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1、江克斌第29卷第1期焊 接 学 报Vol. 29 No.l2 0 0 8 年 1 月 TRANSACTIONS OF THE CHINA WILDING INSTITUTION2008T江克斌，肖叶桃，郭永涛(解放军理工大学工程兵工程学院南京210007):为了掌握钢结构中焊接残余应力的具体分布状态采用基干逆磁致伸缩效应 原理的无损检測方法利用磁測应力仪对T型焊接试件焊縫附近不同戻深处的焊接残 余应力进行了实际測量得到了距焊件表面1、15和2 mm三个不同层深的焊接残余应 力分布规律.并和基于有限元法的数值模拟计算结果进行了对比分析。结果表明焊縫 附近区域残余应力较大随看厦深的增加横向和纵向残
2、余应力均由压应力逐渐过渡为 拉应力而纵向残余应力在远离焊縫中心的区域内则改由拉应力过渡为压应力。:钢结构：焊接残余应力；无损测重；黴測法；逆磁致伸缩效应:TCHO4: A: 0253 - 360X(2008)01 - 0053 041994-2010 China Academic Journal Electronic Publishing House. All rights reserved, 1994-2010 China Academic Journal Electronic Publishing House. All rights reserved, 0序 言焊接是钢结构连接的一种可靠而
3、有效的方法, 钢结构在焊接过程中产生了极不均匀的温度场导 致受约束的热应变和塑性应变，从而产生了残余应 力。焊接残余应力对焊接结构性能影响非常突出， 依残余应力的大小和分布的不同它对焊接结构的 静载强度、疲劳破坏、应力腐蚀、刚性和稳定性造成 不同程度的影响因此测定并掌握焊接残余应力在 焊接结构中的分布规律十分必要。残余应力检測技 术的研究始于20世纪30年代.发展至今已形成了 几十种测量方法。这些測量方法概括起来可大致分 为两类:机械测量方法和物理测量方法或者称之为 有损测量法和无损测量法l，2,o较为常用的机械测 量方法有：切条法、小孔释放法、套孔法、盲孔法； 无损测量法主要包括：X射线衍射
4、法、电阻应变片 法、光测法、超声波法冲子衍射法和磁测法(2。 机械测量方法可靠性高、测量准确度好但它是以被 测构件或多或少地受到不同程度的破坏为代价的. 因此在实际应用上受到一定程度的限制。作者采用 基于逆磁致伸缩效应原理的无损检測方法.利用磁 测应力仪对T型焊接试件焊缝附近不同层深处的焊 接残余应力进行了实际測量。T型焊接是一种在船 舶、桥梁等领域应用较广泛的焊接形式，测定其焊接 残余应力的大小和分布对优化焊接结构和焊接工 艺设计具有重要意义。:2007 - 04-191残余应力的测量原理磁测法是利用铁磁性材料的铁磁特性对材料应 力变化或显微组织敏感这一物理特性来测定应力的° 磁致
5、伸缩是一切铁磁性物质所具有的特性所谓磁致 伸缩效应是指铁磁性材料受磁场作用时它的尺寸 大小、形状会发生变化的效应:或者当铁磁物体在原 有恒定磁场作用下.同时受外力作用发生形变瞬间会 引起内部磁场发生变化的效应。反过来铁磁材料在 外力作用下发生变形其磁化强度将随之变化的现象 叫做逆磁致伸缩效应。在这种情况下材料产生各向 异性因此应力或应变状态的变化将会引起铁磁材料 的磁导率或磁阻的变化。在向磁各向异性传感器提 供恒定的磁动势的条件下磁路中磁阻的变化将引起 磁通的变化传感器上的检测线圈感应出的感生电动 势的变化将反应这种变化。从而可将非电量的应力 应变转化成可以测量的电量(如电压)达到应力监测 的
6、目的，这就是利用逆磁致伸缩效应测量应力的基本 原理。其变化过程如式(1):F -A A Rm F (1 丿 式中为应力变化量厶 为铁磁材料磁导率变化 量厶心为磁路中磁阻的变化量. 为传感器输出 电压的变化量5。2试验方法试验采用Q235钢T型焊接试件.焊接采用00： 气体保护焊环境温度为26 °C.具体的焊接工艺参 数见表1。两条焊缝的顺序用1、2标示方向用1994-2010 China Academic Journal Electronic Publishing House. All rights reserved, 1994-2010 China Academic Journal
7、 Electronic Publishing House. All rights reserved, 第1期江克斌等:T型焊接试件焊接残余应力分布的测定#标示.其构造型式和具体尺寸如图1所示。测应力仪” 该仪器采用了铁磁材料逆磁致伸缩效应测量设备是国内最新研制生产的-98磁的原理。Table 1 Welding parameters焊丝惮号焊丝直径 啊nim焊接速度/ (nm s* l)电弧电压U/V焊接电流/A气体流量 q! (L nin l)CHW 50CX)SM1.20.00528200201994-2010 China Academic Journal Electronic Publi
8、shing House. All rights reserved, 第1期江克斌等:T型焊接试件焊接残余应力分布的测定#1994-2010 China Academic Journal Electronic Publishing House. All rights reserved, 第1期江克斌等:T型焊接试件焊接残余应力分布的测定55(a)MMU件示意图应力分量就可用切应力差法求得；i丿 u12655265(b)MttU件尺寸图(mm)(R、J p =( x) p ( R Z?2丿 />COS2 p (6)(e R7“ r(xy) p =2 Sin2 P仃丿式中:为边界点的已知应力值
9、.对自由边界凡0 =0 0如改变激磁电流频率/可改变趋肤深度 来改 变測量深度即=503点 式中.为电阻率3 -m);为相对导磁率./为频率 (Hz)。1Eg. 1 Test specimen在试件翼板上画好网格线.取X轴垂直焊縫方 向轴平行焊缝方向y为网格间距通常 a A y不大于20 mm.且 x = y,这里都取10mm, 測点即为每个网格交叉点(如图2)。将计算机、磁測 应力仪、探头连接好(如图3丿后即可开始测量.测量 时两个探头一个放在补偿试件上并保持位置不挪 动另一个探头放在待测试件上c此应力仪测量焊接 残余应力是采用切应力差法.逐点推求应力大小与 分布规律的测量时需測量每个交叉点
