激光填丝焊接超薄不锈钢工艺研究

对0.2 mm厚的1Cr18Ni9Ti奥氏体不锈钢薄板脉冲激光填丝焊相关的工艺参数对焊缝成形质量的影响进行了研究,分析了焊接接头的组织和力学性能,比较了填丝与非填丝两种情况下获得的焊缝成形质量。结果表明:激光填丝焊相对于非填丝焊有更好的焊缝成形质量;抗拉强度较非填丝焊接接头强度提高了3%,可达到母材抗拉强度的99%;在最佳焊接工艺参数下激光填丝焊接接头的显微组织是由焊缝中心区的等轴晶区和焊缝边缘细小的柱状晶区组成;采用激光填丝焊接超薄不锈钢可为解决非填丝焊焊接接头的凹陷问题提供参考。     

SUS301L不锈钢激光-脉冲MAG复合焊接的熔滴过渡及接头组织性能研究

使用激光-脉冲MAG复合焊对SUS301L奥氏体不锈钢平板进行了对接焊试验,研究其焊接过程中电弧形态、熔滴过渡,以及其与脉冲电流、电压的对应关系,并分析了焊后接头的组织与力学性能。结果表明:激光-脉冲MAG复合焊的电弧形态及熔滴过渡稳定,呈一脉一滴平稳过渡。焊缝中心主要为细小的柱状奥氏体晶粒和少量的δ铁素体组织。焊缝中心的硬度最低,母材硬度最高,越接近母材硬度越大。接头的平均抗拉强度为736 MPa,达到母材的76%;所有弯曲试样压弯180°后,表面未出现裂纹。SUS301L奥氏体不锈钢激光-脉冲MAG复合焊接的接头质量较好。     

304不锈钢薄板激光焊搭接接头组织及性能

研究0.8 mm厚度304不锈钢薄板的搭接连续激光焊工艺,分析接头的显微组织和部分力学性能。与电阻缝焊接头进行比较,结果表明:激光焊成形良好,在适当的工艺规范下,激光焊和电阻缝焊的水压试验都可以达到8.0 MPa;激光焊的热影响区更窄并且焊缝中组织为奥氏体;较电阻缝焊焊缝呈更均匀、细小的柱状晶;两种焊接方法的拉伸剪切试验的断裂位置均位于母材。     

超薄不锈钢激光焊接头的微观组织与力学性能

研究了厚度为0.1 mm的321不锈钢薄板的搭接脉冲激光焊工艺,采用正交试验法对焊接工艺进行优化,并对焊接接头的微观组织和力学性能进行了分析测试。结果表明,采用在最优工艺参数——焊接速度0.5 m/min,激光功率150 W,离焦量+2 mm时,焊接接头的剪切载荷最大,达到母材拉伸力的94%,焊缝区的显微硬度值高于母材的;金相组织观察显示,焊缝中心为细小的等轴晶,焊缝边缘为细小的柱状晶;接头剪切断口SEM分析表明,接头呈明显的韧性断裂特征。     

0Cr18Ni9不锈钢脉冲Nd:YAG固体激光焊和TIG焊焊缝耐腐蚀性能对比研究

利用硫酸-硫酸铜溶液对0.6mm厚304不锈钢Nd:YAG固体脉冲激光焊焊接接头耐腐蚀性能进行了试验研究,并与其TIG焊焊接接头及母材的耐腐蚀性能做了对比分析.结果表明,通过腐蚀前后显微组织发现母材没有晶间腐蚀现象,脉冲激光焊焊缝有轻微腐蚀,而TIG焊焊缝在晶界出现了较为明显的晶间腐蚀沟,腐蚀沟沿晶界有网状分布特征.通过腐蚀前后的显微硬度比较发现,脉冲激光焊焊缝最大硬度大于TIG焊焊缝,大于母材,TIG焊焊缝有部分低于母材的硬度区.提出了提高304不锈钢激光焊焊缝耐晶间腐蚀性能的方法和措施.     

