航空用新型超高强度钢16NiCo

１６ＮｉＣｏ是可焊接超高强度钢，主要成分是０．１６Ｃ－２Ｃｒ－１０Ｎｉ－１Ｍｏ－１４Ｃｏ。靠二次硬化获得所需强度。使用状态下的基体组织为板条马氏体，主要强化相是沿位错线分布的Ｍ＿２Ｃ。力学性能的典型值为抗拉强度σ＿ｂ１７４０ＭＰａ，断裂韧度Ｋ＿（ＩＣ）值为１５３ＭＰａ，Ｋ＿（ＩＳＣＣ）值为８２ＭＰａ。工艺性能良好，可用于制造受力接头、平尾大轴、着陆钩和起落架零件。     

新型高合金二次硬化超高强度钢的发展

本文介绍了国外高Ｃｏ，Ｎｉ的超高强度钢ＨＹ１８０、ＡＦ１４１０和ＡｅｒＭｅｔ１００钢的进展，与其它超高强度钢相比，ＡｅｒＭｅｔ１００超高强度钢具有更突出的综合性能，高强度、高强度、高断裂韧性，优异的抗应力腐蚀开裂和抗疲劳性能，此钢具有广泛的应用前景。     

18Mn2CrMoBA钢的性能及应用前景EI

本文简要介绍了１８Ｍｎ２ＣｒＭｏＢＡ高强度钢的工艺性能，并对今后的进一步应用提出看法。     

Cr—Mo耐热钢焊接接头蠕变过程中Mo2C变化规律的研究

研究了２．２５Ｃｒ－１Ｍｏ钢焊接接头蠕变时母材和焊缝中的Ｍｏ２Ｃ的变化规律。试验结果表明,在焊接接头中Ｍｏ２Ｃ呈针状、片状和碎屑头三种形貌,但主要以针状形态析出,当以片状或件屑状析出时,会使材料的蠕变抗力降低。针状Ｍｏ２Ｃ在铁素体中比在贝氏体中尺寸粗大。     

底注钢锭模设计及特种Cr-Ni、Cr-Mo钢锻件的试制

指出了Ｃｒ Ｍｏ钢、Ｃｒ Ｎｉ钢等特种钢锻件生产中存在的工艺问题。设计了专用的底注钢锭模,试制出符合ＡＳＴＭＡ１８２－７８标准要求的Ｃｒ９Ｍｏ、１．２５Ｃｒ０．５Ｍｏ、Ｃｒ２５Ｎｉ２０钢锻件,解决了这些特种钢的原材料供应难题。     

离子渗氮对耐磨性的影响

对四种离子渗氮工艺条件下的３８ＣｒＭｏＡｌ新渗氮钢进行了磨损试验研究。通过Ｘ射线衍射表面相结构分析以及测量表明硬度，截面硬度梯度，化合物层厚度和渗氮层深度等试验结果表明，离子渗氮前的原始组织对３０Ｃｒ２ＭｏＶ钢耐磨性影响较小，而对３８ＣｒＭｏＡｌ钢的耐磨性影响较大。离子渗氮工艺条件对这两种钢耐磨性具有一最佳值。     

40Cr钢焊接区表面高频淬火后的超塑焊接

探讨了４０Ｃｒ钢焊接区表面局部高频淬火后超塑焊接的可行性及影响因素，并对接头组织进行了观察和分析。试验结果表明，焊接区局部高频淬火后的４０Ｃｒ钢在其超塑变形温度及应变速率范围内，经短时超塑压接其接头抗拉强度可达到母材之值。     

超高强度钢连续冷却组织和时效反应的研究EI

观察分析了冷却速度对低合金超高强度钢（４０ＣｒＭｎＳｉＭｏＶＡ）精细组织的影响。结果表明，在冷却、低温等温（或回火）过程中，钢显微组织中的马氏体或贝氏体存在时效阶段。其组织特征为呢纹花样。α和ε间的取向不满足Ｊａｃｋ关系，它属一种新的取向关系。过渡型碳化物可直接从呢纹花样区析出。     

Al对含P,Mo奥氏体不锈钢应力腐蚀性能的影响

用点焊接试验方法评价了合金元素Ａｌ对含Ｐ和Ｍｏ奥氏体不锈钢应力腐蚀破裂性能的影响。结果表明，单独添加Ａｌ没有改善应力腐蚀破裂性能，而复合添加Ａｌ和Ｃｕ有效地提高了抗应力腐蚀性能。１４Ｃｒ－１６Ｎｉ－２Ｃｕ－３Ａｌ钢中添加Ｍｏ，虽然降低应力腐蚀性能，但影响较小。含０．３％Ｍｏ时应力腐蚀破裂临界温度可达１２０℃。ＡＥＳ分析表明，Ａｌ和Ｃｕ元素在表面膜中富集。Ａｌ和ｃｕ的联合作用使钢表面膜的钝化能力得到加强，从而提高了抗应力腐蚀性能。     

