Untersuchung zur Gefügestabilität und Korrosionsbeständigkeit von Nickelbasislegierungen unter fertigungsüblichen Schweißbedingungen am Beispiel der Werkstofftypen NiMo28 und NiMo16Cr16Ti

Structure examinations and corrosion sensitiveness of welded nickel alloys NiMo28 and NiMo16Cr16Ti The sensitivity of NiMo 28 (Hastelloy B-2) and NiMo 16Cr 16Ti (Hastelloy C-4) to intercrystalline corrosion in the heat-affected zone of welded joints was investigated. The temperature-cycles in welded joints typically used in the construction of chemical equipment were experimentally determined. The effect of thermal stress on both the structural stability and corrosion sensitivity was then determined by metallographic examination. The results showed Hastelloy C-4 to have a distinctly improved structural stability over the previously available Hastelloy C-276. Under the test conditions we employed no negative effect on corrosion sensitivity in the area of the heat-affected zone of the welded joint is to be expected. Hastelloy B-2 shows – dependent on heat input – more or less significant structural changes of the grain boundary, the existence of droplet-like heterogenicity suggests the possibility of intergranular corrosion.     

Characterization of microstructure,mechanical properties and corrosion resistance of dissimilar welded joint between 2205 duplex stainless steel and 16MnR

The joint of dissimilar metals between 2205 duplex stainless steel and 16MnR low alloy high strength steel are welded by tungsten inert gas arc welding (GTAW) and shielded metal arc welding (SMAW) respectively. The microstructures of welded joints are investigated using scanning electron microscope, optical microscope and transmission electron microscopy respectively. The relationship between mechanical properties, corrosion resistance and microstructure of welded joints is evaluated. Results indicate that there are a decarburized layer and an unmixed zone close to the fusion line. It is also indicated that, austenite and acicular ferrite structures distribute uniformly in the weld metal, which is advantageous for better toughness and ductility of joints. Mechanical properties of joints welded by the two kinds of welding technology are satisfied. However, the corrosion resistance of the weldment produced by GTAW is superior to that by SMAW in chloride solution. Based on the present work, it is concluded that GTAW is the suitable welding procedure for joining dissimilar metals between 2205 duplex stainless steel and 16MnR.     

16MnR钢激光冲击工艺及对焊接结构应力腐蚀性能的影响EI北大核心CSCD

对16MnR母材进行激光冲击工艺实验,获得优化的激光冲击工艺参数。对激光-MAG复合焊焊接接头进行表面处理,分析接头激光冲击前后状态的残余应力分布及抗应力腐蚀性能变化。结果表明:对16MnR钢平板经激光冲击处理后,在材料表面最大可引入475μm厚度的塑性变形层,并同时引入-593 MPa的压应力分布。采用优化激光冲击工艺对16MnR钢焊接接头进行表面处理后,可有效减小焊接接头表面的残余拉应力分布。在3.5%NaCl(质量分数)条件下对激光冲击处理前后的接头试样进行慢应变速率应力腐蚀实验,发现激光冲击处理前后16MnR钢焊接接头的应力腐蚀敏感指数I_(SSRT)分别为0.106和0.104,表明激光冲击可以提高接头的抗应力腐蚀能力。     

2195铝锂合金搅拌摩擦焊接头盐雾腐蚀行为研究

本文研究了厚度为8 mm的2195铝锂合金母材及搅拌摩擦焊接头在3.5wt.％NaCl介质中的盐雾腐蚀行为,计算了不同腐蚀周期下的腐蚀速率,并通过OM、SEM、TEM观察分析母材与焊核区的腐蚀微观形貌.结果 表明:2195铝锂合金母材及搅拌摩擦焊接头在3.5％ NaCl腐蚀介质中的主要腐蚀形式为点蚀,随时间的延长发展为...     

船用吊杆0Cr16Ni5Mo不锈钢的焊接

概述了与0Cr16Ni5Mo马氏体不锈钢配套的焊接材料、焊后热处理制度以及适用的焊接工艺。试验选定采用M831A焊条,双U型坡口双面对称焊,焊后进行950℃/2h油淬+500℃/10h回火,得到的焊接接头性能完全达到指标要求。     

Entwicklungstendenzen bei korrosionsbeständigen hochwarmfesten Werkstoffen und ihre schweißtechnische Verarbeitung

Trends of corrosion resistant high-temperature resistant materials and their welding processing High-temperature resistant materials and their joints have to show sufficient mechanical characteristics and good corrosion resistance at temperatures above 500°C during a longer period. This applies also to the Ni-Fe-Cr-alloy Nicrofer 3718 – alloy 330 (material No. 1.4864) which is used primarily in furnace building in connection with the filler metal Thermanit Nicro 82 (material No. 2.4806). Occurring damages on such welded joints show that it is insufficient to determine the seam characteristics only immediately after welding. Rather it is necessary to consider the later processing and operating conditions of the component and to simulate them in an appropriate way at the welding seams during the investigations.     

