12%Cr铁素体不锈钢焊接接头组织及韧性研究

对四种不同成分的12%Cr铁素体不锈钢做了焊接性试验。分析焊接接头的组织,测量了焊接接头的低温冲击功。试验结果表明,随着碳含量的增加,焊接粗晶区组织由单相铁素体逐渐转变成以马氏体为主,粗晶区宽度变窄,晶粒尺寸变小。细晶区组织以马氏体为主,组织细小均匀。熔合线处和热影响区的低温冲击功相比母材均显著降低。断裂路径分析结果表明,窄的粗晶区宽度和小的晶粒尺寸使断裂路径经过更多的奥氏体焊缝区,提高了整体的冲击韧性。     

热输入对铁素体不锈钢焊接HAZ组织的影响研究

通过调整焊接速度来研究热输入对00Cr12铁索体不锈钢的MAG焊接接头HAZ组织的影响，总结了热输入对HAZ组织的影响规律，并提出了焊接该种不锈钢的优化工艺措施。     

铌、钛对445M铁素体不锈钢韧性的影响

 通过真空冶炼、锻造、热轧和不同固溶处理温度试验制备出含有不同微合金元素含量的445M铁素体不锈钢，结合其冲击试验，运用金相显微镜、扫描电子显微镜及能谱仪等分析方法，探讨了微合金化对其韧性的影响。结果表明：化学元素铌和钛的加入，在晶粒内部和晶界上形成了TiN、NbC和(Nb，Ti)(C，N)析出相，稳定了钢中的碳、氮元素，防止由铬的碳氮化物析出而引起的晶间腐蚀，但对钢的冲击韧性有一定影响。采用单铌作为稳定化元素钢的冲击韧性优于单钛稳定钢；添加少量的钛，采用Nb+Ti双稳定钢，也可获得优异的冲击韧性，并且能够降低生产成本。     

退火对超纯铁素体不锈钢焊接热影响区组织、性能的影响

利用热模拟试验机研究了退火对一种超纯铁素体不锈钢(板厚12 mm)焊接热影响区微观组织以及室温冲击韧性的影响。结果发现,热轧退火后的铁素体形貌由长条状转变为等轴状;与热轧态相比,在相同焊接热模拟条件下,退火态试样晶粒尺寸较大,但室温冲击功得到明显改善。     

热处理工艺对12%Cr铁素体不锈钢组织性能的影响

以12%Cr铁素体不锈钢为研究对象,研究了不同退火方式、退火工艺对12%Cr铁素体不锈钢热轧板和冷轧板组织、力学性能、耐腐蚀性能、成形性能的影响。结果显示,12%Cr铁素体不锈钢高温下存在铁素体—奥氏体相变过程,在双相区退火快冷后有马氏体组织生成。通过在热退过程中引入奥氏体相变和马氏体相变,可以显著细化最终产品晶粒,提高最终冷轧产品的强度、硬度,同时保持材料耐腐蚀性能不变。该工艺生产的产品可以适用于高强度的应用场合,打破了传统12%Cr铁素体不锈钢热轧后只能采用罩式炉退火的束缚,针对产品的最终用途可以采用不同的退火方式和退火工艺进行生产。     

12%Cr铁素体不锈钢的焊接热影响区组织特征

针对12%Cr铁素体不锈钢,利用光学显微镜、扫描电镜,对在不同焊接热输入条件下的显微组织种类进行观察,得出热影响粗晶区的组织变化规律;应用Thermal-cal软件,确定了12%Cr铁素体不锈钢在焊接热循环条件下发生相变的温度区间,以及微合金元素Ti和Nb的析出相图.给出在焊接热循环作用下,改善铁素体不锈钢焊接接头热影响区韧性的建议,即焊接热影响粗晶区存在适量的马氏体;钢中添加微量元素Ti可抑制粗晶区晶粒长大,其作用优于Nb.     

化学成分对430铁素体不锈钢凝固结构的影响

在430铁素体不锈钢成分体系基础上,研究了成分的变化对430铁素体不锈钢凝固结构的影响。经试验发现,含碳量的变化显著影响430铁素体不锈钢的凝固组织,含碳量越高,铸锭中的等轴晶比率越大;而Ti元素的加入,虽然有利于430铁素体不锈钢铸锭中等轴晶的形成,但需要保证TiN在钢的液相线附近析出,促进钢的异质形核,从而优化钢的凝固结构。     

稀土改善430铁素体不锈钢冲击韧性的作用机理

 采用金相、扫描电镜和能谱等分析手段,研究了微量稀土对430铁素体不锈钢在室温和低温下的横向冲击性能的影响。研究结果表明,稀土夹杂物减缓了裂纹的扩展。加稀土的试样断口为韧性撕裂,不加稀土的试样断口为解理断裂。加微量稀土的试样横向冲击性能比不加稀土的试样大幅度提高,最高提高了5倍。     