321不锈钢薄板激光微焊接接头组织性能研究

本文采用微型脉冲激光实现了0．3mm厚321不锈钢片的对接焊,通过正交优化设计对工艺参数进行了优化,利用光学显微镜,电子精密拉伸机等分析测试手段,研究了工艺参数对焊接接头微观形貌及组织的影响。结果表明,焊接接头获得最大抗拉强度的最优工艺参数是脉;中功率百分比为18、脉冲宽度为4ms、脉冲频率为2Hz,此时焊接接头的承载能力达到母材的98％。分析了功率密度对焊缝成形和力学性能的影响。承载能力较高的焊接接头其显微组织是由焊缝中心区的等轴晶和焊缝边缘粗大的柱状晶组成,并且焊接接头的显微硬度高于母材。     

TiNi形状记忆合金薄片的微激光焊接工艺研究

采用微激光对厚度为0．2mm的TiNi形状记忆合金薄片进行焊接,通过正交试验以获得最大的接头抗拉力为目标对工艺参数进行了优化,并分析了工艺参数对焊接接头表面及横截面形貌的影响。结果表明,焊接接头获得最大抗拉力的最优工艺参数是：脉冲功率百分比21％、脉冲宽度2．3ms、脉冲频率4Hz,此时焊接接头的承载能力达到母材的97％。当微激光焊的功率百分比、脉冲频率、脉冲宽度过大时会产生热量的积累、导致焊缝发生烧穿;过小时激光脉冲的熔透能力较弱、导致焊缝未焊透,这两者是导致焊接接头承载能力较差的主要原因。     

薄片状TiNi合金/不锈钢激光微焊接接头组织特征

采用微型脉冲激光对0.2 mm厚的薄片状TiNi形状记忆合金/不锈钢异种材料进行对接焊,研究了接头的微观组织特征。结果表明,以纯Ni丝为填充材料、以微型脉冲激光为热源可以实现TiNi合金/不锈钢异种材料的良好焊接。焊缝中心区为细小的等轴晶组织,主要元素为Ti、Ni、Fe。Ti元素的含量和不锈钢母材基本接近, Ni元素的含量略高于TiNi合金母材,远高于不锈钢母材,但TiNi合金母材一侧基本没有Fe元素。TiNi合金母材与焊缝之间存在明显的界面区,宽度为10～20 μm,界面区有从不锈钢母材扩散而来的Fe、Cr元素。不锈钢母材与焊缝之间界面区的宽度较小,表现为界面线     

0．2mm厚高强钢激光微焊接接头的组织性能

本文采用精密脉冲激光对厚度为0.2mm的高强钢进行焊接试验,利用光学显微镜、电子精密拉伸机等分析测试手段,研究了焊接工艺参数对接头组织与性能的影响。结果表明,以氩气为保护气体,在功率15W,脉宽1．6ms,脉冲频率6．5Hz的工艺参数下,以激光为热源可成功实现厚度0.2mm的高强钢的对接焊,焊缝成形良好,焊接接头显微组织由焊缝中心区的细小板条状马氏体组成,其接头性能抗拉强度高于母材。     

不锈钢薄板激光焊接工艺研究

针对不锈钢薄板的激光焊接进行了研究,分析了激光工艺参数对超薄不锈钢板焊接质量的影响。结果表明,对于不锈钢薄板激光焊接,脉冲工作电流和脉冲宽度对焊缝成形影响很大。在合适的工艺参数下,超薄不锈钢薄板焊缝成形良好,焊接接头基本与母材等强。     

Ti—55M高温Ti合金焊缝塑性的改善

考察了Ti-55M高温Ti合金焊接接头力学性能,结果显示焊缝在明显的室脆性,探讨了Ti-55M焊缝室温塑性的各种影响因素,尝试使用调整焊缝化学成分的方法改善Ti-55M焊缝的塑性,选择ELI级Ti-5Al-2.5Sn焊丝、配合脉冲氩弧焊工艺和适当的焊后热处理制度、获得的焊缝塑性接近母材的塑性,接头的室温和高温强度以及高温持久等重要性能能够满足母材技术指标要求。     