10、上三个方向 (0、45、90丿的电流值c測量的电流差和两个方向主 应力差近似存在线形关系.其表达式为(b h) =(& Ri)(2)式中:R为最大主应力(MPii) ; R,为最小主应力 (MPa) : h为最大主应力方向电流输出值(mA): h为 最小主应力方向电流输出值(mA)；为灵敏系数 (由标定试验确定.mA/MPa)。主应力方向未知时，可用式(3八式(4丿确定主 应力方向角和主应力差即=fl ( /<» Ak Am 丿(3丿(心 R2)= f2( Io. /<X>.丿(4)式中：为最大主应力方向与X轴的夹角，/().厶5顶 为0 .45 .9()三
11、个方向的测量电流值(mA)。已知各点的主应力差和主方向角，任一点尸的TOo23vsx 3B 195 1K5190205rifisi210 mm(mm)Fig. 2 Arrangement of measuring points on wing panel when mesh spacing is 10 mm3Eg. 3 Schematic diagram of connecting equipment whenmeasuring residual stresses1994-2010 China Academic Journal Electronic Publishing House. All
12、rights reserved, 第1期江克斌等:T型焊接试件焊接残余应力分布的测定57试件在层深1 ,1.5.2 mm上的横向残余应力和 纵向残余应力分布见图4 其中图4n .b显示了图2£厦2sa«-R020 40 60 80 100 120 140 160 180 200 审焊趾即寓/mmdw/H 燈20 40 60 80 100 120140160180200 220 晚弊:距贏Umm(b)第2条焊強不同层深的横向残余应力R,(fi 160120()第1条焊缝不同层深的横向残余应力K,tf( 160-120S-R崔-120-160160120dx/M 套试20 40
13、 60 80 100 120140160180200 220 审焊M距真Umm(c)豹1条弊缝不同凰ft!的纵向歿余应力心值距焊趾距离Umm(d)第2条焊缝不同层深的纵向歿余应力 “-12()4Fig. 4 Residual stresses distribution in layers of ditterent depths in wing panel3试验结果及分析中y = 45 mm处横向残余应力的分布规律:图4c, d显示了该处纵向残余应力v的分布规律。从图4可以看出焊接残余应力是不均匀的，靠 近焊缝处存在较大的残余应力值随着不断的远离 焊缝区域残余应力逐渐减小，在焊缝两侧一定距离 处
14、应力值较小在零值附近变化。图4中层深 2 mm处残余应力分布与文献纠采用有限元模拟技 术对T型焊接试件残余应力分布的计算结果和文献 9采用X射线衍射法的实测结果的分布趋势大致 相同.但文献8没有考虑不同层深的残余应力分 布文献【9采用的X射线法也只能测得构件表层 的残余应力。此次试验测得了三个层深的残余应力分布，试 验结果进一步验证了焊接残余应力呈现复杂的空间 分布状态。残余应力在不同层深分布规律是不同 的。层深1 mm时.横向、纵向残余应力在焊缝附近 均为压应力；层深1.5 mm时，横向、纵向残余应力均 在零值附近变化:层深2 mm时横向、纵向残余应力 在焊缝附近均为拉应力。其中层深2 mm
15、处的纵向 残余应力在焊縫中心线附近为最大拉应力在距离 焊縫中心约40 mm时降至最大压应力.之后随着离 焊縫距离的进一步増大残余应力逐渐减小为零 层深1 mm处的纵向残余应力的变化趋势则与之相 反。而层深1、2 mm的横向残余应力则没有出现在 焊缝附近拉压变化的情况。不同层深的残余应力 在焊缝1和焊缝2侧的数值大小不同.说明在焊缝2 的施焊过程中使得焊缝1附近的残余应力分布发生 了变化但两条焊缝的横向、纵向残余应力在远离焊 缝方向上的变化趋势却大致相同。从图4可看出心皿说明此焊接试件易 产生y向裂纹。为进一步研究焊接结构不同层深的残余应力分 布通过大型通用软件ANSM的热一应力耦合功 能建立三
16、维有限元模型:采用间接法利用“单元生 死”技术和APDL语言对T型焊接试件的温度场和 应力场进行数值模拟"叫。考虑到计算容量和效率, 数值模拟中采用了小尺寸模型。焊接残余应力的 ANSM计算结果和实测结果的对比情况如图5所 示。从图中可以看出分布趋势大致一样数值的差 异可能是由于材料高温特性参数的取值所造成的, 另外建模过程中模別尺度的选取以及加栽过程中高 斯分布热源的简化等也会造成一定的计算误差。从 图5的对比分析可以看出在焊縫附近区域内实测 结果能够较好地反映不同层深处焊接残余应力的分 布规律。1994-2010 China Academic Journal Electronic
17、 Publishing House. All rights reserved, 第1期江克斌等:T型焊接试件焊接残余应力分布的测定#o 20 -40 -601520253035审焊趾审离 mmUmm(c)灼冬1魁层深1mm上纵向残余应力&对比图120100S0604020IS 202530 3S阪炸It审离Umm(b)焊缝1处层深2mm上横向残余应力凤对比图150100500-50-100-1501520253035距弊趾即戾mm(d)焊建】处泾秣2mm上纵向残余应力心对比图1994-2010 China Academic Journal Electronic Publishing H
18、ouse. All rights reserved, 第1期江克斌等:T型焊接试件焊接残余应力分布的测定#1994-2010 China Academic Journal Electronic Publishing House. All rights reserved, 第1期江克斌等:T型焊接试件焊接残余应力分布的测定#Fig. 5 Comparison between test re stilt s and numerical simulation results1994-2010 China Academic Journal Electronic Publishing House. Al
