Ag95CuNiLi钎料钎焊钛合金与不锈钢异种
金属的性能分析
Ò.钎焊性分析
杨静，王飞，朱金霞，刘晓荣
(中国核动力研究设计院核燃料及材料国家重点实验室，成都610041)
摘要：制备了Ag95CuNiL i钎料，参照有关的国家标准，评价了钎料的熔化特性、钎料在钛合金和不锈钢上的润湿铺展能力、钎料在钛合金和不锈钢异种金属间的填缝能力，以及钛合金/不锈钢异种金属钎缝的强度。结果表明，该钎料的液相线温度为918e，对钛合金具有较强的铺展能力，在不锈钢上的铺展性较差，钎料在钛合金和不锈钢异种金属间的漫流距离大于100mm，钛合金/不锈钢异种金属钎缝的抗拉强度达到220M Pa。采用金相显微镜、扫描电镜、X射线能谱仪和显微硬度计对钛合金/不锈钢钎缝进行了微观分析。结果表明，钎料与母材冶金结合良好，钎缝致密，在不锈钢一侧形成了三层金属间化合物组织，在钛合金一侧形成了共晶组织。
关键词:Ag95CuN iL i钎料；钎焊性；钛合金；不锈钢；钎缝组织
中图分类号:T G113文献标识码:A文章编号:0253-360X(2004)01-48-
慕斯蛋糕
04杨静
0序言
钛合金具有密度低、比强度高、导热性能好、耐腐蚀性能优良等优点，广泛地用于航空航天工业、核能工业、船舶工业、电子工业和化学精练工业。钛合金与不锈钢高质量的结合，在极端苛刻的条件下如高低温环境、腐蚀环境等表现出优良的性能，因此钛合金与不锈钢的过渡连接接头，具有现实意义和广阔的应用前景。采用钎焊、扩散焊、爆炸焊、热机械连接和形状记忆合金连接，是实现其过渡连接的有效方法，其中钎焊作为一种可靠的连接方法得到了广泛的研究。在进行钛合金与不锈钢钎焊连
郁金香的种子接中，主要使用金基和银基钎料，由于金基钎料价格较贵使其使用受到一定的限制，目前广泛使用的银基钎料制备的钎焊接头[1~5]，其腐蚀性能和高温性能并不能满足特殊环境的的要求(如核动力专用装置)。因此，根据钛合金/不锈钢过渡接头在核动力专用装置中的使用环境和可靠性要求，研制了高银含量的银基钎料Ag95CuNiLi，文中主要讨论使用该钎料在钎焊钛合金与不锈钢异种金属时的钎焊工艺性能，为该钎料的应用提供试验基础，为钛合金与不锈钢
收稿日期:2003-04-16
基金项目：江苏省船舶先进设计与制造重点实验室资助项目(200105)；核燃料及材料国家重点实验室基金资助项目
(51481050101HZ1401)异种金属钎焊接头在核动力专用装置中的使用提供技术支持。
1钎料的制备
按表1进行物料配比。配制好的物料经压制成形、高频感应冶炼等，制备所需形状的银基合金。为了解决活泼金属锂的合金均匀化，采用粉末状的银粉、铜粉和镍粉进行压制成形，在成形过程中加入锂块于混合粉末的中部，使活泼金属锂在熔炼的整个升温过程中都处于主成分的包覆中，因而有利于活泼金属锂与主成分合金均匀化。
表1钎料的名义成分(质量分数,%)
Table1Nominal compositions of brazing filler metal 元素Ag Cu Ni Li 名义成分94.8 4.00.70.5纯度99.9799.999.599.5
2试验
2.1材料
试验用母材为钛合金与不锈钢，其中不锈钢为0Cr18Ni10T i奥氏体不锈钢；钛合金是为核动力专用装置特制的T42NG钛合金，组织为A+B型(含10%的B相)，化学成分见表2。
第25卷第1期2004年2月
焊接学报
TRANSACTIONS OF THE CHINA WELDING INST ITUT ION
Vol.25No.1
February2004
表2 T 42NG 钛合金化学成分(质量分数,%)Table 2 C hemical compositions of T 42NG titanium alloy
合金牌号
化学成分
T i
Al V T42NG
基
4.0~
5.0
1.8~
2.5
2.2 试验方法
采用差热分析法(DTA)测定钎料的固相线和液相线温度；参照国家标准GB 8619-885钎缝强度试验方法6和GB 11364-895钎料铺展性和填缝性试验方法6进行钎缝强度以及钎料的铺展性和填缝性试验，其中进行填缝性试验时钛合金作为底板，不锈钢作为立板。
搭接试样的制备采用母材尺寸为18mm @15mm @2mm ，经240号水磨砂打磨，钎料和打磨后的母材用汽油清洗、超声波热水清洗、丙酮清洗，吹干后放入无水乙醇中静置2h 以上，最后吹干。使用片状钎料置于钛合金与不锈钢之间，加20g 载荷于顶板上，在真空钎焊炉中制备搭接试件。在金相显微镜下观察搭接试样横断面钎料/母材扩散层、钎缝缺陷、钎缝组织等；在扫描电镜下观察钎缝的形貌；在扫描电镜下用X 射线能谱仪分析特征微区的成分；用显微硬度计测定钎缝各微区的显微硬度。
3 结果与讨论
3.1 钎料的熔化特性
在保护气氛下对多批钎料进行了热分析。表3列出了钎料的平均固相线温度和液相线温度。
表3 钎料熔化温度(e )
Table 3 Melt temperature of brazing filler metal
固相线液相线809.7
918.3
从钎料的熔化特点来看，钎焊温度可以选择在低于T42NG 钛合金的相变温度以下(钛合金A 至B
的相变温度大约为970e )；同时钎料的熔化区间较大，这与合金相图一致，钎料较大的固相线和液相线温差，将给钎焊接头的制备带来一定的困难，容易引起熔析等现象发生。
