45钢与YG6硬质合金的钎焊性能

本文通过对４５钢与ＹＧ６硬质合金的对接钎缝接头金相组织及强度分析，研究了钎焊加热时间、焊后冷却方法等对钎焊接头强度的影响，通过试验确定了一定工艺条件下的最佳钎焊时间及焊后冷却的几个工艺参数。     

27SiMn钢的亚温淬火工艺研究

研究了２７ＳｉＭｎ钢的亚温淬火工艺，着重讨论了亚温区的淬火温度选择及预处理组织对该钢亚温淬火效果的影响．测试了各种状态的静强度和冲击韧性．通过高压透射电子显微镜对试验钢微观组织的观察分析，得出该钢的亚温淬火加热温度在８６０℃，原始状态以调质态时性能较好．从经济的观点出发，采用锻造后正火态＋８６０℃淬火＋５５０℃高温回火的亚温处理可代替９２０℃淬火＋５００℃回火的原调质工艺．     

焊补缩孔热循环对奥-贝球铁HAZ组织与性能的影响

采用模拟焊接热循环方法 ,研究奥氏体区不同热循环对奥 贝球铁缩孔焊补热影响区 (HAZ)显微组织、抗拉强度、冲击韧性和断口形态的影响。试验结果表明 :模拟焊补缩孔HAZ中奥氏体区上限温度区显微组织变化大 ,力学性能差 ,是焊接接头的最薄弱环节 ,而在贝氏体转变温度区间内施加缓冷的热循环 ,奥氏体区内产生一定量奥 贝组织 ,力学性能改善 ,达到与奥 贝球铁母材的力学性能相匹配。     

不锈钢A—TIG焊活性剂的焊接性研究

利用自行研制的304不锈钢A－TIG焊活性剂进行了焊缝外观形貌、熔深效果、接头微观组织、化学成分及接头力学性能分析的焊接工艺试验，试验结果表明，使用活性剂可以使焊缝熔深比常规的TIG焊增加1－2倍，对8mm以下的不锈钢钢板对接无须开坡口，可一次焊接完成并且单面焊双面成型，焊缝表面成形良好，使用活性剂后接头微观组织、焊缝的化学成分和接头力学性能均不受影响。     

S690Q高强钢对接节点的焊后性能

通过试验研究了S690Q高强钢对接节点的焊后性能.利用手工电弧焊焊接了3个厚度为8 mm的S690Q高强钢对接节点,焊接过程中对3个节点分别采用不同的焊接热量.在微观层面上,用微观结构测试和微观硬度测试研究焊接对于节点的影响;在宏观层面上,通过拉伸试验研究焊接对于节点力学性能的影响.微观结构测试结果表明,S690Q高强...     

基于高炉焊接制造的BB503钢板焊接工艺研究

根据高炉炉壳生产实际,分别使用气电立焊和埋弧自动横焊两种焊接工艺对50 mm厚的BB503型炉壳用钢板进行焊接,对焊缝进行外观检查、无损探伤,对焊接接头进行拉伸、侧弯、冲击、硬度等性能测试,并对焊接热影响区的显微组织进行了观察和分析。结果表明,BB503炉壳用钢的气电立焊和埋弧自动横焊焊接接头抗拉强度和冲击吸收功均大于母材,具有优良的综合力学性能;焊缝区及热影响区的显微维氏硬度分布和热影响区的组织均匀性均显著优于传统的CO2气体保护焊和手工电弧焊接头。气电立焊和埋弧自动横焊工艺可以替代CO2气体保护焊和手工电弧焊工艺用于高炉炉壳焊接制造。     

不同淬回火工艺对40Cr钢微观组织与力学性能的影响

用金相显微镜、SEM电镜、拉伸试验及冲击试验等研究不同热处理工艺对40Cr钢微观组织与力学性能的影响。在微观组织上,不同热处理工艺的主要微观金相组织为回火索氏体且晶粒度等级为9级,而经亚温淬回火后还出现了铁素体。在力学性能上：860°C淬火+600°C回火工艺有利于提高40Cr钢的硬度、屈服强度及抗拉强度性能;860°C淬火+600°C回火+770°C亚温淬火+600°C回火可提高40Cr钢伸长率、断面收缩率和冲击韧性性能;对退火40Cr钢进行770°C亚温淬火+600°C回火后,钢的塑性和冲击韧性比淬回火+亚温淬回火差,硬度、屈服强度及抗拉强度比淬回火性能差。研究结果表明：淬回火可提高40Cr钢硬度和强度性能,淬回火+亚温淬回火可提升40Cr钢冲击韧性和塑性性能。     

铝-铝板和铝-镀锌钢板的电阻点焊研究

用电阻点焊方法实现了铝合金+铝合金薄板、铝合金+镀锌钢薄板在同种工艺参数下的有效连焊.通过对焊接接头进行力学性能、显微硬度、金相组织、界面成分的观察和测试,分析点焊接头形成机理和存在的各种质量问题,同种工艺下铝-铝接头与铝-镀锌钢接头相比,熔核尺寸较小,强度却大很多,从铝-铝点焊接头金相组织的观察可以看出焊缝和热影响区存在裂纹、未熔合、未完全融合、未焊透、夹渣和气孔等缺陷,而铝-镀锌钢接头中存在的缺陷较少.     

