Mechanical strength analysis of SMT solder joints by finite element method

ＭｅｃｈａｎｉｃａｌｓｔｒｅｎｇｔｈａｎａｌｙｓｉｓｏｆＳＭＴｓｏｌｄｅｒｊｏｉｎｔｓｂｙｆｉｎｉｔｅｅｌｅｍｅｎｔｍｅｔｈｏｄ￥ＷＡＮＧＣｈｕｎｑｉｎｇ；ＷＡＮＧＲｕｉｊｕｎ；ＳＡＮＧＹａｎａｎｄＱＩＡＮＹｉｙｕ（ＷｅｌｄｉｎｇＤｅｐａｒｔｍｅｎｔ...     

Thermal behavior of B_4 Cparticles under plasma arc powder surfacing condition

ＴｈｅｒｍａｌｂｅｈａｖｉｏｒｏｆＢ_４Ｃｐａｒｔｉｃｌｅｓｕｎｄｅｒｐｌａｓｍａａｒｃｐｏｗｄｅｒｓｕｒｆａｃｉｎｇｃｏｎｄｉｔｉｏｎ￥ＷＡＮＧＸｉｂａｏ；ＺＨＡＮＧＷｅｎｙｕｅ；ＬＵＴｏｎｇｌｉａｎｄＰＥＮＧＪｉｅ（ＨｅｂｅｉＵｎｉｖｅｒｓｉｔｙ...     

Low stress no distortion welding for aerospace shell structures

ＬｏｗｓｔｒｅｓｓｎｏｄｉｓｔｏｒｔｉｏｎｗｅｌｄｉｎｇｆｏｒａｅｒｏｓｐａｃｅｓｈｅｌｌｓｔｒｕｃｔｕｒｅｓＧＵＡＮＱｉａｏ；ＧＵＯＤｅｌｕｎａｎｄＺＨＡＮＧＣｈｏｎｇｘｉａｎ（ＢｅｉｊｉｎｇＡｅｒｏｎａｕｔｉｃａｌＭａｎｕｆａｃｔｕｒｉｎｇＴｅｃ...     

HYDROGEN-VACANCY INTERACTION IN IRON

ＨＹＤＲＯＧＥＮ－ＶＡＣＡＮＣＹＩＮＴＥＲＡＣＴＩＯＮＩＮＩＲＯＮ￥ＷＡＮＧＸｉａｏｇａｎｇ（ＨｕｎａｎＮｏｒｍａｌＵｎｉｖｅｒｓｉｔｙ,Ｃｈａｎｇｓｈａ．ＣｈｉｎａＭａｎｕｓｃｒｉｐｔｒｅｃｅｉｖｅｄ３Ｊｕｎｅ１９９４）Ａｂｓｔｒａｃｔ：Ｔｈｅｄｉ...     

二OOO温哥华国际金刚石大会论文名称索引

ＡＥＲＯＳＰＡＣＥ…航空领域ＴｈｅＦｕｔｕｒｅｏｆＵｌｔｒａｈａｒｄＭａｃｈｉｎｉｎｇｉｎｔｈｅＡｅｒｏｓｐａｃｅＩｎｄｕｓｔｒｙ超硬加工在航空工业中的应用展望ＣＢＮＧｒｉｎｄｉｎｇｏｆＮｉｃｋｅｌＡｌｌｏｙｓｉｎｔｈｅＡｅｒｏｓｐａｃｅＩｎｄｕｓｔｒｙＣＢＮ磨削航空镍基合金ＰｏｔｅｎｔｉａｌＧｅｎｅｒａｔｉｏｎｏｆＭｅｔａｌＶａｐｏｒｓＤｕｒｉｎｇＤｒｙＭａｃｈｉｎｉｎｇ干切削时金属粉尘的产生ＡｐｐｌｉｃａｔｉｏｎａｎｄＰｅｒｆｏｒｍａｎｃｅｏｆＣＢＮＷｈｅｅｌｓｆｏｒＰｒｅｃｉｓｉｏｎＧｒｉ…     

OPTIMIZATION AND METHOD OF DRAWING CONTROL IN BLOCK CAVING AT TONGKUANGYU MINE

ＯＰＴＩＭＩＺＡＴＩＯＮＡＮＤＭＥＴＨＯＤＯＦＤＲＡＷＩＮＧＣＯＮＴＲＯＬＩＮＢＬＯＣＫＣＡＶＩＮＧＡＴＴＯＮＧＫＵＡＮＧＹＵＭＩＮＥ①ＺｈｏｕＡｉｍｉｎＣｈａｎｇｓｈａＩｎｓｔｉｔｕｔｅｏｆＭｉｎｉｎｇＲｅｓｅａｒｃｈ，Ｃｈａｎｇｓｈａ４１００１２...     

