Vacuum Brazing of TiAl Based Alloy with 40Cr Steel

IntroductionRecently,the Ti Al based alloy has emerged asone of the structural materials with good prospectsin space,aviation,automotive and power genera-tion industries owing to their unique high- tempera-ture properties such as high specific strength andmodulus,good creep and oxidation resistance[1～3 ] .It has become well known for its excellent perfor-mance in turbine blades and engine valves for hightemperature service.These Ti Al made parts areconventionally jointed to the main body of…     

液力变矩器上盖板应力分布有限元分析及疲劳性能试验

采用轴对称有限元计算模型分析了液力变矩器上盖板及连接焊缝应力分布状态，研究结果表明，在2．4MPa工作压力下，液力变矩器上盖板的最高应力发生在上盖板弯角处的内表面上，当该表面达到屈服时，产生局部塑性变形，然后在疲劳应力作用下形成疲劳开裂。疲劳试验结果表明，裂纹都发生在上盖板弯头内表面，其开裂点和扩展方向与有限元分析得到的最大主应力位置及方向完全吻合。     

INTERLAYER MATERIALS DESIGN OF HPSN/K-500 JOINT

IntroductionBecause of the differences of crystal chemistryproperties,physical properties and surface con-ditions between ceramic and metal,the metallur-gical compatibility is very poor.It is essential tochoose suitable interlayer materials to achievethe high strengh ceramic/ metal joint.Interlayermaterials must be suitable to the propertieswhich( 1 ) would obviously reduce residual stress injoint,which may occur during cooling period be-cause of the differnet thermal expansion coeffi-cient be…     

B480GNQR钢焊接抗裂性

Ｂ４８０ＧＮＱＲ钢是我国新生产的一种耐大气腐蚀钢。本采用斜Ｙ型坡口焊接裂纹试验、插销试验、高温拉伸试验和模拟热影响区再热裂纹试验方法分别评定了Ｂ４８０ＧＮＱＲ耐修钢冷裂纹、热裂纹和再热裂纹的敏感性。     

焊接电流和保护气体对大电流MAG焊焊缝成形的影响

在相同线能量下，研究了焊接电流与不同组元保护气体(Ar、He、CO2、O2)对大电流MAG焊焊缝成形的影响。结果表明，随着电流的增大，焊缝表面由光亮平滑变为发黑起皱；焊缝截面熔池形状由指状过渡为锥形。再发展为盆形。用无He保护气体，熔池形状大电流时为蘑菇形，小电流时为指状，都不理想；大电流情况下，含He的混合气体调节范围较宽，且焊缝熔池形状比较理想，这使大电流时选用气体配比比较容易，只要保证电弧形态和熔滴过渡稳定即可，所以含He的保护气体适合于大电流的MAG焊接。     

古青铜文物钎焊修复用钎料的选择

阐述古青铜文物修复常用的Sn-Pb、Sn-Pb-Sb和Sn-Pb-Ag三种钎料和上海博物馆研制的新型钎剂匹配，进行的铺展性试验和强度试验，考察该三种钎料的钎焊性能。试验结果表明，Sn-Pb钎料的铺展性最优，Sn-Pb-Ag次之；Sn-Pb-Ag钎料的接头强度比其他两种钎料都高。综合研究表明，古青铜文物修复使用Sn-Pb-Ag钎料最佳。     

焊接线能量对12Ni19钢焊接接头中裂缝和夹杂物行为的影响

本文采用着色检查，光学显微镜观察，扫描电子显微镜观察和EDAX分析，研究了焊接线能量对TN－115焊条所焊的12Ni19钢角接 头和对接头中裂缝形貌及夹杂物形态组元的影响。结果表明，当线能量过小时，易在焊缝中形成夹渣，导致接头侧弯性能变差；若线能量过大，导致δ相转变成脆性σ相，严重时会在多层焊层间产生微裂缝。