带电顶锻时间对高强钢闪光对焊接头组织及性能影响研究

研究了带电顶锻时间(St)对高强钢闪光对焊接头组织及性能的影响规律。结果表明,接头界面区和过热区主要为贝氏体+铁素体组织,其突出特点是晶粒明显粗化并存在高密度的位错。随着St增加,焊接热循环高温停留时间增加,冷却速度降低,这导致接头组织粗化,界面区铁素体量增加,接头硬度有降低的趋势。接头弯曲裂纹主要出现在界面区,带电顶锻时间(St)对弯曲裂纹长度具有较明显的影响。在本试验条件下,选择St=0.3s、0.7s有利于明显改善闪光对焊接头的弯曲性能。     

400MPa级超细晶粒钢焊接接头的低温韧性

利用CO2+Ar气体保护焊,分别采用单道焊接和双道焊接工艺对厚度为8 mm的400 MPa级超细晶粒钢钢板进行了焊接,采用系列冲击试验方法对焊接接头的低温韧性进行了研究。试验结果表明,在焊接接头中,焊逢位置低温韧性较差。由于双道焊较小的热输入,减小了焊缝及热影响区组织粗化,其焊接接头的低温韧性好于单道焊,并使热影响区面积变小。     

Development of 30Cr06A, a high strength cast steel and its welding ability

High performance hydraulic supports have a high requirement in strength, toughness and welding ability of socket ma- terial. Targeting this problem, we analyzed the properties of the high strength socket material 30Cr06, used in high performance hydraulic supports both at home and abroad and developed a new kind of high strength cast steel 30Cr06A, by making use of an orthogonal experiment, which provided the design conditions for its optimal composition. The result shows that the strength and toughness of the newly developed high strength cast steel 30Cr06A is much better than that of 30Cr06. Theoretical calculations, mechanical property tests and hardness distribution tests of welded joints were carried out for a study of the welding ability of the new material, which is proved to be very good. Therefore, this 30Cr06A material has been successfully used in the socket of high performance hydraulic support.     

Nb-Ti微合金钢大线能量焊接热影响区组织和韧性的研究

在使用大线能量焊接低合金高强度钢时,为了提高焊接热影响区（HAZ）韧性,通常加入Ti或Nb。利用正交分析进行9组冶炼试验研究,对Ti、Nb2种元素进行多种添加量的重点考察。利用轧制的实验钢进行大线能量气电立焊实验,检验这2种元素对钢板强度、钢板韧性、钢板焊接热影响区韧性的影响。实验结果表明,Nb对钢板的强度和韧性都有很大影响,随着Nb含量的提高,强度增加;当w（Nb）≥0．005％时,随Nb含量提高,韧性呈下降趋势;对钢板焊接热影响区韧性影响最大的是Ti,Ti能阻碍晶粒长大,使热影响区性能得到改善。     

高强钢焊接研究现状及发展趋势

在国家低碳节能发展趋势的推动下,高强钢得到广泛应用,高强钢焊接在交通运输、海洋工程等应用中显得越来越重要.从焊接工艺、焊接接头组织、力学性能等特点对国内外高强钢焊接方面的研究成果进行了综述,得出高强钢焊接接头各个区域的组织与性能不同,在不同焊接规范下相同区域的金相组织基本相似,熔合区因组织不均匀为最薄弱环节,指出防止高强钢热影响区的脆性破坏以及提高钢的韧性是今后高强钢焊接研究的重点.     

HQ100低合金高强度调质钢焊后热处理对焊缝金属韧性的影响

本文采用HQ100低合金高强度调质钢专用焊条,在焊态条件下研究了焊后进行脱氢、消除应力退火和正火等热处理对焊缝金属韧性的影响。试验结果表明,焊后对焊缝金属进行不同热处理时,其韧性均有不同程度的影响。采用合理的热处理方法和规范,可改善和提高焊缝金属的韧性,并取得了良好的效果,而且提出了最佳热处理规范,为实现HQ100高强度调质钢焊接生产应用提供了依据。     

Effect of welding process on the microstructure and properties of dissimilar weld joints between low alloy steel and duplex stainless steel