Investigation of the strength and cyclic fracture toughness of BT-16 titanium alloy subjected to thermal cycling simulating diffusion welding

The effect of the thermal cycle of diffusion welding on the service characteristics of BT-16 titanium alloy are considered. Using standard test equipment the mechanical properties of the alloy after thermal cycling to 860 or 960°C were studied at test temperatures of 960, 860, 300 and 20°C and the fatigue strength and fracture toughness were studied at room temperature.

It was shown that although specimens welded at 960°C displayed superior plastic properties, these were only partially effective in arresting propagating cracks. A greater fatigue crack resistance was seen with material welded at 860°C and it is this temperature which is recommended for diffusion bonding BT-16 titanium alloy components.     

Simulationsuntersuchungen der Wärmeeinflußzonen von Schweißverbindungen der Legierung Hastelloy B-2

Simulated Heat-Affected Zone Studies of Hastelloy B-2 Gleeble studies show that as-welded HAZ corrosion resistance of a low carbon nickel-molybdenum alloy can be preserved by using gasshielded-arc or covered electrode welding. A heat-affected zone study was conducted on a low carbon, nickel-molybdenum, corrosion resistant alloy, commercially known as Hastelloy alloy B-2. Six different production heats were thermally cycled with the Gleeble apparatus to 1300 °C (2372 °F) under several conditions to simulate the heat-affected zones produced by a number of different welding processes. Specimens were subsequently tested in boiling 10% HCl and in 20% HCl at 150 °C (302 °F) in an autoclave. Most of the corrosion penetration measurements were found to be less than the maximum allowable limits, reaffirming that the as-welded heat-affected zone corrosion resistance of alloy B-2 can be preserved when welding is accomplished with the recommended shielded metal rec, gas tungsten arc, and gas metal arc processes.     

Susceptibility of 7050-T7451 electron beam welded specimens to stress corrosion

Susceptibility to stress corrosion tests were carried out on electron beam welded specimens made from 7050-T7451 aluminium alloy. As a comparison, specimens made from base material were tested too. The resistance of the welded material was high: the tensile properties were only slightly lower than those of the base material. After 30 day exposure to a corrosive environment (alternate immersion in a 3.5% NaCl solution), the tensile properties of the welded material were considerably reduced, while the same properties were only slightly affected in the base material. The combined effect of stress and corrosion was only slightly detrimental for the base material and very detrimental for the welded material. At the lowest stress level tested, about 25% of the ultimate stress, the welded specimens failed after a mean life of 90 days. Considerable residual stresses associated with the welding process were measured in a plate. A test was performed to verify the possibility of stress corrosion cracking promoted by the welding residual stresses. In actual fact, no cracks were observed, but the corrosion rate increased, particularly in the areas affected by the higher residual stresses.     

含钪铝合金焊接接头的耐腐蚀性能研究

采用铸锭冶金法制备了含钪Al-Mg合金。用手工氩弧焊焊接方法制备含钪Al-Mg合金焊接接头试样。研究了高镁Al-Mg合金中添加微量稀土元素钪后合金焊接接头的耐盐雾腐蚀和剥落腐蚀性能,用金相显微镜和透射电子显微镜观察了合金焊接接头的显微组织,并探讨了其腐蚀机理。研究结果表明,添加微量稀土元素钪能有效细化合金晶粒,显著提高Al-Mg合金焊接接头的耐腐蚀性能。其耐蚀性机理是合金焊接接头组织中均匀弥散分布着β(Mg5Al8、Mg2Al3)沉淀相,未在晶界上出现β相形成的连续网膜,因此合金焊接接头耐腐蚀性能优良。     

