄建新, 王晓宇, 张 晶, 谢天男. 沈阳工业大学学报, 2012; 34(5): 491)
[20] Shi C Y, Xue J R, Yu Q Z, Li Q, Yu F, Guo Y. Trans China Weld Inst, 1999; 20(4): 258
[20] (史春元, 薛继仁, 于启湛, 李 亓, 于 凤, 郭 勇. 焊接学报, 1999; 20(4): 258)
[21] Yang H J, Shi G, Zhang Y L, Lu W G, Cao S. Trans China Weld Inst, 2001; 22(4): 77
[21] (杨厚君, 石 岗, 章应霖, 吕文广, 曹 晟. 焊接学报, 2001; 22(4): 77)
[22] Lundin C D, Khan K K. WRC Bull, 1995; 405: 62
[23] Ni R C, Zhu F W. Acta Metall Sin, 1978; 14: 97
[23] (倪瑞澄, 朱逢吾. 金属学报, 1978; 14: 97)
[24] Parker J D,Parsons A W J. Int J Pressure Vessel Piping, 1995; 63: 45
[25] Parker J D. Int J Pressure Vessel Piping, 1995; 63: 55
[26] Tu S D. High Temperature Structural Integrity. Beijing: Science Press, 2003: 56
[26] (涂善东. 高温结构完整性原理. 北京: 科学出版社, 2003: 56)
[27] Dobrzanski J. J Mater Process Technol, 2004; 157: 297
[28] Dobrzanski J, Zielinski A, Sroka M. J Achive Mater Manuf Eng, 2009; 32: 142
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