焊材冶金特性对不锈钢焊缝金属超低温韧性的影响（上）

介绍了超低温用不锈钢的焊接性,分析了超低温不锈钢焊接材料的冶金特性及影响因素,探讨了超低温不锈铜焊接材料的类型对焊缝金属韧性的影响。结果表明,奥氏体不锈铜的焊接性是很好的,但如果焊接材料选用不合造．或施焊工艺不正确,亦会出现焊缝热裂倾向和焊缝超低温韧性不达标等问题。影响焊接材料冶金特性的主要因素是焊缝组织、化学成分、熔渣性质和工艺参数等,对焊缝超低温冲击能量不利的影响因素主要来自药皮、药粉、焊剂及焊接工艺。焊接材料的类型对不锈钢焊缝金属超低温冲击能量有明显的影响,鸽极氩弧焊焊材的;中击吸收能量最高,焊缝韧性储备最大,其次是气体保护焊焊材,电焊条、药芯焊丝和埋弧焊焊接材料焊缝金属的低温冲击能量也能达标,有的韧性储备还很不错。     

铬镍奥氏体不锈钢的焊接质量问题及对策

分析了铬镍奥氏体不锈钢焊接存在的质量问题，从奥氏体不锈钢接头的耐蚀性、热裂敏感性、接头脆化倾向及奥氏体不锈钢焊缝中的气孔倾向四方面，探讨了铬镍奥氏体不锈钢焊接质量问题产生的原因及影响因素．提出了奥氏体不锈铜焊接质量问题的改进途径。结果表明，提高接头的耐蚀性和抗热裂性能的主要冶金措施是，选用焊缝为超低C、含有少量δ相（3％～5％）、含有稳定化元素Nb的焊接材料。保证奥氏体不锈钢焊接质量的主要工艺措施是．采用焊接能量集中的焊接方法，工艺参数选择应遵循尽可能加快接头冷却的原则．工艺措施应有利降低焊接残余拉应力。为提高接头的抗晶间腐蚀能力．必要时可以采用稳定化退火或固溶处理。防止奥氏体不锈钢焊缝中气孔的根本措施是，限制气体来源和改善熔池中气体逸出条件。     

陶瓷与不锈钢的焊接

用电弧焊方法焊接陶瓷与不锈钢,研究了焊接电流、电弧长度等工艺参数对焊接质量的影响。结果表明,在陶瓷金属复合材料的陶瓷层上焊接不锈钢,焊接加热不仅可以改善复合钢管中陶瓷与金属的结合方式,在焊接区实现的陶瓷与金属的微冶金结合,而且焊接后的陶瓷内衬复合钢管的压－剪强度明显增加,焊缝为柱状枝晶组织,焊接熔合区的陶瓷受焊接热作用由原来的树枝晶改变为细小的等轴晶,陶瓷与母材呈现微冶金结合方式,焊接影响区陶瓷仍保留树枝晶特征。     

不锈钢薄板的氩氢混合气体保护焊

为了解决不锈钢薄件制品的焊接,我厂对厚0.3～0.8mm直径80～600mm的各种规格的薄壁筒体进行焊接试验对比。对比1Cr18Ni9Ti不锈钢的焊接,通常采用的方法有连续直流钨极氩弧焊,低频脉冲钨极氩弧焊、高频脉冲钨极氩弧焊、微束等离子弧焊等。由于奥氏体不锈钢的冶金可焊性良好,所以不锈钢薄板焊接技术的关键是防止烧穿和保证良好的焊缝成形。     

双相不锈钢制冷凝器SAF2507换热管与316L管板的焊接工艺

塔顶冷凝冷却系统是炼油厂腐蚀最严重的部位，寻求新材料代替碳钢、高合金钢等腐蚀比较严重的材料，是工程应用的需求。文章介绍了双相不锈钢焊接的特点，提出了双相不锈钢制冷凝器SAF2507换热管与316L板焊接工艺，采用不同接头形式、不同的焊接保护气体进行了焊接试验，并通过对焊缝及热影响区组织的金相分析，找出了合理的焊接工艺。     

