共查询到20条相似文献,搜索用时 312 毫秒
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李宁;叶建林;张成 《金属材料与冶金工程》2013,(6):15-18
采用GTAW+SMAW组合方法焊接了N02201/Q345R镍钢复合板,截取两组同规格试板,其中一组为焊态,另一组进行550℃保温4 h热处理。通过拉伸试验和弯曲试验测试并对比了接头力学性能,同时利用OM对焊接接头微观组织进行表征对比。结果表明:焊态和热处理态N02201/Q345R复合板接头力学性能均满足标准和使用要求,热处理后接头抗拉强度仅降低49 MPa;N02201/Q345R复合板接头焊态和热处理态钢侧为铁素体和珠光体组织,镍侧为单相奥氏体,镍钢界面存在镍元素向钢侧扩散现象,焊态扩散层宽度约为0~25μm,热处理态扩散层宽度约为100~160μm。 相似文献
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焊接热影响区(HAZ)的微观组织很大程度上决定了钢材焊接处的力学性能。为了掌握含钛微合金钢Q345B在不同焊接线能量下热影响区的微观组织及性能演变规律,采用Gleeble 3500热模拟试验机,对含钛微合金钢Q345B焊接过程中热影响区的组织演变进行模拟试验研究,分析了冷却速率对热影响区的微观组织及冲击韧性的影响。结果表明,大线能量焊接低冷速下热影响区组织以粒状贝氏体为主,t8/5为120 s时,析出针状铁素体,针状铁素体的出现有利于焊接热影响区冲击韧性的提升。 相似文献
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针对压力容器用Q345R钢板正火态条件下的微观组织和力学性能进行研究,通过优化成分设计、合理控制冶炼、轧制及热处理工艺,成功开发了正火态压力容器用高强度Q345R用钢。试验结果表明:正火态的钢板组织更均匀致密,冲击韧性优异,拉伸性能更稳定,满足压力容器相关标准要求。 相似文献
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文章对比分析了稀土元素对低合金高强度结构钢Q345E焊接接头力学性能及金相组织的影响,从稀土元素对Q345E的晶粒度和夹杂物控制方面分析了稀土对母材及焊缝疲劳性能的影响。 相似文献
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低合金高强钢因其应用环境以及使用条件的特殊性,常常需要具有良好的力学性能。微合金化结合一定的热处理工艺,可以有效提高低合金高强钢的性能。研究钛微合金化及热处理工艺对低合金高强钢组织和性能的影响规律及作用机理,对提高材料的性能、扩大材料的应用具有重要的意义。以C-Mn-Ti系Q355B板坯的试制过程为例,研究了钛微合金化冶金成分及轧制工艺控制对材料显微组织和力学性能的影响规律;对比了4种不同轧制工艺条件下所生产钢板的力学性能和金相微观组织;并分析了材料的强化机制。0℃和20℃时Q355B板的低温冲击性能、屈服强度和冷弯性能分析结果表明,冶炼过程中形成的较大尺寸的TiN和链状的Ti4C2S2对钢板的塑性和韧性均有负面影响;Ti微合金化后的钢板晶粒度均在9级以上;精开轧温度低于890℃,终冷温度在660±20℃波动时,钢板的综合力学性能最好。 相似文献
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M. Manikandan N. Arivazhagan M. Arivarasu K. Mageshkumar Deva N. Rajan B. Arul Murugan P. Prasanth S. Sukumar R. Vimalanathan 《Transactions of the Indian Institute of Metals》2017,70(3):661-669
The present work investigates the microstructure and mechanical properties of alloy C-276 fabricated by continuous and pulsed current gas tungsten arc welding process and by employing ER2553 filler wire. Optical and scanning electron microscopic analyses were carried out to study the microstructures of weldments produced. Energy dispersive X-ray spectroscopy (EDS) was performed to investigate the formation of secondary phases in the weldments. The results disclosed that pulsed current gas tungsten arc welding showed refined microstructure compared to continuous current gas tungsten arc welding. SEM/EDS analysis revealed the segregation of Mo in the weld interface regions in both the welding techniques. The extent of microsegregation reduced the strength and toughness of the weld joint compared to the base metal. Bend test revealed cracks in the weld interface region in both the weldments. 相似文献
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通过连续冷却相转变行为的研究,利用试验轧机成功试制了24mm厚,屈服强度460MPa级耐候钢板,并分析了钢板微观组织、力学性能、腐蚀性能以及焊接性能。连续相转变行为和钢板试制结果表明:精轧温度不大于850℃,厚度压下率不小于0.6,冷速为4~15℃/s和终冷温度不大于465℃可得到以针状铁素体(3~10μm)和多边形铁素体(5~15μm)为主的钢板,其屈服强度不小于480MPa,抗拉强度不小于635MPa,伸长率不小于23%,-40℃冲击功不小于209J。对试制钢板进行了热输入量为72kJ/cm的双丝埋弧焊接试验,无焊前预热和焊后热处理,得到了无缺陷焊接接头,焊接热影响区-40℃冲击功不小于100J;粗晶区的高韧性与其晶内铁素体为主以及少量晶界铁素体和上贝氏体的微观组织有关。72h周浸试验结果表明:试制钢种的耐大气腐蚀能力比普碳钢Q345B提高了46%。 相似文献
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《钢铁研究学报(英文版)》2011,(Z1):983-986
590 MPa automobile beam steel strips are used mainly to manufacture the longitudinal beam of trucks.It’s welding properties are critical to the safety of truck.The microstructure and mechanical properties of welding joints processed by CO 2 arc welding with different welding parameters were studied.The results showed that the welding joints were weak when welding heat input were small and the non metal inclusions were found in the weld joints when welding heat input are big.The quality of the welding joints is good enough at 170A of the arc current and 24V of the arc voltage.Keeping the other welding parameters fixed,the incomplete fusion defect occurred in the welding joint with backward welding,but the quality of the welding joint is good with forward welding. 相似文献
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Steeliswidelyusedbecauseofitsgoodcompre hensive properties ,plentyofresourceandlowerprice .Thestrengthandtoughnessaretwoimpor tantpropertiesofsteels ,andpeoplemakeeffortstoincreasetheirvalues .Addingalloyingelementandcontrollingmicrostructurearetwobasicwaystoac complishtheaim .Therefinedmicrostructureob tainedbyprocessingtechniqueenablesthestrengthandtoughnessofsteeltobeincreasedwithoutaddingalloyingelementandtheratioofperformance costtobeincreased .Theultra finegrainedsteelshavefer ritegrains… 相似文献
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P. K. Ghosh S. R. Gupta H. S. Randhawa 《Metallurgical and Materials Transactions A》2000,31(9):2247-2259
The performance of the pulsed-current gas metal arc welding (GMAW) process for vertical-up weld deposition of steel has been
found to be superior over the use of the short-circuiting arc GMAW process with respect to the tensile, impact, and fatigue
properties of the weld joint. The microstructure, weld geometry, and mechanical properties of a pulsed-current weld joint
are largely governed by the pulse parameters, and correlate well to the factor φ, defined as a summarized influence of pulse parameters such as peak current, base current, pulse-off time, and pulse frequency.
