共查询到19条相似文献,搜索用时 171 毫秒
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分别选用TGS-2CM焊丝和ER309L焊丝,采用自动TIG焊对35CrMoA+S275NL异种钢进行焊接,分析了焊缝和热影响区金属的显微组织,并测试了焊接接头的显微硬度。结果表明,两种焊丝对异种金属35CrMoA+S275NL焊接均能获得良好的焊接接头,但用ER309L焊丝焊接所得焊缝金属的组织与性能更适合在低温条件下且存在交变载荷作用的焊接零部件。 相似文献
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采用三种不同焊接方法,即手工焊、氩弧焊(TIG焊)、CO2气体保护焊,对40Mn2钢在热轧状态及焊后200℃回火状态的焊接接头显微组织和硬度分布进行了研究.结果表明:热轧状态下,三种焊接工艺所得焊缝组织均由粗大柱状晶、针状及块状铁素体和珠光体组织组成;焊后200℃回火状态的三种焊接工艺所得焊缝组织明显比其未经回火的组织细小;CO2气体保护焊焊接接头显微组织更细小、均匀,且魏氏组织(针状铁素体)等脆性相的数量较少;焊缝熔合区都有魏氏组织存在,但级别各不相同;热影响区组织均为细小的铁素体与片状珠光体组成.三种焊接工艺中,焊缝硬度值虽都有波动,但都在硬度允许范围内.故CO2气体保护焊+焊后200℃回火焊缝显微组织及硬度分布有最佳配合,为在本实验条件下的最佳焊接工艺. 相似文献
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焊接工艺对TP304钢焊缝金属组织及性能的影响 总被引:4,自引:3,他引:1
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. 相似文献
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用自制的XMH-160型线性摩擦焊机进行了TC4线性摩擦焊试验研究.利用前期试验优化的工艺参数进行焊接,获得了100%焊合率的焊接接头.对焊后试件进行了拉伸性能试验,拉伸试件均断在远离焊缝的母材区,表明接头的力学性能指标超过了母材.对接头解剖后进行了组织分析和显微硬度测试,发现焊缝中部宽约60μm,边缘宽约110μm,焊缝两边的金属流线组织呈对称分布;焊缝中心区为α β超细晶组织,近缝区为不同程度的α β变形组织,但晶粒未明显长大;焊缝的显微硬度明显高于母材.接头组织的上述变化特点是拉伸力学性能和显微硬度均高于母材的主要原因. 相似文献
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采用真空电子束焊工艺焊接6082铝合金,通过金相组织观察、断口扫描分析、拉伸试验和显微硬度测试对获得的接头进行显微组织和力学性能的研究.结果表明,采用圆形扫描方式,电子束流为105 mA,焊接速度为1500 mm/min的工艺条件下,获得接头具有最佳的力学性能,接头抗拉强度达到母材本身强度的81%左右.接头金相组织观察表明,焊缝金属为细小的等轴晶组织,在晶界及晶粒内分布着较多的强化相;接头焊缝XRD相结构分析证实,焊缝金属基体为α - Al,并含有β(Mg2Si)强化相和单质Si相;拉伸断口扫描观察显示,接头断口表面分布大量的韧窝,韧窝尺寸小且分布均匀,呈明显韧性断裂特征. 相似文献
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摘要: X80钢管道铜衬垫外根焊全自动焊接过程中,装配条件的改变对铜衬垫熔化导致的Cu元素向焊缝扩散及接头的力学性能具有一定影响。系统地分析了不同对口间隙与错边量对X80钢管道铜衬垫外根焊全自动电弧焊接接头的Cu元素含量和力学性能的影响。通过能谱分析和化学成分分析对焊缝中的Cu元素含量进行表征,利用拉伸试验、常温冲击试验及背弯和侧弯试验测量不同装配条件下接头的力学性能。结果表明,对口间隙大于1.0 mm或错边量大于3.0 mm的装配条件下焊缝成形质量差;在保证获得良好焊缝成形的条件下,对口间隙和错边量的增大会导致根焊层底部Cu含量的增加,但不同条件下焊缝的Cu元素含量均低于0.5%(质量分数),铜衬垫的使用对焊缝Cu元素含量影响不大。接头的力学性能测试结果显示,不同装配条件下得到的接头抗拉强度和冲击韧性差异较小,且拉伸试样均断裂在母材位置,热影响区的冲击韧性优于焊缝,而对口间隙和错边量的增加会降低接头的弯曲性能。
创新点: 研究了不同装配条件对X80钢管道铜衬垫外根焊接头的Cu元素含量和力学性能的影响,发现对口间隙和错边量的增大会导致根焊层底部Cu元素含量的少量增加及接头弯曲性能的下降,而对接头的抗拉强度及冲击韧性无显著影响。 相似文献
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V. Balasubramanian V. Ravisankar G. Madhusudhan Reddy 《Journal of Materials Engineering and Performance》2008,17(2):224-233
This article reports the effect of postweld aging treatment on fatigue behavior of pulsed current welded AA 7075 aluminum
alloy joints. AA7075 aluminum alloy (Al-Zn-Mg-Cu alloy) has gathered wide acceptance in the fabrication of light weight structures
requiring high strength-to weight ratio, such as transportable bridge girders, military vehicles, road tankers, and railway
transport systems. The preferred welding processes of AA7075 aluminum alloy are frequently gas tungsten arc welding (GTAW)
process and gas metal arc welding (GMAW) process due to their comparatively easier applicability and better economy. Weld
fusion zones typically exhibit coarse columnar grains because of the prevailing thermal conditions during weld metal solidification.