19、l rights reserved, 第1期江克斌等:T型焊接试件焊接残余应力分布的测定#1994-2010 China Academic Journal Electronic Publishing House. All rights reserved, 第1期江克斌等:T型焊接试件焊接残余应力分布的测定594结 论(1) 通过对T型焊接试件残余应力分布的測 量基于逆磁致伸缩效应的磁测法操作方便、快捷、 实用.并且可以测得铁磁材料一定深度内不同层深 的残余应力分布。(2) 焊接残余应力測量结果表明：焊缝区及附 近存在较大的焊接残余应力.应力最大值接近材料 屈服强度。不同层深残余应力变化规律不同
20、对于 横向残余应力是由压应力逐步过渡到拉应力：对于 纵向残余应力在靠近焊縫的区域上也是由压应力 逐步过渡到拉应力随着远离焊縫的区域则是由拉 应力逐步过渡到压应力。(3) 由于铁磁材料在各类工程结构中大量应 用加上磁测法測量速度快，探测深度大，无辐射危 险等优点.磁测法有很大的应用潜力。12徐 虹腾宏春崔 波等 残余应力非破坏性測量技术 的发展现状简介IJI.理化检验物理分册.2003.39(11): 595 - 598.131游敏郑小玲连接结构分析IM武汉:华中科技大学出 版社.2004.14张尢栓何家文.材料中殘余应力的X射线衍射分析和应用 IMI-西安西安交通人学出版社.1999.15李生
21、田刘志远.焊接结构现代无损检測技术M.北京:机 械工业出版社.2000.16王昭林.铁磁材料应力的破弹性检測方法IJ1.煤矿机械. 1998. 19(1) : 36 37.17文西芹.刘成文基于逆磁致伸缩效应的残余应力检滴方法 UJ.传感器技术.2002.21(3):42 - 44.8 Teng TL . Fung C P. Chang P H. n al. Analysis cf reddual stresses and distortions in T-joint Gild welds |J . Intemabonal Journal of hvssurc Ves®ls and
22、Piping . 2001.78 : 523 - 53&9余昌運焊接结构的残余应力研究D.武汉：武汉理工大 学.2006.1101郭永溥 基于ANSM和磁測应力技术对钢结构焊接残余应力 的研究【D.南京:解放军理工大学2007.1994-2010 China Academic Journal Electronic Publishing House. All rights reserved, 第1期江克斌等:T型焊接试件焊接残余应力分布的测定#1994-2010 China Academic Journal Electronic Publishing House. All rights
23、reserved, 第1期江克斌等:T型焊接试件焊接残余应力分布的测定#11罗建橐无损残余应力测量技术及其新技术【JI力学与实W .2003.25(4): 7- II.:江克城男957年出生博士 教授.博士生导师.主 要从事移动柝梁结构设计理论与方法的科研和敎学工作.发表论文 40余篇出版专者=5部Email : kbiiang dna.oom1994-2010 China Academic Journal Electronic Publishing House. All rights reserved, 2008 .Vol. 29 .No. 1TCANSACTIONS OF THE CHIN
24、A WELDING INSTTIUTON111nautics Nanjing 210016 . China) p35 39Abstract: Visor plastic fiiiite clement method was used to analyze the reliability on »ldered joints of QFP devices with tliree kinds of different substrate materials. The results indicate that the maximum stress of soldered joint con
25、centrates on the sluup corner of interior part of lhe joint wilh FR-4 substrate and the maximum stress focuses on the sharp comer of exterior part of the joint with LTOC substrate and lhe largest stress concentrated area is at lhe sliaip cor ner between the s)ldercd joint and lead wth PTFE substrate
26、 G)nr paring the residual stress of soldered joints with the three substrate materials the value of residual stress in the joint with FR-4 substrate is the least. and the value is middle in the soldered joint wilh PTFE substrate. and the value is the largest in the snldered joint wilh LTOC substrate
27、 The analysis results of Sn37Pb »ldered joints are in accord uith those of Sn3. 8Ag0 7Cu soldered joint. At the same time, the optimizing simulations on substrate tWcknesses are made and lhe results show that the value of residual stress is the largest in lhe soldered joint when lhe thickness i
28、s 0. 8 nun.Key vwrds : finite element met Ind: substrate materials; maximum stress: substrate thicknessHTects tf iianoscale powder on emting deposited by axhl jias- nra spying Tit/ AhO composite powdersCHENGHandl, LI Zliuoxin1 , SHI Vkwd , LI Qilian2 , LI Shuqing2 (1. Cbllcge of Material Science and