不锈钢管道焊接背面防氧化的方法

通过对不锈钢管道焊接的实践与研究，提出了解决不锈钢管道焊接过程中容易出现的背面氧化问题的几种方法：不锈钢管道焊接内侧充氩保护，不锈钢管道背面氩弧焊打底自保护，不锈钢管道充氮背面保护以及超低碳不锈钢管根部充氩防焊缝根部背面氧化保护。     

不锈钢船用焊接技术及焊接材料

介绍了我国造船业的发展及对焊接材料的需求，重点讨论了液化天然气（LGN）船及双相不锈钢化学品毒的焊接技术。对于液化天然气设施，焊逢金属中铁素体含量是影响-196℃超低温韧性的主要因素，可以通过调整Creq、Nieq来控制焊缝中的铁素体含量。对于双相不锈钢化学品船焊缝和焊接HAZ，只有保证足够的奥氏体数量（铁素体在5％-40％），才能得到满意的力学性能与耐腐蚀性能。     

浅谈不锈钢管道氩弧焊的焊缝背面保护方法

在石油化工装置中，往往有大量的不锈钢管道（含炉管）需要现场焊接。为了保证焊接质量和内部清洁度，通常采用氩弧焊打底的焊接方法。本文详细介绍了不锈钢氩弧焊时，几种常用的焊缝背面保护方法。     

TP316L+Q235不锈钢复合钢板的焊接工艺探讨

不锈钢复合钢板的焊接要求较高，特别是保证焊缝的耐腐蚀性是关键。本文主要对TP316L＋Q235不锈钢复合钢板的对接和角接形式的接头，从焊前准备工作，焊接方法及焊接材料的选择进行分析，制定出较合理的焊接工艺方案，满足了设计施工的需要。     

铜-不锈钢套管式结构件的焊接

如图1所示的铜一不锈钢套管式构件图样要求采用熔化焊接组焊，而内管与外管不锈钢及法兰盘铜合金之间虽然具有焊接性，但此类结构的焊接的确十分少见。因内、外管材质不同，其热导率、比热容等参数相差悬殊，对焊接工序及焊接工艺都提出了较高的要求。为此我们做了工艺模拟试验，焊接排序为①②③④。第一次试验发现在第④道焊缝焊完后，在①、④焊缝中均产生了极为严重的裂纹。     

节镍型奥氏体不锈钢的高温塑性

采用Gleeble-3800型热/力模拟试验机对不同铜含量的节镍型奥氏体不锈钢进行了高温拉伸试验,分析了拉伸断口附近显微组织,并对其高温塑性进行了研究。结果表明:奥氏体不锈钢在1 150～1 250℃具有较好的高温塑性;随着铜含量的增加高温塑性下降;铁素体含量及形状对其高温塑性影响较大,铁素体含量的增多和网状分布会使其高温塑性显著下降。     

不锈钢的焊接性能与工艺措施

不锈钢得到越来越广泛应用的同时对其焊接性能也提出越来越高的要求.分析并介绍了各种不锈钢的焊接性能与工艺措施.     

反应堆压力容器不锈钢焊接中铁素体的控制

对不锈钢焊缝的凝固模式以及铁素体对焊缝质量的影响进行分析,结果表明不锈钢焊缝中的铁素体含量决定了焊缝的凝固模式。当铁素体数FN在5~20之间时,可以防止凝固裂纹沿晶粒边界的扩展。由此提出控制不锈钢焊材化学成分的方法,可避免或减少不锈钢凝固裂纹的产生。经过对多种铁素体测量方法的综合分析,建议采用化学计算和磁性测定相结合的方法进行测定。     

不锈钢在压力容器中的应用及焊接技术(一)

通过对我国20世纪尿素不锈钢的焊接、腐蚀性能的研究及大型尿素设备、双相钢设备和高级不锈钢设备及管道的制造与焊接技术的回顾，介绍不锈钢在一些典型压力容器中的应用并展望其扩大应用的前景。     