To obtain high-quality dissimilar weld joints, the processes of metal inert gas (MIG) welding and tungsten inert gas (TIG) welding for duplex stainless steel (DSS) and low alloy steel were compared in this paper. The microstructure and corrosion morphology of dissimilar weld joints were observed by scanning electron microscopy (SEM); the chemical compositions in different zones were detected by en-ergy-dispersive spectroscopy (EDS); the mechanical properties were measured by microhardness test, tensile test, and impact test; the corro-sion behavior was evaluated by polarization curves. Obvious concentration gradients of Ni and Cr exist between the fusion boundary and the type II boundary, where the hardness is much higher. The impact toughness of weld metal by MIG welding is higher than that by TIG weld-ing. The corrosion current density of TIG weld metal is higher than that of MIG weld metal in a 3.5wt% NaCl solution. Galvanic corrosion happens between low alloy steel and weld metal, revealing the weakness of low alloy steel in industrial service. The quality of joints pro-duced by MIG welding is better than that by TIG welding in mechanical performance and corrosion resistance. MIG welding with the filler metal ER2009 is the suitable welding process for dissimilar metals jointing between UNS S31803 duplex stainless steel and low alloy steel in practical application.     

纤维高性能混凝土工作性能与韧性的试验研究

目的 揭示高耐碱玻璃纤维[ARGF（H）]与混杂纤维对高性能混凝土工作性能与弯曲韧性的影响，以拓展它们的结构用途．方法 参照国际上先进的试验方法和标准，按不同的纤维掺量设计了多组玻璃纤维、钢纤维（SF）以及混杂纤维混凝土试件，进行了大量工作性能、含气量、抗压强度和弯曲韧性的试验．结果 掺加纤维对高性能混凝土的工作性能、抗压强度无明显影响。钢纤维和混杂纤维均可明显提高混凝土的韧性．结论 玻璃纤维对混凝土的韧性有一定的提高，与钢纤维混杂可充分发挥SF提高韧性及ARGF（H）抵抗收缩裂缝的功效，在实际工程中具有性能与成本的优势。     

Mg-Ti复合脱氧对低碳微合金钢组织性能的影响

通过焊接热模拟和冲击韧性试验,研究了Mg-Ti脱氧和Al脱氧在大线能量焊接热循环条件下对低碳微合金钢粗晶区组织性能的影响。结果表明,Mg-Ti脱氧钢粗晶区的组织主要是针状铁素体（AF）和少量的多边形铁素体,Al脱氧钢粗晶区的组织主要是低碳贝氏体＋大量的块状铁素体。对Mg-Ti脱氧钢和Al脱氧钢在不同焊接热循环下的冲击韧性进行研究,结果表明随着焊接热输入量的增大,两种脱氧钢的冲击韧性都有所下降,但是从总体上来说Mg-Ti脱氧钢粗晶区的冲击韧性远远高出Al脱氧钢粗晶区的冲击韧性。     

Microstructure and mechanical properties of high-Cr cast iron bars reinforced Hadfield steel matrix composites

To obtain the compatible material of high hardness and high toughness, Hadfield steel matrix composites, reinforced by high-Cr cast iron bars made of flux-cored welding wires, which were inserted into the Hadfield steel melt, were investigated. The mechanical properties of three materials, i e, composites for as-cast and quenching-water condition, as well as Hadfield steel, were compared. The results show that the alloy powder inside flux-cored welding wires can be melted by the heat capacity of Hadfield steel melt and solidify into high-Cr cast iron bars. The impact toughness of the composite for quenching-water condition is higher than that of the composite for as-cast condition and is lower than that of the Hadfield steel, but it can still meet the requirements of hardness and toughness in industrial application. Regardless of load variation, composite for quenching-water condition shows better wear resistance than those of the composite for as-cast condition and Hadfield steel. The modified fracture toughness and wear resistance of composites are attributed to not only the combining actions of Hadfield steel matrix and high-Cr cast iron bars, but also the effect of heat treatment.     

Effects of welding wire composition and welding process on the weld metal toughness of submerged arc welded pipeline steel

The effects of alloying elements in welding wires and submerged arc welding process on the microstructures and low-temperature impact toughness of weld metals have been investigated.The results indicate that the optimal contents of alloying elements in welding wires can improve the low-temperature impact toughness of weld metals because the proentectoid ferrite and bainite formations can be suppressed,and the fraction of acicular ferrite increases.However,the contents of alloying elements need to vary along with the welding heat input.With the increase in welding heat input,the contents of alloying elements in welding wires need to be increased accordingly.The microstructures mainly consisting of acicular ferrite can be obtained in weld metals after four-wire submerged arc welding using the wires with a low carbon content and appropriate contents of Mn,Mo,Ti-B,Cu,Ni,and RE,resulting in the high low-temperature impact toughness of weld metals.