A NEW METHOD FOR MEASURING LONG-TERM CREEP DEFORMATION IN A SMALL REGION

1.IntroductionManypressurizedcomponentsinpetrol-chemicalplantsandelectricitygeneratingplantsoperateforlongperiodsathightemperaturewherecreepmayoccur.Undercreepconditionstheperformanceofweldsincomponentsmaybealife--limitingfactor.Ahighpercentageofthefailureshavebeenreportedtooccurintheregionsofheterogeneousmicrostructure.Forconventionaluniaxialtensilecreeptestingtheevaluationofcreepdeformationandfractureresistanceisonlyanaverageinformationwithinthegaugelength,whichcannotprovidethefundamentalund…     

Microstructure and Oxidation Characteristics of Laser and GTAW Weldments in Austenitic Stainless Steels

The present investigation reports microstructure and high-temperature oxidation behavior of GTAW and laser weldments of 316L stainless steel. The microstructure and oxidation behavior of composite laser weldment are found to be influenced by the welding speed. In GTAW weldment, weld metal shows higher oxidation rate as compared to base metal of same weldment. Furthermore, the inoculation of Ce in GTAW weld influences the microstructure and oxidation characteristics. The scale morphologies, scale adherence, and spallation have been characterized by SEM and EDAX.     

Oxidation behavior of microstructurally-Different regions in the weldment of 9Cr-1Mo steel

Regions with different microstructures have been identified in the weldments of 9Cr-1 Mo steel. Weldments comprising threthree regions, i.e., weld metal, heat-affected zone (HAZ), and base metal, were oxidized in air at 923 K for different durations up to 500 hr. The crown area of the weld metal was found to form a thicker oxide scale than the other regions of the weldment. When the oxidation kinetics of different regions were compared (by separating out the coupons of the HAZ and the crown and root portions of the weld metal and then oxidizing them), the crown area of the weld was found to oxidize at a much higher rate than the others. Scanning electron microscopy (SEM) was carried out to assess the morphological variations in the different regions of the weldment. The compositional variations in the scales over the different regions have been characterized by the energy-dispersive analyses of X-rays (EDX), and the results thereof have also been corroborated by secondary ion mass spectrometry (SIMS).     

Properties of titanium alloy AT2 and weldments of the alloy

Conclusions Alloy AT2 and weldments of the alloy have high strength and ductility at temperatures from 500 to –253°. The deformability of the weld seam is approximately the same as that of the alloy. The corrosion resistance in hydrochloric and phosphoric acids is the same for the weld seam and the base metal. Alloy AT2 and weldments of the alloy are more resistant to hydrochloric and phosphoric acids than alloy VT1.E. O. Paton Institute of Electric Welding of the Academy of Sciences, Ukrainian SSR. Translated from Metallovedenie i Termicheskaya Obrabotka Metallov, No. 1, pp. 66–68, January, 1976.     

ISOCHRONOUS STRESS-STRAIN CURVES OF LOW ALLOY STEEL CROSS-WELD-SPECIMEN AT HIGH TEMPERATURE

In this work, a parametric approach is presented and utilized to determine the creep properties of weldments; then the model of creep strain for cross weld specimen is given. On the basis of the experimental results, attempt has been made to establish equations of the isochronous stress-strain for weld joint that can predict the function of loading and service time in use of the creep data of base metal and weld metal.     

不同组配P91钢焊接接头断裂性能的试验研究

采用JR阻力曲线试验方法，研究了强度组配对P91钢焊接接头不同区域断裂性能的影响规律，并分析了不同组配P91钢焊接接头的硬度分布。结果表明，焊接热循环对其热影响区的性能没有明显的影响；低组配焊接接头焊缝区的断裂阻力要高于高组配焊接接头焊缝区的断裂阻力，即强度低组配有利于提高P91钢焊缝的抗断性能；对于熔合线区域，试验结果体现出类似的规律，即随组配比的降低，熔合线区域的抗断性能升高；而无论何种强度组配的P91钢焊接接头。其焊缝金属的抗断性能均优于熔合线区域。     