THEORETICAL DISCUSSION ON UNSTEADY FLOW OF FLUID DURING METAL ATOMIZATION

ＴＨＥＯＲＥＴＩＣＡＬＤＩＳＣＵＳＳＩＯＮＯＮＵＮＳＴＥＡＤＹＦＬＯＷＯＦＦＬＵＩＤＤＵＲＩＮＧＭＥＴＡＬＡＴＯＭＩＺＡＴＩＯＮ￥ＹＡＮＧＬｉｕｓｈｕａｎ;ＹＡＮＧＧｅｎｃａｎｇ;ＺＨＯＵＹａｏｈｅ（ＮｏｒｔｈｗｅｓｔｅｒｎＰｏｌｙｔｅｃｈｎｉｃａｌ...     

A CONTROVERTIBLE EQUATION IN “VIBRATION PROBLEMS IN ENGINEERING” BY TIMOSHENKOS

ＩＮＴＲＯＤＵＣＴＩＯＮ“ＶＩＢＲＡＴＩＯＮＰＲＯＢＬＥＭＳＩＮＥＮＧＩＮＥＥＲＩＮＧ（４ｔｈＥｄ）”,ｗｒｉｔｅｎｂｙＴｉｍｏｓｈｅｎｋｏＳ,ａｎＡｍｅｒｉｃａｎｍｅｃｈａｎｉｃｓｐｒｏｆｅｓｏｒ,ｉｓａｆａｍｏｕｓｗｏｒｋａｂｏｕｔｖｉｂｒａｔ...     

ADVANCED HIGH GRADIENT TECHNOLOGY FOR CASTING OF SUPERALLOY TURBINE BLADES

ＡＤＶＡＮＣＥＤＨＩＧＨＧＲＡＤＩＥＮＴＴＥＣＨＮＯＬＯＧＹＦＯＲＣＡＳＴＩＮＧＯＦＳＵＰＥＲＡＬＬＯＹＴＵＲＢＩＮＥＢＬＡＤＥＳＥ．Ｎ．Ｋａｂｌｏｖ（Ａｌｌ－ＲｕｓｓｉａｎＳｃｉｅｎｔｉｆｉｃＲｅｓｅａｒｃｈＩｎｓｔｉｔｕｔｅｏｆＡｖｉａｔｉｏｎＭ...     

CCWELD:A CIM system for robotic arc welding

ＣＣＷＥＬＤ：ＡＣＩＭｓｙｓｔｅｍｆｏｒｒｏｂｏｔｉｃａｒｃｗｅｌｄｉｎｇ￥ＫＯＮＧＹｕ；ＤＡＩＭｉｎｇ；ＷＵＬｉｎａｎｄＨＵＡＮＧＤｏｎｇｓｈｅｎｇ（ＷｅｌｄｉｎｇＤｅｐａｒｔｍｅｎｔ，ＨａｒｂｉｎＩｎｓｔｉｔｕｅｏｆｔｅｃｈｎｏｌｏｇｙ，Ｈａｒｂ...     

New methods of predicting dissimilar steel weld metal microstructures by Schaeffler Diagram(Part 2)

On the base of the methods of predicting weld metal microstructures of pearlitic dissimilar steel welded joints using austenitic type filler materials by Schaeffler Diagram, the other new methods of predicting and expressing weld metal microstructures of two kinds of dissimilar steel welded joints (pearlite/pearlite and austenite/pearlite) using austenitic filler materials by Schaeffler Diagram are suggested. Those new methods resolve some difficult problems which the microstructure kinds in two heterogeneous mixture zones of weld metal neighbouring two kinds of welded base metals are difficult to be accurately ascertained and the fluctuations of weld metal microstructures across fusion line are difficult to be conveniently expressed according to the traditional predicting method. The new predicting methods are more concise and practical.     