非调质厚板材焊接热影响区晶内铁素体相变研究

研究了添加微量元素（Ti、V、Zr、Nb）低合金高强度钢焊接热影响区（HAZ）晶内针状铁素体（IGF）的形成机理，并采用TEM和EDS观察和分析HAZ中晶内针状铁素体形成核心的化学成分和结构及核心周边锰含量变化。结果表明：添加微量元素可有效阻止HAZ晶粒粗大化，抑制离异珠光体出现；HAZ中以ZrO2氧化物为核心形成的复合化合物ZrO2＋（Zr，Ti）2O5＋MnS＋V（C、N）＋NbN能有效促进IGF形成；复合化合物周围的MnS造成复合化合物周围约40nm的Mn贫化区，Mn贫化区锰含量大小与生成IGF量有良好对应关系。     

钒对18Cr-2Mo铁素体不锈钢性能的影响

 利用Thermo-Calc热力学软件、扫描电子显微镜、X射线衍射仪及透射电镜等分析方法,研究了不同钒含量对单铌稳定18Cr-2Mo铁素体不锈钢微观组织、力学性能和点腐蚀性能的影响规律。结果表明：添加钒后的析出相主要是NbC和VN,弥散分布于晶内和晶界,其中NbC的尺寸为100~250nm;随着钒含量的增加,试验钢的晶粒尺寸及屈服强度变化不明显,而冲击韧性及点腐蚀性能逐步得到改善和提高,当wV=0.36%时,钢的韧脆?湮露扔稍嫉?10℃下降至-30℃,点腐蚀电位由0.38V提高至0.42V。     

Effect of Autogenous Arc Welding Processes on Tensile and Impact Properties of Ferritic Stainless Steel Joints

 The effect of autogeneous arc welding processes on tensile and impact properties of ferritic stainless steel conformed to AISI 409M grade is studied. Rolled plates of 4 mm thickness have been used as the base material for preparing single pass butt welded joints. Tensile and impact properties, microhardness, microstructure, and fracture surface morphology of continuous current gas tungsten arc welding (CCGTAW), pulsed current gas tungsten arc welding (PCGTAW), and plasma arc welding (PAW) joints are evaluated and the results are compared. It is found that the PAW joints of ferritic stainless steel show superior tensile and impact properties when compared with CCGTAW and PCGTAW joints, and this is mainly due to lower heat input, finer fusion zone grain diameter, and higher fusion zone hardness.     

439铁素体不锈钢的研制

439是在430不锈钢基础上降低C＋N含量，添加Nb、Ti等稳定化元素发展起来的新型不锈钢材料，已逐步代替304不锈钢应用于电梯面板等行业。为开发满足用户使用要求的439不锈钢，试验室研究了成分、热处理制度对439不锈钢性能的影响，结果表明：Ti、Nb稳定化元素的添加对改善439不锈钢综合性能比较有利、热轧439退火再冷轧可明显改进深冲性能。生产试制结果表明，宝钢生产的439冷轧产品完全能满足用户对材料的性能要求。     

Effect of Welding Processes on Tensile and Impact Properties, Hardness and Microstructure of AISI 409M Ferritic Stainless Joints Fabricated by Duplex Stainless Steel Filler Metal

The effect of welding processes such as shielded metal arc welding, gas metal arc welding and gas tungsten arc welding on tensile and impact properties of the ferritic stainless steel conforming to AISI 409M grade is studied. Rolled plates of 4 mm thickness were used as the base material for preparing single pass butt welded joints. Tensile and impact properties, microhardness, microstructure and fracture surface morphology of the welded joints have been evaluated and the results are compared. From this investigatio.n, it is found that gas tungsten arc welded joints of ferritic stainless steel have superior tensile and impact properties compared with shielded metal are and gas metal arc welded joints and this is mainly due to the presence of finer grains in fusion zone and heat affected zone.     

Comparison of Friction Stir and Gas Tungsten Arc Weldments of Modified 12 wt.% Cr Ferritic Stainless Steel

This paper presents the comparative evaluation of microstructural features and mechanical properties of a friction stir welded (solid‐state) and gas tungsten arc welded (fusion weld) 409 M grade ferritic stainless steel joints. Optical microscopy, microhardness, transverse tensile and impact tests were performed. The coarser ferrite grains in the base material are changed to very fine grains consisting of a duplex structure of ferrite and martensite due to the rapid cooling rate and high strain induced by severe plastic deformation caused by frictional stirring. On the other hand, grain growth was observed in the fusion zone as well as heat affected zone of the gas tungsten arc welded joint resulting in deterioration of mechanical properties.