The increase of φ has been found favorable to refine the microstructure and enhance the tensile strength, C
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toughness, and fatigue life of a weld joint. The fatigue life of a short-circuiting arc weld joint has been found to be markedly
reduced due to the presence of an undercut at the weld toe and incomplete side-wall fusion of the base material. 相似文献
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V. Maduraimuthu M. Vasudevan V. Muthupandi A. K. Bhaduri T. Jayakumar 《Metallurgical and Materials Transactions B》2012,43(1):123-132
A novel variant of tungsten inert gas (TIG) welding called activated-TIG (A-TIG) welding, which uses a thin layer of activated
flux coating applied on the joint area prior to welding, is known to enhance the depth of penetration during autogenous TIG
welding and overcomes the limitation associated with TIG welding of modified 9Cr-1Mo steels. Therefore, it is necessary to
develop a specific activated flux for enhancing the depth of penetration during autogeneous TIG welding of modified 9Cr-1Mo
steel. In the current work, activated flux composition is optimized to achieve 6 mm depth of penetration in single-pass TIG
welding at minimum heat input possible. Then square butt weld joints are made for 6-mm-thick and 10-mm-thick plates using
the optimized flux. The effect of flux on the microstructure, mechanical properties, and residual stresses of the A-TIG weld
joint is studied by comparing it with that of the weld joints made by conventional multipass TIG welding process using matching
filler wire. Welded microstructure in the A-TIG weld joint is coarser because of the higher peak temperature in A-TIG welding
process compared with that of multipass TIG weld joint made by a conventional TIG welding process. Transverse strength properties
of the modified 9Cr-1Mo steel weld produced by A-TIG welding exceeded the minimum specified strength values of the base materials.
The average toughness values of A-TIG weld joints are lower compared with that of the base metal and multipass weld joints
due to the presence of δ-ferrite and inclusions in the weld metal caused by the flux. Compressive residual stresses are observed in the fusion zone
of A-TIG weld joint, whereas tensile residual stresses are observed in the multipass TIG weld joint. 相似文献
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P. Vasantharaja M. Vasudevan V. Maduraimuthu 《Transactions of the Indian Institute of Metals》2018,71(1):127-137
The present study aims at understanding the effect of various arc welding processes on the evolution of microstructure, mechanical properties, residual stresses and distortion in 9 mm thick type 316LN austenitic stainless steel weld joints. Weld joints of type 316LN stainless steel were fabricated by three different arc welding processes which were commonly employed in the nuclear industry. All the weld joints passed radiographic examination. Microstructural characterization was done using optical and scanning electron microscope. Volume fraction of δ-ferrite was lowest in the A-TIG weld joint. The A-TIG welded joint exhibited adequate strength and maximum impact toughness values in comparison to that of weld joints made by SMAW and FCAW processes. The A-TIG weld joint was found to exhibit lowest residual stresses and distortion compared to that of other welding processes. This was attributed to lower weld metal volume and hence reduced shrinkage in the A-TIG weld joint compared to that of weld joints made by FCAW and SMAW processes which involved v-groove with filler metal addition. Therefore, type 316LN stainless steel A-TIG weld joint consisting of lower δ-ferrite, adequate strength, high impact toughness, lower residual stresses and distortion was suited better for elevated temperature service compared to that of SMAW and FCAW weld joints. 相似文献
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A. Grill 《Metallurgical and Materials Transactions B》1981,12(1):187-192
The welding process employed for bonding metals by melting and solidification produces a joint which is generally inhomogeneous.
The micro structure of the fused zone and its adjacent heat affected zone, HAZ, is usually different from the microstructure
of the parent metal, obtained by mechanical working or heat treatment. The fused zone is usually composed of coarse columnar
grains characteristic of as-cast structures. If the parent metal was originally cold-worked, recrystallization will occur
in the HAZ, producing a coarse grained structure. As a result of the effect of the microstructure on the mechanical properties
of the weld, the obtained joint may be weaker than the rest of the structure which was not affected by the heat of the welding.
Although in some cases it is possible to improve the properties of the weld by post-welding heat treatment, different methods
are tried in order to improve the microstructure directly during the welding process. 相似文献