29、 Engineering Beijing Universily of Technology Beijing 100()22 China : 2 Beijing Aeronautical Manufacturing leclui)k)gy, Research Instil ute , Beijing 100024. China). p40 44Abstract : TIB：/ AI2O3 conposite coatings uere deposhed by axial plasma graying (Mctlch Axiab 111) : one of feedstock powders wa
30、s conventional niemmeter powder derived fiom self-piopagating high tenperature synthesis piocess . and lhe other was fabricated by spray drying TIB” Ah® conposite powder doped with 10 % mass fraction nawsize AI2O3 powder. Miciostructure and wear resistance of type coatings re oonpared and eft&#
31、39;ects of nano scale powder on lhe coatings were investigated Scanning election niiciusoope and X-ray diffraction analysis were used to analyze the jpra)vd coatings. and disc abrasive ear apparatus was enployed to test u«ar resistance oi the coatings. Results sluw tluit density and wear resist
32、ance of sprayed coating fiom 印ray drying powder are better than (hal fiom conxntional pouder TiQ content is also less than that in the coa ing fiom 8nvenbonal powder and superii&al Rockwell Hardnesses of tw coatings are about the sameKey w>rds : titamum di boride alunina : nanoscale powder: e
33、ixial plasma jpray: niciustructure : wear resistanceMechanism (t wkl penetration increased by SK> in AC A- TIG wldhig for aluiiiiiuin alloy HJANG bng FAN Ding ( State ©y LabonUoiy of New Noir Rirrous Metal Materials , Lanzhou University of Technology Lanzhou 730050 China) p45 49Abstract : lh
34、e weld penetration increased by SO： is the n»st obviously when some singje-conponent fluxes are used as surface ac- livating ilux in AC Ar TIG (alternating cunent activating-tungsten inert-gas) welding of aluminum alloy, lhe mechanism of Si(> increasing weld penetration of AC A-TIGuelding wa
35、s studied. SO： has little effect on ueld appearance d electron beam welding with positive ddbeus A series of DCSP A-TIGuvlding experiments vwre carried out to investigate the effects cf SCh on xwlding arc. k is found tha: SO> can constrict arc polarity area , broaden arc column and impiove arc vo
36、ltage AC Ar TIG u«elding with helium sliielding gas uus carried out. 11 is found lhal S(> constricts evaporation area weakens evaporation of activating flux or base melal and depresses udd pool sur face. During lhe welding process , SO： coating is always on the weld pool surface. Only there
37、is very iianuw gap on the central region of dq)ressed udd pool. Vapor concentrates in the ioucr middle part of arc. lhe results indicate that arc polarity area constriction and input heat increase are the main mechanism to increase ueld penetration by SO： in AC A-TIG welding for aluiiinuin alloy.Key