3.2 钎料对母材的润湿、铺展性
在960e 钎焊温度下，分别在钛合金、不锈钢两种材料上对钎料进行了铺展试验，图1为同一温度下在不同母材上的钎料铺展试验结果，图2为不同温度下钎料在钛合金上的铺展试验结果(铺展试验
钎料用量都为0.2g)。从形成的铺展样品来看，钎
料对钛合金的润湿能力很强，在920~960e 范围内，随着温度的升高，铺展面积增大，润湿能力增强；钎料对不锈钢的润湿性较差[6]。
图1 钎料对两种母材的铺展(960e ,1min)Fig.1 Test result of spreadability of f iller metal over stainless steel and Ti alloy (960e ,1min)
3.3 钎料的填缝能力
在960e 温度下，按国家标准GB 8619-88对
钎料进行了填缝能力试验。试验中，分别用钛合金、不锈钢作试样的底板和立板。从试验结果来看，钎料填满了整个间隙，漫流距离大于100mm，并形成了半圆形的钎角。这是由于钎料对钛合金润湿能力很强，同时在填缝过程中,Ti 部分溶解在钎料中，增加了钎料对不锈钢的润湿性，从而使钎料流布整个间隙，并形成了半圆形的钎角。3.4 钎缝强度
表4列出了钎料的抗拉强度、钎缝的抗拉强度和剪切强度。
表4 钎料及钎缝强度
Table 4 Strength of filler m etal and brazing am
钎料抗拉强度R bf /M Pa 钎缝抗拉强度R bi /M Pa 钎缝剪切强度
欢快的
S /M Pa 175
伯的读音220
122
钎缝剪切试样的制备条件为钎焊间隙0.25mm,960e 、10min 、真空1@10
-2
Pa，不锈钢
第1期杨 静，等:Ag95CuNiLi 钎料钎焊钛合金与不锈钢异种金属的性能分析 Ò49
图2 不同温度下钎料对钛合金的铺展(1min)
Fig.2 Test results of spreadability f or f iller metal above Ti (1min)
作为套管，拉伸试样的制备条件为钎焊间隙0.20mm,960e 、10min 、真空1@10-2
Pa 。从试验结果来看，银基钎料自身的强度不高，钛合金/不锈钢钎缝的抗拉强度可达到220MPa 。对钎缝断口在扫描电镜(SEM )下观察，图3为断口的SEM 形貌，从图中可以看出，脆性断裂和韧性断裂同时存在。表5列出断口成分，可以看出在断口处具有明显的不锈钢成分特征，因此，断裂位置在钎缝区域,
并靠近不锈钢一侧。
图3 钎缝断口形貌Fig.3 Fractograph of brazed joint
表5 钎缝断口成分
钢柱Table 5 C hemical compositions of fractured surface
元素AI
T i
Cr
Fe
Ni
Cu
Ag
摩尔分数(%) 2.1039.64 1.4811.19 2.328.3234.62质量分数(%)
0.8036.84 1.09 8.83 1.92
医生简笔画7.4752.79
3.5 钎缝组织
图4是钛合金/不锈钢钎缝经蚀刻后的组织，图4a 、b 分别是在扫描电镜下观察到的钛合金-钎料界面和不锈钢-钎料界面的SEM 形貌，图4c 是
在金相显微镜下观察的钎缝组织。接头界面结合紧
密，在钎缝的扩散区、界面区和钎缝中心区没有发现微裂纹。在钛合金一侧形成共晶组织。当钎焊后冷却速度较快时，将沿钛合金界面形成薄薄一层A 型粗大针状组织，由于钎料成分进一步沿钛合金晶间扩散，形成了共晶钎缝组织的特征。在不锈钢一侧，形成了金属间化合物类型的界面区组织，扫描
电镜下可以观察到三层化合物的特征[7,8]。从钎缝中各区显微硬度的分布(图5)以及钎缝各微区成分分布(表6)可以证实在不锈钢一侧形成了金属间化合物组织。
图4 钎焊接头的组织特征
Fig.4 Microstructural characterization of brazed joint
图5 试样剖面上显微硬度分布(试验载荷10g)Fig.5 Microhardness of cross ction of brazed joints
50 焊 接 学 报第25卷
表6X射线能谱特征微区成分分析结果(摩尔分数,%)
Table6Region composition for brazed joint
微区T i-K AI-K Ag-L Cu-K Fe-K C r-K Ni-K A80.42 6.10 2.7210.11)0.460.19 B13.39 1.6024.2959.680.650.39)
C 2.920.4225.8070.160.280.39)
D11.07 1.33 3.6579.06 2.570.14 2.17 E22.330.268.0661.99 4.71 1.27 1.38 F 3.000.410.03 1.7
366.2623.06 3.24
4结论
(1)钛合金与不锈钢异种金属的钎焊, Ag95CuNiLi钎料具有较好的钎焊工艺性能。
(2)钎料与母材的界面冶金结合良好，钎缝致密，在不锈钢一侧形成了三层金属间化合物组织，在钛合金一侧形成了共晶组织。
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作者简介：杨静，男,1967年8月出生，工学硕士，副研究员。主要从事核动力异种金属连接技术研究，发表论文5篇。Email:fmkl@
