铁素体不锈钢焊接的研究和发展现状

主要综述了国内外铁素体不锈钢焊接的研究和发展现状,焊接热过程会导致铁素体不锈钢接头焊缝和HAZ晶粒严重长大,从而造成接头塑韧性和耐蚀性能下降。激光焊、复合热源焊接、脉冲电弧焊、搅拌摩擦焊等新型焊接方法被用来焊接铁素体不锈钢以获得性能更好的接头。并且可以通过控制热输入、提高冷却速度、添加稳定元素、电磁搅拌或超声振动来细化晶粒,提高接头性能。近年来,模拟计算也被用到铁素体不锈钢焊接的研究当中。     

T形焊接接头相控阵超声检测方法研究

T形焊接接头广泛存在于特种设备、海洋平台和建筑结构中,对其进行可靠的检测是设备正常工作的重要保障,相控阵超声检测技术由于其检测灵活可靠,可以用于T形焊接接头的检测.根据实际检测需求,对中厚板T形焊接接头的检测方法和工艺进行研究.首先设计制作模拟缺陷试块;然后设计检测工艺,分别从翼板正面、腹板侧进行扇形扫描,并从翼板背面...     

高速列车不锈钢薄板CMT搭接焊工艺研究

为解决高速列车不锈钢薄板搭接MAG密封焊接出现的变形大、过热严重、焊接缺陷多等问题,采用了冷金属过渡CMT焊接代替MAG焊接,并对焊接工艺进行研究。用CMT搭接焊接厚度0.6 mm与1.5 mm的SUS301L奥氏体不锈钢薄板,采用正交试验法确定合适的工艺参数,并对不同组配间隙进行形貌分析。结果表明,装配间隙为0 mm,焊接速度为2000 mm/min,送丝速度为6 m/min时,可得到良好的焊缝成形。     

焊接方法对双相不锈钢焊接接头耐蚀性的影响

采用气体保护钨极氩弧焊(GTAW)、焊条电弧焊(SMAW)和埋弧焊(SAW)对2205双相不锈钢进行焊接,采用光学显微镜对接头组织进行观察,采用数点法计算铁素体相的含量,测定接头的耐点蚀和耐CO2应力腐蚀性能,研究焊接方法对接头耐蚀性的影响。结果表明,焊接方法影响焊缝组织形态及铁素体含量。GTAW焊缝由不规则的条状组织和两相交织分布的块状组织组成,而SMAW和SAW焊缝为方位不一的条状组织和少量的块状组织。GTAW和SMAW焊缝的铁素体含量为35%~55%,而SAW的不足20%。接头的耐蚀性与铁素体相比例密切相关,GTAW、SMAW和SAW的耐蚀性依次降低。从铁素体相比例和耐蚀性角度考虑,GTAW和SMAW能够获得满意的焊接接头。     

不锈钢芯板结构T形柱轴压性能有限元分析

为探究不锈钢芯板结构作为柱或梁的可行性,研究肢长、面板厚度和芯管壁厚对不锈钢芯板T形柱在轴压作用下稳定性的影响,结合已经完成的不锈钢芯板结构侧压试验,通过有限元计算软件ABAQUS对不锈钢芯板T形柱的轴压性能进行特征值屈曲分析和非线性屈曲分析。研究表明:T形柱的屈曲模式表现为面板局部屈曲;肢长对稳定承载力有很大影响;随着面板厚度的增大,芯管对面板的约束越来越弱,对其稳定承载力的贡献越来越小;芯管能给面板提供支撑,但芯管壁厚到达一定程度后,厚度的增加对稳定承载力的提升作用不大。     