This often results inferior weld mechanical properties and poor resistance to hot cracking. In this investigation, an attempt
has been made to refine the fusion zone grains by applying pulsed current welding technique. Rolled plates of 10 mm thickness
have been used as the base material for preparing multipass welded joints. Single V butt joint configuration has been prepared
for joining the plates. The filler metal used for joining the plates is AA 5356 (Al-5Mg (wt.%)) grade aluminum alloy. Four
different welding techniques have been used to fabricate the joints and they are: (i) continuous current GTAW (CCGTAW), (ii)
pulsed current GTAW (PCGTAW), (iii) continuous current GMAW (CCGMAW), and (iv) pulsed current GMAW (PCGMAW) processes. Argon
(99.99% pure) has been used as the shielding gas. Rotary bending fatigue testing machine has been used to evaluate fatigue
behavior of the welded joints. Current pulsing leads to relatively finer and more equi-axed grain structure in GTA and GMA
welds. Grain refinement is accompanied by an increase in fatigue life and endurance limit. Simple postweld aging treatment
applied to the joints is found to be beneficial to enhance the fatigue performance of the welded joints. 相似文献
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In the present study, low transformation temperature welding wire (LTTW), which can induce residual compressive stress around 304L welded joints, has been developed to improve the fatigue performance of welded joints. Procedure of design and chemical composition of weld metal and deposited metal of LTTW are introduced. The microstructure of weld metal of LTTW is composed of low carbon martensite and residual austenite. The residual stress distribution of a single welding bead of LTTW was measured and the result shows that compressive residual stress is generated. In addition, fatigue test was also carried out on no-load cruciform welded joints of 304L stainless steel under three conditions: as welded, 308L dressing and LTTW dressing. The result shows that the fatigue life of LTTW dressing joints (2×106 cycles) is improved by 14–23 times and 3–6 times compared with that of as welded joints and 308L dressing joints. 相似文献
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I. N. Shiganov A. A. Kholopov A. V. Trushnikov E. N. Ioda M. D. Panteleev A. A. Skupov 《Welding International》2017,31(6):481-486
The possibilities of using laser welding with a filler wire for joining sheet materials made of V-1469 and V-1461 high-strength aluminium–lithium alloys are investigated. The optimum conditions of placing the filler wire in relation to the laser beam in the weld pool are determined. The optimum welding parameters resulting in the high-quality formation of the welded joint with equal sagging and excess metal and the absence of porosity and cracks are also determined. The mechanical properties of welded joints are outlined and the microstructure of the welded joint is investigated. The corrosion resistance of the produced welded joints is studied. 相似文献
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Titanium alloy lap joints were performed by combined laser welding and resistance seam welding process. The welding characteristics of this combined process were investigated compared with that of laser welding. The experimental results indicate that the combined process welded joint has larger weld width at the lap surface. The joint tensile shear force of combined process is 2.5 times that of laser welding. There are some pores around the lap surface in laser welded joint, and most pores can be eliminated by resistance seam welding process. Metallographic examinations of combined process welded joint reveal that the microstructure in heat-affected zone (HAZ) and weld zone has the acicular martensite morphology, which causes that the microhardness in HAZ and weld zone increases compared with the base metal, and the microhardness in weld zone is highest. 相似文献
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通过分析焊接对喷瓷管道焊接接头处瓷层的影响,提出了用自熔覆法对焊接接头进行防护。试验结果表明,在合适的电流下采用TIG焊打底能够使焊口附近的瓷层重熔并向焊缝流布、熔覆,在焊缝区形成保护层,起到自熔覆防护作用;焊前管端预涂釉浆能有效增加焊后接头区自熔覆瓷层的厚度,提高瓷层的防护效果;焊后采用火焰加热对接头区进行重熔处理,可以消除瓷层中气泡、裂纹等缺陷。采用焊前管端预涂釉浆、TIG焊打底、焊条电弧焊填充、焊后接头区瓷层重熔处理等配套措施能够有效解决喷瓷管道焊接接头的防护问题,焊后不用进行内补口。 相似文献
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采用不同的焊接工艺参数,对GH4169镍基高温合金薄板进行MIG焊接正交试验。通过金相试验,观察镍基高温合金焊接接头的显微组织,可以划分为焊缝中心等轴晶区、焊缝边缘柱状晶区、热影响区和母材组织。利用室温拉伸和显微硬度试验,测定镍基高温合金焊接接头的抗拉强度、断后伸长率与显微硬度等力学性能,并与母材的力学性能进行比较。使用极差分析法,研究焊接电流、电弧电压与焊接速度对接头力学性能的影响规律,并获得了优化的焊接工艺参数。 相似文献