焊接工艺对TP304钢焊缝金属组织及性能的影响

针对TP304不锈钢,采用三种不同的焊接工艺方法,选取合适的焊接工艺参数,成功制备三组完整的焊接接头.通过X荧光化学成分分析、显微组织观察和显微硬度试验研究了不同焊接方法对TP304不锈钢焊缝金属组织和性能的影响.结果表明,不同焊接方法下焊缝合金成分有所差异,且分布不均;各焊层显微组织形态和晶粒大小差异较大;整个接头的硬度值分布并不均匀,焊缝高于热影响区,热影响区高于母材.三种焊接方法相比,TIG-MAG焊缝的硬度值最大,TIG-SMAW的最小.对于薄板不锈钢焊接,TIG-MAG组合焊法优选.     

Evaluation of creep rupture behaviour for weld joint and base metal of the Cr35Ni45Nb alloy

In order to investigate microstructure and creep rupture strength of a weld joint after aging, Cr35Ni45Nb alloy tubes were welded by the GTAW process of two-type filler metals. The tensile test, hardness and creep test were conducted to analyse the mechanical properties of the weld joint and base metal. The results show that the creep rupture time of the base metal at 1373?K is longer than a new weld joint, while the tensile properties of the base metal at room temperature are similar to a new weld joint. With aging, the microstructure of the weld metal and the base metal tended to be homogeneous, the creep rupture time of the weld joint improved and was similar to that of the base metal.     

焊接方法对1000MPa级熔敷金属组织及力学性能的影响

在相同热输入下分别采用熔化极活性气体保护焊(MAG)和钨极氩弧焊(TIG)进行1 000 MPa级熔敷金属试验,通过光学显微镜、透射电镜及断口分析等手段研究焊接方法对其组织和性能的影响. 结果表明,MAG焊熔敷效率明显高于TIG焊,MAG焊中出现了明显的"指状熔深". MAG焊熔敷金属及道间热影响区组织明显较TIG焊粗化. TIG焊熔敷金属组织细化、分布取向多样化且均匀分布的较多残余奥氏体是TIG焊低温冲击韧性优异的原因之一;MAG焊中生成大量非金属夹杂物易成为解理断裂起裂源,是导致熔敷金属冲击韧性恶化的因素之一. TIG焊力学性能明显优于MAG焊,这与焊接方法所导致的组织构成及夹杂物有直接关系.     

Influence of zirconium on microstructure and toughness of low-alloy steel weld metals

The influence of zirconium on microstructure and toughness of low-alloy steel weld metal was studied. Weld metals with different zirconium contents were obtained adding iron-zirconium alloy in the welding flux formulation. Weld metal chemical composition proved that zirconium was able to be transferred from the flux to the weld metal. The addition of zirconium refined the weld metal microstructure, increasing the acicular ferrite content. Weld metal toughness, determined by means of impact Charpy-V tests, showed that the zirconium addition is beneficial up to a content of 0.005 wt.%. Above this level, zirconium was not able to produce further microstructure refinement, although the toughness was reduced, possibly due to the formation of microconstituent such as the martensite-austenite constituent (M-A), which is considered to be deleterious to the weld metal toughness.     

碳钢焊接接头腐蚀行为分析

通过对焊接接头各区域显微组织观察以及开路电位、极化曲线和电偶腐蚀电流的测量,研究了两种热输入所得焊接接头各区域的腐蚀行为. 结果表明,热输入小的接头各区域耐蚀性由小到大依次为母材,焊缝,热影响区;热输入大的接头各区域耐蚀性由小到大依次为母材,热影响区,焊缝. 该结果与接头不同区域的显微组织相关. 两种接头总腐蚀速率相比,热输入大的接头耐蚀性较好.     