不锈钢T形件螺栓连接承载性能分析与计算方法

为分析不锈钢T形件螺栓连接的静力承载性能,建立了能够准确考虑不锈钢材料力学性能、接触关系和撬力作用的有限元模型,对其进行数值分析,得出了主要参数对T形件连接静力承载性能影响规律:随着翼缘厚度的增加,T形件破坏模式由翼缘完全屈服(模式1)逐渐变为螺栓断裂(模式3);螺栓孔到腹板边缘距离的增大及翼缘材料名义屈服强度的降低仅会降低属于破坏模式1和翼缘屈服同时螺栓断裂(模式2)的T形件的承载力;螺栓直径的增大会提高T形件的承载力。考虑不锈钢材料的应变硬化能力,对翼缘板塑性弯矩进行修正,提出了不锈钢T形件螺栓连接的承载力建议计算方法。     

铁路货车制动用复合管管接头TIG焊应用

本文通过对不锈钢冶金复合管管接头的TIG、MAG焊接工艺进行焊接试验,对比分析焊缝外观、内部渗透探伤、宏观金相后,得出钨极氩弧焊相对气体保护焊更加适宜制动管件焊接的结论,并通过实际生产情况总结出较合理的TIG焊焊接质量控制措施。     

循环荷载作用下不锈钢T形件螺栓连接滞回性能试验研究

为研究不锈钢T形件螺栓连接的滞回性能,分别参照JGJ/T 101—2015《建筑抗震试验规程》和FEMA 461设计了两种不同的循环加载制度,开展16个不锈钢(奥氏体型S30408、双相型S22253)T形件和4个普通钢(Q345B)T形件螺栓连接试件的低周循环加载试验,获得了T形件的滞回曲线和破坏形态,得到了T形件在循环荷载作用下的循环硬化、强度退化特性和耗能能力。研究结果表明：不锈钢T形件的滞回性能明显优于普通钢T形件的,前者耗能平均为后者的2.07倍;循环荷载作用下T形件的破坏形态主要包括螺栓断裂和翼缘板靠近焊趾处断裂两类,与T形件的单调加载破坏模式和加载制度有关;两种牌号不锈钢T形件在循环荷载作用下均表现出较为明显的循环硬化特性,试验后期则由于裂纹的萌生和发展呈现出强度退化;相对于FEMA 461的加载制度,采用JGJ/T 101—2015的循环加载制度得到的T形件的加载圈数和总耗能能力均较大。     

铁素体不锈钢冷弯型材腹板压屈研究

冷弯不锈钢构件耐腐蚀性高、抗力与质量的比率较高,因而被广泛使用,但其对弯曲十分敏感,易发生腹板压屈(横向集中荷载引起的腹板局部屈曲)等现象,必须加以考虑。另一方面,出现了镍含量很低的铁素体不锈钢,与奥氏体不锈钢和双相不锈钢相比,铁素体不锈钢更便宜,而且价格相对比较稳定。下一步将提出有效的设计准则,由此基于数值模拟给出腹板压屈抗力的统一表达式,并利用试验结果对其进行验证。     

Experimental investigation on ferritic stainless steel columns in fire

This paper presents the performance of EN 1.4003 ferritic stainless steel hollow section columns when exposed to fire loading. Experimental analysis of the behaviour of ferritic stainless steel structural members in fire represents a novelty. In detail, three column tests were carried out in the framework of the Research Fund of Coal and Steel (RFCS) project named Structural Applications of Ferritic Stainless Steels (SAFSS, RFSR-CT-2010-00026). Tubular thin-walled members were considered in this study because structural applications of ferritic stainless steels generally incorporate such profiles. Three columns were tested: two square hollow sections (SHS) and a rectangular hollow section (RHS) of different length. Fire loading was applied under a constant concentrically compressive load. Identical column tests at room temperature are also reported.     

Study of web crippling in ferritic stainless steel cold formed sections

Cold-formed stainless steel members are widely used due to their high corrosion resistance and high resistance-to-weight ratio but their susceptibility to buckle implies that instability phenomena such as web crippling, where the web locally buckles due to concentrated transverse forces, must be considered. On the other hand, the emergent ferritic stainless steel has very low nickel content and therefore, they are cheaper and relatively price stable compared to austenitics and duplex. Their promising future has aimed to develop efficient design guidance and as a result, a new unified web crippling resistance expression based on numerical simulations and thereafter validated with experimental results has been proposed.     