1Cr5Mo钢管道焊后热处理质量评定指标研究

以１Ｃｒ５Ｍｏ钢管道为例,讨论了焊后热处理质量评定指标,通过对实际接头不同热处理制度下及热处理前后残余应力,硬度的测定和显微组织的观察,认为对于１Ｃｒ５Ｍｏ钢,以接头的硬度最大值２２５ＨＢ作为热处理质量评定指标较为恰当。在焊接质量保证合格的前提下,一般可仅校验热处理温度记录曲线合格,判定热处理质量合格。     

超高强钢的摩擦焊工艺研究

目的研究某产品摩擦焊的工艺性能。方法研究了超高强钢45CrNiMo1VA钢在不同摩擦焊接工艺参数下的接头组织与性能,以及在不同热处理回火温度下对焊接接头强度的影响。结果在合适的工艺参数下,45CrNiMo1VA钢的高韧性可以有效保证焊接接头韧性,满足产品高指标的要求,使焊接接头组织具有良好的组织性能,焊后热处理工艺的正确确定是保证焊缝组织性能与母材组织性能的重要保证。结论试验证明超高强钢(45CrNiMo1VA)完全可以应用于摩擦焊生产中,并能获得理想的性能指标。     

Rißfortschritt in ultrafesten Stählen und deren Schweißverbindungen bei dynamischer Beanspruchung

Crack propagation in ultra-high-strength steels and their welded joints under dynamic loading . Reported are results of investigation into the propagation of cracks in the base metal and weld metal of an ultra-high-strength steel. The material used in the investigations was a Ni? Co? Mo? alloy maraging steel with a yield point of 170 kp/mm². The steel was arc welded and TIG welded. The joints exhibited a drop of static strength in the range of 5 to 8 percent related to the base metal. Under zero-to-tension stress cycles the fatigue strength corresponded that of other high-strength steels, under tension-compression stress cycles the steel exhibited a higher fatigue strength. It was possible to show striations with the aid of scanning microscopy. Comparing the track propagation calculated in the microscopic range with the results obtained from the crack growth curves produced approximate agreement.     

Effect of welding wire and groove angle on mechanical properties of high strength steel welded joints

Mechanical properties of high strength steel welded joints strictly depend on the welding process, the filler material composition and the welding geometry. This study investigates the effects of using cored and solid welding wires and implementing various groove angles on the mechanical performance of weld joints which were fabricated employing the gas metal arc welding process. It was found that weld joints of low alloy, high strength steels using low alloy steel cored welding wires exhibited higher tensile strength than that of low alloy steel solid wire and chromium‐nickel steel bare welding wire when the method of gas metal arc welding is employed. The effect of groove angle on the strength and toughness of V‐groove and double V‐groove butt‐joints was investigated. V‐groove joints, with higher tensile strength than double V‐groove joints in the whole range of groove angles, were superior in toughness for small groove angles, but impact toughness values of both joints were comparable for large angles. The effect of heat input and cooling rate on the weld microstructure and weld strength was also investigated by performing thermal analysis employing the commercial software ANSYS. It was concluded that cooling rate and solidification growth rate determined the microstructure of the weld zone which had great consequences in regard to mechanical properties.     

结构钢焊接匹配性研究进展

对结构钢焊接的高强匹配和低强匹配两种技术路线的发展进行了综述。在焊缝金属具有足够韧性的情况下,高强匹配能利用焊缝金属的高强度降低位于焊缝中裂纹的扩展驱动力、从而有利于焊接接头抗断性能的提高;随着结构钢强度的提高,焊接冷裂纹敏感性增大、焊缝韧性降低,采用焊接裂纹敏感性相对较低、焊缝金属塑韧性相对较高的低强匹配焊接技术能较好的控制焊接冷裂纹的产生并保证接头的抗断性能。     

超级双相不锈钢2507焊接工艺研究现状

主要梳理和综述了超级双相不锈钢2507焊接方面的研究工作,从而对超级双相不锈钢2507焊接工艺进行指导。从超级双相不锈钢2507焊接工艺、焊接接头两相比例调节两个维度进行综述,其中,超级双相不锈钢2507焊接工艺部分从钨极氩弧焊、埋弧焊、等离子弧焊、激光焊、电子束焊、激光-电弧复合焊这6种焊接工艺开展评述,焊接接头两相比例调节部分从调整焊接热输入、焊后热处理、添加合金元素镍或氮3个方面进行评述。结合国内外研究现状,探讨了超级双相不锈钢焊接如何控制接头两相比例这一关键问题。研究现状表明:钨极氩弧焊、等离子弧焊和激光焊可以较好地实现超级双相不锈钢优质焊接;添加合金元素镍或氮是调控焊接接头两相比例的重要手段。开展超级双相不锈钢2507焊接工艺研究现状的综述具有重要意义,向熔池过渡合金元素的高能量密度焊接工艺可能是超级双相不锈钢焊接的优选技术。     