[上接第47页]
4结论
根据局部法定量研究了X80、X65管线用钢焊接接头韧脆转变温度区间内的断裂行为，着重探讨了试样几何形式和匹配状态对断裂行为的影响。在焊缝金属相同的条件下，由一种接头标准三点弯曲试样的断裂韧度结果对不同匹配接头及同种接头双边裂纹拉伸试样的断裂特性进行了预测。结果表明预测结果和试验结果吻合良好，局部法能很好地描述管线钢接头韧脆转变温度区间内的断裂行为。
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Email:hji ng@
第1期杨静，等:Ag95CuNiLi钎料钎焊钛合金与不锈钢异种金属的性能分析Ò51
versity,Tianji n300072,China).p4044
Abstract:T o obtai n effective signals of droplet,w hich has become a pressi ng problem,is esntial for droplet transfer control in M IG w eld-ing.This paper has introduced the method to detect droplet t
ransfer by m eans of arc includi ng the ex peri m ent ts,testi ng pri n ciple and data processing procedure.It has been discovered that arc spectrum signal can detect and measure th e transfer procedure,the transfer modes and the transfer parameters.The arc spectrum signal enj oys excellent quality w ith hi gh signal amplitude,each transfer mode has its specific signal mode,and the pul outli ne corresponds to the development of a droplet transfer procedure.All the features of arc spectrum signal can be easily applied in transfer procedure control,transfer mode identification and stabilization and transfer parameters meas urement.
Key words:M IG welding;arc spectrum;signal feature;droplet transfer;detection
Prediction of fracture toughness for welded joints in brittle-ductile transition temperture JING Hong-yang,XU Lian-yong,HUO L-i xing,ZHANG Yu-feng(Ti anjin Uni ve rsi ty,Ti aji n300072,Chi na).p4547,51 Abstract:The fracture toughness CT OD was measured for the X80 and X65w elded joints in th e brittle-ductile transi tion temperature.T he effects of strength mis-matchi ng and specimen geometry on the fracture behavior for w elded joint w ere conducted by experiment.T he parame-ters controlling brittle fracture are gotten from the fracture toughness re-sult of standard3point bending specimen,then the fracture behavior of the tension specimen for the w elded joi nt w ith different strength m i s-matching are predicted bad on the local approach.It is found that
the predicted result is in a good agreement w ith the experiment,and the lo-cal approach gives a good description of brittle fracture even though duc-tile crack grow th prior to fi nal fracture occurs.