Microstructure and abrasive wear behaviour of iron base hardfacing

Abstract

The influence of the composition and heat treatment of overlays on the abrasive wear resistance of iron base hardfacing alloy overlays is reported. Overlays were deposited using a shielded metal arc (SMA) welding process on structural steel using two commercial hardfacing electrodes, i.e.Fe – 6%Cr – 0.7%C (H₁) and Fe – 32%Cr – 4.5%C (H₂). Abrasive wear resistance of overlays in as welded and heat treated conditions was tested using a pin on disc system against a 300 grade waterproof SiC polishing paper at different normal loads (1 – 4 N) and constant sliding speed 2.0 m s^-1. Optical microscopy was used to study the microstructure of overlays in as welded and heat treated conditions. SEM studies of wear surfaces were carried out to analyse wear mechanisms. It was found that the wear resistance of the high Cr – C coating is better than the low Cr – C hardfacing under identical conditions. Significant variation in hardness was noticed across the interface, indicating the effect of dilution. Hardness of the coating adjacent to the interface was found to be comparatively lower than the coating further away from the interface. Post-weld heat treatment enhanced the abrasive wear resistance.     

Investigation of wear resistance and microstructure of a newly developed chromium and vanadium containing iron‐based hardfacing alloy

Plasma transferred arc (PTA) welded Ni and Co‐based alloys have gained high acceptance in many industrial applications for the wear protection of components. Recently, the cost of nickel and cobalt is rising drastically. This paper presents the development of a cost‐effective high chromium and vanadium containing iron‐based hardfacing alloy with high hardness and wear resistance. The welding processing of the alloy is carried out by PTA welding of atomized powders. Investigations on powder production as well as on weldability are presented. The coatings are metallographically studied by optical microscopy, SEM, EDX and micro‐hardness measurements. The wear resistance properties of the coatings are examined using pin on disk, dry sand rubber wheel and Miller testing, the corrosion properties are determined by immersion corrosion tests. The newly developed iron‐based alloy has nearly the same wear resistance as Ni‐based alloys with fused tungsten carbides at a higher level of corrosion resistance and much lower cost.     

Mikrostruktur und mechanische Eigenschaften der reibgeschweißten γ‐TiAl‐Feingusslegierung Ti‐47Al‐3.5(Mn+Cr+Nb)‐0.8(B+Si)

Microstructure and mechanical properties of friction welded γ‐TiAl based alloy Ti‐47Al‐3.5(Mn+Cr+Nb)‐0.8(B+Si) in investment cast condition. This paper describes properties of joints produced by friction welding of the intermetallic γ‐TiAl based alloy Ti‐47Al‐3.5(Mn+Cr+Nb)‐0.8(B+Si) in investment cast and hot‐isostatically pressed condition. The effect of friction welding parameters on microstructure and local properties are examined and discussed. It is found that the properties of the joint are essentially affected by properties of as‐cast Ti‐47Al‐3.5(Mn+Cr+Nb)‐0.8(B+Si) base material, both at room temperature and 700 °C.     

高阻尼锰铜合金/40CrNiMoA异种材料焊接工艺研究

介绍了高阻尼锰铜合金GZ50与齿轮钢40CrNiMoA异种材料TIG焊接工艺,并对焊接接头拉伸、冲击、冷弯、疲劳性能和接头金相组织、冲击断口、显微硬度以及接头耐海洋大气腐蚀性能等进行了分析.结果表明,采用合理的焊接工艺参数和焊后消应力处理,保证了焊接接头各项性能指标满足要求,焊缝金相组织均匀,断口为韧性断裂;GZ50合金侧和40CrNiMoA钢侧的热影响区宽度基本相同,GZ50合金侧的热影响区与基体组织由于热作用的不同,各相形态与比例不同;焊接接头在海洋大气环境中,12个月的腐蚀速率比6个月的腐蚀速率约低1/2.     

热输入对Q1100钢焊接接头低温韧性及耐蚀性能的影响

采用10 kJ/cm和15 kJ/cm两种焊接热输入对Q1100超高强钢进行熔化极气体保护焊,研究焊接接头的组织性能及局部腐蚀行为。结果表明：两种热输入焊接接头的焊缝组织主要为针状铁素体和少量的粒状贝氏体,粗晶区组织均为板条贝氏体,细晶区组织均为板条贝氏体和粒状贝氏体,临界相变区组织为多边形铁素体、马奥岛和碳化物的混合组织。两种热输入焊接接头中电荷转移电阻均为母材>热影响区>焊缝区,母材耐蚀性最好,热影响区次之,焊缝区耐蚀性最差。在腐蚀过程中,焊缝区作为阳极最先被腐蚀,当腐蚀一定时间后,腐蚀位置发生改变,阳极腐蚀区域转移到母材区,而焊缝区作为阴极得到保护。热输入为10 kJ/cm时,焊接接头具有更好的低温韧性和耐蚀性,其焊缝和热影响区-40℃冲击功分别为46.5 J和30.2 J。     