Dissimilar joining of galvanized high-strength steel to aluminum alloy in a zero-gap lap joint configuration by two-pass laser welding

A welding procedure based on using two-pass laser scans is introduced for dissimilar joining of overlapped galvanized high-strength dual-phase (DP) steel DP590 to aluminum alloy (AA) 6061 sheets. The first pass is based on a defocused laser spot that scans across the top of the two overlapped sheets and heats the zinc coating at the faying surface to be melted and partially vaporized, while the second pass is executed with a focused laser spot in order to perform the welding. Completely defect-free galvanized steel to aluminum lap joints were obtained by using this two-pass laser welding procedure. An on-line machine vision system was applied to monitor the keyhole dynamics during the laser welding process. An energy-dispersive X-ray spectroscopy (EDS) was carried out to determine the atomic percent of zinc, aluminum, and iron in the galvanized steel to aluminum lap joints. Mechanical testing and micro-hardness test were conducted to evaluate the mechanical properties of the galvanized steel to aluminum lap joints. The experimental results showed that the lap joint of galvanized steel to aluminum obtained by the two-pass laser welding approach had a higher failure value than those joints obtained when the zinc at the faying surface was mechanically removed under the same welding speed and laser power.     

316L/X65复合管弧焊工艺研究

采用手工钨极氩弧焊和电弧焊实现了316L/X65双合金复合管的对接焊接。为了研究复合管的焊接工艺,对焊接接头进行了硬度、拉伸和冲击测试,利用光学显微镜、扫描电镜和能谱仪分析了接头的微观结构和成分特点,并对接头进行了电化学实验。结果表明:复合管焊缝由碳钢层、扩散层、过渡层和不锈钢层组成,碳钢层主要为针状铁素体,扩散层出现了马氏体组织,过渡层和不锈钢层焊缝中铁素体呈骨架或蠕虫状分布在奥氏体晶界;本实验焊接工艺下,覆层未受到碳钢层的稀释,化学成分与母材基本一致,但耐蚀性略有降低;焊接接头各项力学性能良好。     

船板钢焊接接头的断裂失效行为及GTN模型的数值分析

船舶钢结构皆采用焊接方法建造而成,在实际工况及环境载荷作用下,焊接接头的力学性能及其断裂强度,直接影响船舶整体结构的强度和寿命。该文针对常用的船板钢材料(Q345和Q690),首先对母材进行单向拉伸试验,获得其各自的应力-应变曲线,进而评估其断裂性能;基于Gurson-Tvergaard-Needleman (GTN)损伤模型,通过程序代码的调试和一系列的数值模拟分析,提出了母材本构关系的表达函数及最优GTN模型参数,且与实测的应力-应变曲线高度吻合。同时,针对满足焊接规范要求的船板钢对接焊接头,进行了单向拉伸试验获得其应力-应变曲线;考虑焊缝微观缺陷以及焊接残余应力的影响,提出修正GTN损伤模型中的初始空穴体积分数f₀和材料的幂函数塑性强化参数,预测焊接接头的断裂强度,且与试验测量数据吻合一致。     

Effect of welding processes on fatigue crack growth behaviour of AISI 409M ferritic stainless steel joints fabricated using duplex stainless steel fillers

The present investigation aims to study the effect of welding processes such as shielded metal arc welding (SMAW), gas metal arc welding (GMAW) and gas tungsten arc welding (GTAW) on fatigue crack growth behaviour of the ferritic stainless steel (FSS) conforming to AISI 409M grade. Rolled plates of 4 mm thickness were used as the base material and AISI 2209 grade duplex stainless steel (DSS) was used as filler metal, for preparing single pass butt welded joints. Centre cracked tensile (CCT) specimens were used to evaluate the fatigue crack growth behaviour. From this investigation, it is found that the GTAW joints showed superior fatigue crack growth resistance compared with SMAW and GMAW joints. The reasons for the superior performance were discussed in detail.     

Structure and properties of friction welds between high-speed steel and medium-carbon steel for bimetal tools

Abstract

Bimetal joints between high-speed steel and medium-carbon steel are often required in the tool industry. Friction welds were made between this dissimilar combination of materials and the joint behaviour was evaluated under conditions appropriate to the intended service applications. The welding was carried out under optimized conditions, the joints were subjected to a heat treatment schedule that is usual in service, and the joint performance was estimated in dynamic torsion. The structural changes occurring during welding and during the subsequent heat treatments were followed by optical metallography and hardness testing. The results show that, although decarburization occurs during post-weld annealing in the medium-carbon steel adjacent to the weld, the joint properties are adequate for moderately severe drilling conditions. Friction welding may thus prove to be an acceptable process for producing such joints.

MST/393