粉末冶金工艺制备不锈钢的研究进展

制备不锈钢的粉末冶金工艺与传统熔炼工艺相比具有成本低的优势,其生产的零件接近净成形且尺寸精度较高。主要介绍了近年来国内外利用粉末冶金工艺制备不锈钢的研究进展,包括烧结理论、成形和烧结技术的发展及成分添加剂对不锈钢组织和性能的改善。最后结合粉末冶金不锈钢的应用现状,提出了今后研究应重点关注的方向。     

Subsurface damage development during fretting fatigue of high strength steel

The results of fretting fatigue experiments performed on two high-strength structural steels, PH 13-8 Mo stainless steel and quenched and tempered 4340 steel, are evaluated. Observations regarding the subsurface deformation and cracking behavior of the steels are compared and contrasted. It was found that the fretting stresses influenced early crack growth to a greater depth in PH 13-8 Mo stainless steel than in 4340 steel. In addition, experiments on PH 13-8 Mo led to the development of a region below the fretting scar that underwent a microstructural transformation, while experiments on 4340 steel did not. Likely reasons for this discrepancy are suggested. Differences in the formation of oxide layers and the occurrence of adhesion between the two materials are also discussed.     

Improving the wear life of a cocoa spray‐drying unit

In the chocolate production process, the moisture content of ground cocoa is removed in a spray‐drying unit, in which wet cocoa is pumped through a high‐pressure pump. Wear occurs in this high‐pressure pump, which can cause problems in the system. Originally, valves and beds were made of AISI 316 Ti austenitic stainless steel, and their average wear life was less than 280 h, obviously too short for use in industrial production. The aim of the research reported in this paper was to investigate ways to increase the wear life of these parts. In this respect six different materials were tested. Valves and beds were produced from four different steels and two powder metals. The steel parts were hardened by heat treatment. All the parts were electroplated with CrN or TiN. Wear life tests were carried out, and it was shown that AISI M2 high‐speed steel valves and beds gave the longest wear lives.     

Nondestructive evaluation of a crack on austenitic stainless steel using a sheet type induced current and a Hall sensor array

Austenitic stainless steels (hereafter A-STS) such as STS304 and STS316 are paramagnetic metals. However, a small amount of partial magnetization is generated in A-STS because of the imperfect final heat treatment and mechanical processing. Surface cracks on paramagnetic metal with a partially magnetized region (hereafter PMR) are difficult to inspect. In this paper, we propose a method for high speed inspection and evaluation of a crack on A-STS. Cracks can be inspected with high speed by using 64 arrayed Hall sensors (HSA) with 3.5 mm spatial resolution and a sheet type induced current (STIC). Then, a crack can be evaluated quantitatively by using the detailed distribution of the magnetic field obtained by using single Hall sensor scanning (SSS) around the inspected crack area. Several cracks on A-STS with partially magnetized areas were examined and the experimental formulas were derived.     

奥氏体不锈钢中铁素体含量计算

介绍了奥氏体不锈钢中铁素体的作用和测量方法 ,分析了奥氏体不锈钢中铁素体形成机理 ,重点阐述了采用不锈钢组织图和合金元素铬当量与镍当量控制奥氏体不锈钢中铁素体含量的计算方法     

Galling resistance evaluation of tool steels by two different laboratory test methods for sheet metal forming

Adhesive accumulation of work material on the tool surface is today a major problem in many sheet metal‐forming applications. Different laboratory test methods are used to investigate galling with respect to different tool materials, lubricants and process conditions. In the present study, the galling resistance of a modern nitrogen‐alloyed powder metallurgy tool steel and an conventional ingot cast D2 type tool steel was evaluated under lubricated sliding against ferritic stainless steel sheets using a commercial pin‐on‐disc (POD) and an in‐house made slider‐on‐flat‐surface (SOFS) tribotester. The investigated tool steels ranked similarly in terms of galling resistanc in both test methods. However, sliding distances to galling were longer for the SOFS equipment due to continuous sliding on new lubricated sheet surface. Best performance was demonstrated by the powder metallurgy tool steel treated to 65 HRC. Differences in friction behaviour and galling initiation were analysed on the basis of the two different working conditions, i.e. open (SOFS) and closed (POD) tribosystems. Copyright © 2012 John Wiley & Sons, Ltd.