Ni元素对Cr-Ni-Mo系高强焊缝组织演化的影响

主要利用金相显微镜(OM)、高分辨热场扫描电镜(FEGSEM)附带能谱仪(EDX)、透射电镜(TEM)等手段对不同Ni元素含量的高强钢焊缝组织及成分进行了观察分析,阐明了焊缝成分对组织的影响.利用Thermol-Calc热力学软件对两种焊缝的凝固模式进行了探讨.结果表明,随着Ni元素含量的提高,高强钢焊缝由板条贝氏体和马氏体为主的组织变为板条更细小的马氏体与粗大联合贝氏体的混合组织,而且焊缝硬度大大提高.Ni元素含量的增加提高了焊缝强度,并保持了良好的低温韧性.Ni元素含量的提高改变了焊缝的凝固模式,直接由液态转变为奥氏体,造成合金元素Mn和Ni在枝晶间偏析.     

新型9Cr-1Mo钢搅拌摩擦焊接头组织及性能

采用钨铼合金搅拌工具对新型9Cr-1Mo钢进行搅拌摩擦焊工艺试验,探讨焊缝成形、组织及性能变化规律. 结果表明,在300和400 r/min的转速,50 mm/min的焊接速度下可获得无缺陷接头;焊缝主要由搅拌区和热力影响区组成,具有明显的马氏体淬硬组织特征;高温热影响区为淬硬马氏体和回火马氏体混合组织,低温热影响区为过回火马氏体组织. 焊缝区具有晶粒细化特征,其晶粒尺寸约为母材69.2%. 焊缝区产生明显硬化,最高硬度约为母材硬度值的2.0倍. 焊接接头抗拉强度达到母材98%以上,搅拌区和热影响区冲击吸收能量分别达到母材的77.8%和87.4%,表明搅拌摩擦焊接头仍具有较好强韧匹配.     

Relationships between microhardness,microstructure, and grain orientation in laser-welded joints with different welding speeds for Ti6Al4V titanium alloy

The microhardness curve trend and its relationships with microstructure and misorientation were analyzed to enhance the comprehension of the microstructure and mechanical property of micro-areas in Ti6Al4V laser-welded joints with different welding speeds. The microhardness measured on the fusion line (H_m) is the highest from the weld center to the base metal. H_m increases with increasing weld width in a welded joint and increasing degree of the non-uniformity in all studied welded joints. The microhardness decreases from the weld metal to the base metal with decreasing amount of martensite α’ and increasing amount of original α phase. When the microstructure is mainly composed of martensite α’, the microhardness changes with the cooling rate, grain size of the martensite, and peak values of the fraction of misorientation angle of the martensite in a wide weld metal zone or weld center at different welding speeds, whereas the difference is small in a narrow weld metal zone.     

镀锌薄板TIG拼焊的焊缝组织及成形性能

采用钨极惰性气体焊对镀锌薄板 SGCC 实施等厚拼焊,测试分析了拼焊板焊接接头的金相组织、显微硬度,并对拼焊板和母材试样进行杯突试验.结果表明,在拼焊过程中,母材的散热情况不同会造成焊缝金相组织在靠近母材的局部区域有很大差异.焊缝熔合区组织为粗的片状与块状先共析铁素体沿柱状晶界分布,晶内为魏氏体组织和片状珠光体,热影响区为块状的珠光体和铁素体,导致了焊缝及其热影响区的硬度均高于母材,对拼焊板的整体成形性能产生负面影响;同时,焊缝杯突值较母材有一定程度的降低,揭示其焊缝深冲性能低于母材.

Abstract：

The microstructure and micro-hardness of welded joint of SGCC by tungsten inert-gas (TIG) welding are studied, and the cupping test of Tailor-welded blank and base metal are studied.The results show that in the welding process, the microstructure of weld will have great diversity at local region closing parent metal because of the different cooling condition of the parent metal. The microstructure of welding fusion zone is massive sheet proeutectoid ferrite distribution along the columnar grain boundaries, intragranular organizations are Widmanstatten and sheet pearlite structure, and the microstructure in HAZ is massive pearlite and ferrite, which make the micro-hardness value of welding seam and HAZ higher than that of base metal and lead negative influence to the formability of Tailorwelded blank. The cupping value of weld seam reduces to some extent compared with that of base metal, which indicates that the formability of weld seam is not good as that of base metal.