Characterization of microstructure,chemical composition,corrosion resistance and toughness of a multipass weld joint of superduplex stainless steel UNS S32750

The superduplex stainless steels have an austeno-ferritic microstructure with an average fraction of each phase of approximately 50%. This duplex microstructure improves simultaneously the mechanical properties and corrosion resistance. Welding of these steels is often a critical operation. In this paper we focus on characterization and analysis of a multipass weld joint of UNS S32750 steel prepared using welding conditions equal to industrial standards. The toughness and corrosion resistance properties of the base metal, root pass welded with gas tungsten arc welding, as well as the filler passes, welded with shielded metal arc welding, were evaluated. The microstructure and chemical composition of the selected areas were also determined and correlated to the corrosion and mechanical properties. The root pass was welded with low nickel filler metal and, as a consequence, presented low austenite content and significant precipitation. This precipitation is reflected in the corrosion and mechanical properties. The filler passes presented an adequate ferrite:austenite proportion but, due to their high oxygen content, the toughness was lower than that of the root pass. Corrosion properties were evaluated by cyclic polarization tests in 3.5% NaCl and H₂SO₄ media.     

固溶处理对304/Q245R焊接接头组织及性能的影响

为研究固溶处理对304奥氏体不锈钢和Q245R碳钢异种金属焊接接头显微组织及性能的影响,采用E309-16奥氏体不锈钢焊丝对6 mm厚的304/Q245R板材进行手工电弧焊,焊后使用箱式电阻炉对焊接接头进行固溶处理,对焊接接头进行显微组织观察和力学性能测试.结果表明:相对于固溶处理前,固溶处理后的接头焊缝组织为灰色奥氏体和黑色铁素体,枝晶偏析程度明显降低,Cr、Ni等合金元素分布较为均匀;焊缝和碳钢侧热影响区硬度值均有所提高,最高硬度值为304.59 HV,出现在焊缝位置;接头抗拉强度较高,达570 MPa,拉伸断裂发生在母材Q245R碳钢部位.另外,对焊缝进行XRD测定,未检测到不利于接头性能的相,这表明固溶处理后的异种金属接头性能良好,能够满足工程中的实际需求.     

Precipitation of NiMo in a Ni-Mo base alloy

A study, using electron microscopy and diffraction techniques, was made to characterize a minor second phase present in a corrosion resistant Ni-Mo base alloy (Hastelloy alloy B containing 27.8 wt% Mo and less than 0.002 wt% C. The effect of second phase distribution in the microstructure on tensile properties and corrosion resistance was determined. The only second phase that could be identified by electron diffraction was found to be the intermetallic NiMo phase. It was found that during aging of previously solution treated material, selected grain boundary segments migrate and leave behind NiMo particles. This grain boundary reaction was found to have no detrimental effect on ductility and corrosion resistance.     

地质钻杆摩擦焊接组织和力学性能

探讨了地质钻杆用DZ60钢钻杆管体与40Cr钢钻杆接头的摩擦焊接性，并与采用热墩粗工艺生产的钻杆管体力学性能进行了对比。结果表明，摩擦焊接的地质钻杆具有良好的综合力学性能。     

锂电池PACK包Al-Zn-Mg-Cu铝合金CMT 焊接组织与性能研究

以锂电池包箱体常用的7003铝合金为研究对象,采用冷金属过渡焊接工艺(CMT)对7003铝合金进行焊接后,经过固溶(485 ℃,3 h)、人工时效(160 ℃,2 h)和自然时效(72 h)热处理后,进行组织和性能研究。通过慢应变速率拉伸试验、常温拉伸试验、显微维氏硬度测试、扫描电子显微镜分析等方法,对该铝合金接头的母材和焊缝的抗腐蚀性能、力学性能以及微观组织形貌进行研究。结果表明:当慢应变速率为1×10-6 s-1时,基材和焊接试样的应力腐蚀敏感性指数(ISSRT)分别为2.73%和9.74%;对焊接试样的接头进行晶间腐蚀和剥落腐蚀测试并评级,晶间腐蚀为4级,剥落腐蚀为PA级;焊接接头的电导率、抗拉强度、延伸率分别为22.0%(IACS)、330.7 MPa、10.0%。