Application of high velocity impact welding at varied different length scales

Three complementary impact welding technologies are described in this paper. They are explosive welding, magnetic pulse welding, and laser impact welding, which have been used to provide metallurgical bonds between both similar and dissimilar metal pairs. They share the physical principle that general impact-driven welding can be carried out by oblique impact but are used at different length scales from meters to sub-millimeter. The different length scales require different kinds of systems to drive the process, and the scales themselves can give different weld morphologies. Metallographic analysis on cross-sections shows a wavy interface morphology which is likely the result of an instability associated with jetting, which scours the surfaces clean during impact. The normalized period and amplitude of the undulations increase with increasing impact energy density. Microhardness testing results show the impact welded interface has a much greater hardness than the base metals. This can lead to weldments that have strengths equal to or greater than that of the weakest base material.     

中国低活马氏体钢熔化焊接头硬度与微观组织

针对4 mm厚的中国低活马氏体钢,采用TIG焊接方法分别对预热和未预热两组试样进行了焊接和焊后回火处理,对焊接接头的硬度和微观组织结构进行了测试和观察.结果表明,焊缝区硬度值偏高,靠近母材的热影响区出现较窄的软化带;焊接接头金相组织为板条特征明显的回火马氏体组织,未预热试样的马氏体含量与预热试样相比较,两者之间没有明显的差异.在晶内和晶界处分布大量的碳化物,焊缝区为尺寸较小的棒状,母材和热影响区为尺寸较大的颗粒状,接头的组织和碳化物的析出对焊接接头的硬度有很大的影响.

Abstract：

The preheated and non-preheated 4 man China low activation martensitic steel (CLAM) plate were welded by TIG welding and post-weld heat treating, and the hardness and micrcstructure in welded joint were tested and observed. The results show that the hardness in the weld metal is higher and the softening band in the heat-affected zone (HAZ) closing to the base metal. The tempered lath martensite is observed in welded joints. There is no significant difference in martensite content between the preheated and non preheated weldments. A large amount of carbide particles are observed in the grains and at the grain boundary. The carbides are small rods in weld metal and large granular in the HAZ and base metal respectively. The mierostrueture and carbides in welded joints have great effect on the hardness.     

Potential-Sonden-Messungen und Potential-Profile über Schweißverbindungen korrosionsbeständiger Nickel-Basis-Werkstoffe und Sonderstähle

Potential probe measurements and potential profiles across weldments of corrosion resistant nickel-base alloys and special stainless steels A great number of potential profiles was measured across weldments (SMAW, GTAM, GMAW, Plasma) of the highly corrosion-resistant nickel-chromium-molybdenum alloys 22, C-276, C-4, of the nickel-chromium-iron-molybdenum-copper alloy G-3 as well as of the highly corrosion-resistant austenitic steel Cronifer 1925 hMo. After several tests had been made in a high-ohmic electrolyte solution of 90 vol.-% of methanol + 10 vol.-% of 10^?3 M HCl ( χ = 18 to 20 μs/cm) the tests were continued, for reasons of easier handling, in deionized water whose conductivity was adjusted by using 0.1 M HCl to χ = 10 to 20 μs/cm. It clearly proved that the potential profiles of various weld joints were dependent on the electrolyte. The potential profiles measured across weldments of the NiCrMo alloys which were made with matching filler metal revealed only insignificant or no differences between the potentials of the base material and the weldment. Consequently, in chloride-containing electrolytes it is very unlikely that matching NiCrMo weldments are subject to a preferred corrosion attack. This corresponds to practical experience. The potential profiles in the aqueous HCl electrolyte across weldments of the 6% Mo stainless steel Cronifer 1925 hMo and of the NiCrFeMoCu alloy G-3 welded with a NiCrMo-filler metal showed a potential drop of up to 420 mV over the weldment when compared with the base material. These potential differences can be explained by means of current density-potential curves, showing the electrochemical reactions of base material and weldment with the electrolyte to be different. Nevertheless, the corrosion resistance of the weldment is not inferior to that of the base material.