Key words:local approach;fracture toughness;ductile crack growth;strength mis-matching
Properties analys to Ag95CuNiLi filler metal on brazing titanium al-loy to stainles s steelÒYANG Jing,W ANG Fei,ZH U Jin-xia, L IU Xi ao-rong(T he National Key Laboratory for Nuclear Fuel&M ate-rials,Nuclear Pow er Institute of China,Chengdu610041,China).p48-51
Abstract:The Ag95CuNiLi brazing filler metal was made.Refer to concerned s tandards and tes t procedures,melting characteristi c of the filler metal,tested the spreadabili ty and clearance fillabitity for the filler m etal on brazi ng titanium alloy to stainless s teel w ere es timated,and m echanical properties of brazed joints w ere tested.Tesi ng results ind-i cated that liquidus temperature of th e filler m etal was918e,that spreadability was good on titan i um al loy and was difference on stainless steel,that slow-fl ow length was bigger than100mm,that tensile strength of brazed joints w as220M Pa.The microexamination to brazed joints examined that the bonding of the brazing filler metal and bad materi al w as all right,and three layers structure of intermetallics on the side of the stainless steel w as formed,and the eutectic structure on the side of titanium alloy was formed.Light and electr
on microscopy, S EM,micro-hardness,tensile and sh ear testing w ere ud to support the investi gation.
Key words:Ag95CuNiLi brazing filler m etal;brazabi lity;stainless steel;tianium alloy Nu merical study on influence of rupture strain on crack driving force of welded joints with damage LI J-i hong,ZHANG Jian-xun(M aterial Science and Engi neering S chool,Xi.an Jiaotong University,Xi.an 710049,China).p5256,60
Abstract:Fully coupled strain and damage elastic-plastic finite ele-ment analysi s w as carried for three-point bend specimens w ith w elded joi nt containing damage,and the influence of rupture stain E fB,that is, one of damage parameters of ba metal on crack driving force J-integral w as discusd in detail.The results show that the rupture strain of ba metal has large effects on the fracture behavior of crack in weld metal.If mechanical parameters of w eld metal are kept constant,the plasti c strai n along the ligament and the crack dri ving force J-integral increa both w ith the decrea of the rupture strain of ba metal,the increa of damage rate and the enlarge of damaged zon e subquently for all kinds of welded joint w ith different strength match i ng ratio.H ow ever,w ith the decrea of strength matching ratio(viz.the increasi ng of the strength of ba metal),or w ith the i ncrea of w eld w idth,the effect of the rupture strain of ba metal on the J-i nt慢性咽炎症状
egral is w eaken gradually, and m ay vanish entirely w hen the w eld metal parameter2H/a is more than0.6in this investigation,the value of the J-i ntegral calculated from w elded joint speci m ens is equal to that from full w eld metal specimen.
Key words:w elded joint;damage;J-integral
A Lab View-bad weld visual recognition ZHU Zhen-you,PIAO You-jie,LIN Tao,CH EN Shan-ben(School of M aterials Science and Eng,Shanghai Jiaotong U niv,Shanghai200030,China).p5760 Abstract:The pattern match and recognition for w eld image w ere realized by using the sub-VI in Labview and the combination of the traditional pattern match technology an d the edge information of the w eld.T he results prove that this m ethod can recognize th e w eld accu-rately.It provides the pre-condition and foundation for w elding robot to arching for the w eld.
Key words:Labview;w eld;pattern match;recognition
Finite element calculation of residual stress on electron beam welded BT20plates CHEN Fu-rong1,HUO L-i xing2,ZHNAG Yu-feng2, LIU Fang-jun3,CHEN Gang3(1.College of M aterial Science and Eng-i neering,Inn er M ongolia Politechnic University,H ohhot010062,Ch-i na; 2.College of M aterial Science and Engineering,Tianjin University, Tian ji n300072,China;3.Beijing Aeronautical M an
ufactaring Techndo-gy Rearch Institute,Beijing100024,China).p6164,70
Abstract:T he w elding temperature field,the distributions of resid-ual stress as w elded(AW)and electron beam local post-w eld heat treatment(EBLPWHT)of BT20plates have been successfully simulated w ith a th ree-di mensional fi nite-elem ent model(FEM).In the w eld cen-ter,the maximum magnitude of residual tensile s tress of BT20thi n plates of titani um alloy is equal to60%70%of its yield s trength R s.The residual tensile stress in w eld center can be even decread after EBLP-WHT and the longitudinal tensile stress are decread about50%com-pared to the joints in AW conditions.The numeri cal calculating results of residual s tress by using FEM are basically in agreement w ith the ex-perimental resul ts.Combined with numerical calculating results,the ef-fects of electron beam w eling on the distribution of w elding residual stress in thi n plates of BT20has been anal yzed in detail.
2004,Vol.25,No.1TRANSACTIONS OF THE CHINA WELDING INST ITUT ION5