38、 w>rds : SO；: al uni num alloy: alternating current activating-tungsten inert-gas uelding; weld penetrationdlcuhting method rdbibiity on anti fatigue fracture tf wldLIN Qjoxiang YEJinbao QRJ Changjun (School of Mechanical Engineering. University of South China Hengyang 421001 , Hu- nan . China) p
39、50 - 52Abstract: Fatigue fracture often happens in welded joint wilh liigh strength in engineering practice lhe reliability of weld anti fatigue in safe sloiild be estimated. Accordii唱 to fatigue fracture theo- ryof metal material and dril't principle in reliability technology the method to calc
40、alate the reliability under the failure rate uith a certain cycle numbers or under the cycle numbers uitlx)ut failure was discussed by using crack-length bd'ore wld fatigue fracture as outpul parameter A praitical exanple was used to design the reliability of anti fatigue failure strengh of weld
41、 under the condition of the giwn cyvle numbers and reliability.Key w>rds : voided joint: fatigue fracture; reliabilityDetermination tf adding residml stress distribution in Fshape vwldcd specimen JIANG ©bin XIAO fetao , GUO Y)nglao (Engineering Institute of Engineering Chips ILA University o
42、f Science and Technology . Nanjing 210007 .China) p53 - 56Abstract : In order to kiw* the distribution of welding residual stresses in wdded structures the nondestructive test met Ind based on counter magnetostrictive eftect and the magnetic measurer were used to measure lhe welding residual stresse
43、s in different depths of the Tshape wvlding 尹ecimcn lhe residual stress distribution in 3 layers (Imni 1 5 mm and 2 mm from the vwlding surface) ot the vwldn叱nt was ob(mned and oonpared wilh those fiom lhe numeral simulation by lhe fimte element mclhod. The results stow lhal the transverse and longi
44、tudinal residual stresses in the area near the wdd are conparatiwly large and vary fiom compression to tension as the deplh increasing while the longitudinal residual stresses vary from tension to oonpression in the area apart ffum lhe weld.Key wrds : steel structure; welding residual stress: nonde-
45、 structive measuring: magnetic survey method: counter magneto st ric- ti« effectDiffusion elding tf AhLi alloys 1420 with pulsed current PENG 6ng, FU Zhengji , WANG Weiniin. WANG Hao , WANG Yuchcng . ZHANG Jin>ong ZHANG Qingjic (Slate Key Laboratory for Advanced 7echix)log)r of Materials Syn
46、thesis and ftocessing. Wuhan Universily of lechnofogy , Wuhan 430070, Qiina) p57 - 60Abstract:Pulsed current heating icchmlogy was used toueld the 1420 AHLi alloy Sanpies welded wilh different conditions uere conpared The best tensile strength of joims is 75 % of the base metal The influence of nicrostructurc on piopcrtics of joints uus analyzed The welding process was analyzed by SEM images and nicrograph pic