Lap shear tests of bolted and screwed ferritic stainless steel connections

The development of design guidance for stainless steel structures requires more tests on ferritic grade connections. This paper deals with a series of lap shear tests which have been carried out on various configurations of bolted and screwed connections. The tests demonstrate net section failure, bearing failure and block tearing failure. The material is a ferritic stainless steel of grade 1.4509 (AISI 441) with a thickness of 0.5–4.5 mm. The results are utilized in developing design guidance in accordance with Eurocodes.     

铁素体不锈钢薄壁水管应用技术浅析

叙述了铁素体不锈钢的种类及特点,就符合生产应用技术要求的铁素体不锈钢钢种及其耐蚀性进行了研究,并对铁素体不锈钢薄壁水管的焊接与连接技术作了简要论述,指出铁素体不锈钢薄壁水管在给排水领域具有良好的应用前景。     

不锈钢等离子切割工艺技术发展

等离子切割可切割材料多、应用领域广,是国内外普遍关注和研究的主流热切割技术,是切割不锈钢最重要的工艺方法;文中主要叙述等离子切割技术发展过程,总结了等离子切割质量与工艺参数的关系,采集了几种典型厚度不锈钢主要切割工艺参数。     

Strengthening of ferritic stainless steel tubular structural members using FRP subjected to Two-Flange-Loading

Cold-formed stainless steel tubular structural members which may experience web crippling failure due to localise concentrated loads or reactions are investigated. A series of tests on fibre-reinforced polymer (FRP) strengthening of cold-formed stainless steel tubular structural members subjected to End-Two-Flange and Interior-Two-Flange loading conditions is presented. The strengthening only applied to a localise area of the members under concentrated load. A total of 58 web crippling tests were conducted. The investigation mainly focused on the effects of different surface treatment, different adhesive, and FRP for strengthening of stainless steel tubular sections against web crippling. The behaviour of stainless steel members strengthened by different widths of FRP plate against web crippling has been also investigated in this study. The test specimens consisted of ferritic stainless steel EN 1.4003 square and rectangular hollow sections. Two different surface treatments were considered. Furthermore, six different adhesives and six different FRPs were also considered in this study. The properties of adhesive and FRP as well as the bonding between the FRP and stainless steel tube have significant influence on the effectiveness of the strengthening. Most of the strengthened specimens were failed by debonding of FRP plates form the stainless steel tubes. Six different failure modes were observed in the tests, namely the adhesion, cohesion, combination of adhesion and cohesion, interlaminar failure of FRP plate, FRP delaminating failure and web crippling failure. The failure loads, failure modes, and the load-web deformation behaviour of the ferritic stainless steel sections are presented in this study. It was found that the web crippling capacity of ferritic stainless steel tubular sections may increase up to 51% using FRP strengthening.     

塔式起重机钢结构焊接工艺探讨

根据塔式起重机钢结构特点,分析了塔式起重机钢结构件的焊接质量及其影响因素,介绍了自动焊接机和焊接变位机用于标准节焊接制造的优势,可很好地满足焊接质量及外观要求。     

Experimental study on mechanical behavior of an impacted steel tubular T-joint in fire

Blast and fire usually take place together on offshore oil and gas production structures. In order to study the mechanical behavior of the structural members in blast and fire, an experimental investigation has been carried out for a steel tubular T-joint without a fire-proof coating. The specimen was impacted first and then heated up under constant loading. It aims to investigate the failure mode, the critical temperature, and the temperature distribution of the T-joint at elevated temperatures; and furthermore to probe the influence of the impact load on the mechanical behavior of the joint by comparing with the results in a former test without any impact load. The experimental results show that the failure mode of the specimen was caused by the local buckling of the chord wall, which is the same as what are usually observed at ambient temperature. However the critical temperature of the impacted specimen is 690 °C, which is higher than the one without impact loading. The test results are then used to validate the numerical analysis in the future work.