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采用ER-309焊丝焊接了TCS345,T4003,Nirosta 4003,JFE410RW四种铁素体不锈钢,用金相方法分析了四种母材、接头的显微组织,通过电化学极化曲线测量,对母材和焊接接头的耐腐蚀性能进行了评价.结果表明,TCS345和T4003铁素体不锈钢与Nirosta 4003和JFE410RW铁素体不锈钢的主要区别是钛和锰含量偏低,尤其是钛含量少,导致TCS345和T4003铁素体不锈钢的晶粒长大倾向较Nirosta 4003和JFE410RW铁素体不锈钢的明显.铁素体不锈钢焊接接头存在较大的热影响区,热影响区的组织与母材晶粒相比,其晶粒明显粗大;TCS345铁素体不锈钢的晶粒长大严重,Nirosta 4003和JFE410RW铁素体不锈钢的铁素体晶粒尺寸比TCS345略小,晶粒长大不明显.在1mol/L Na2SO4溶液中,TCS345和JFE410RW不锈钢母材的腐蚀性能优于T4003和Nirosta 4003. 相似文献
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铸造奥氏体不锈钢有强磁性,因此无法满足客户要求。采用OM、SEM和XRD对铸造奥氏体不锈钢的显微组织进行观测,研究了铸造奥氏体不锈钢有强磁性的原因,并依据凝固理论和Schaeffler模型分析,提出解决措施。结果表明:铸造奥氏体不锈钢由奥氏体、网状或小块状的δ铁素体和铬的碳化物组成,铁素体含量过高导致其具有强磁性。通过调整元素含量,降低Cr、Si、Mo、Nb等铁素体形成元素,增加Ni、C、N、Mn、Cu等奥氏体形成元素,可以减少铁素体含量。通过理论计算尽可能减少Ni含量,进而控制铸造成本。 相似文献
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核电焊接用奥氏体不锈钢组织中铁素体相的作用和定量 总被引:1,自引:0,他引:1
一定比例的铁素体相存在于核电用奥氏体不锈钢组织,包括奥氏体不锈钢堆焊层、奥氏体不锈钢对接焊缝、铸造奥氏体不锈钢等.其中铁素体相的形态和含量对奥氏体不锈钢组织的性能有一定的影响,因此分析其影响机理和确定其比例限值是控制奥氏体不锈钢产品质量所必须的. 相似文献
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国内某电站在建造过程中,部分奥氏体不锈钢厚壁管在焊接后进行PT检验时发现焊缝存在大量裂纹。经分析研究,认为裂纹的产生原因与焊缝熔敷金属中δ铁素体含量偏低、P,Si含量偏高、焊接应力大等因素有关。为此对焊缝产生裂纹的原因进行了分析,为不锈钢厚壁管的焊接积累了经验。 相似文献
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M. B. Reynolds J. R. LowJr. L. O. Sullivan 《JOM Journal of the Minerals, Metals and Materials Society》1955,7(4):555-559
The effect of neutron bombardment upon the stability of type 347 austenitic stainless steel has been investigated by a magnetic technique. The relation of the ferrite content of a stainless steel to its magnetic properties is given, and an apparatus suitable for the measurement of the ferromagnetic saturation induction of small specimens is described. Results of measurements on irradiated specimens are tabulated. Exposure to a neutron flux was found to cause a slight increase in the ferrite content of type 347 stainless steel, the change increasing with increasing length of exposure and with increasing initial ferrite content. The similarity of the effect of irradiation to the effect of annealing is pointed out. Possible effect of irradiation upon density of austenitic stainless steel is discussed. 相似文献
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在冶炼含稀土Ce的2Cr13不锈钢时采用Fe-Ce中间合金代替纯Ce以获得较满意的收得率,然后对试样进行锻造及热处理,最后通过对试样进行显微组织观察及析出相的成分分析,来研究稀土Ce的残留量及对2Cr13不锈钢组织的影响。结果表明:添加Fe-Ce中间合金可以使2Cr13不锈钢中稀土的收得率达35%以上。稀土Ce的加入影响Fe-Fe3C相图中各相区的位置,在相同的淬火加热温度下出现了铁素体组织,并且含Ce量越多,得到的铁素体组织越多。Ce还可以有效减少钢中碳化物的偏聚和析出。 相似文献
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《Science & Technology of Welding & Joining》2013,18(1):57-62
AbstractThe objective of the present study was to investigate the effect of nitrogen additions to the shielding gas on the ferrite content and residual stress in austenitic stainless steels. Autogenous gas tungsten arc (GTA) welding was applied on austenitic stainless steels 304 and 310 to produce a bead on plate weld. The delta ferrite content of the weld metals was measured using a Ferritscope. The residual stress in the weldments was determined using the hole drilling strain gauge method. The present results indicated that the retained delta ferrite content in type 304 stainless steel weld metals decreased rapidly as nitrogen addition to the argon shielding gas was increased. The welding residual stress increased with increasing quantity of added nitrogen in the shielding gas. It was also found that the tensile residual stress zone in austenitic stainless steel weldments was extended as the quantity of added nitrogen gas in the argon shielding gas was increased. 相似文献
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《Science & Technology of Welding & Joining》2013,18(4):315-320
AbstractThe aim of this research is to study the effect of an activating flux, two shielding gases (100%Ar and 50%Ar z 50%He) and a range of weld currents on the microstructure of autogeneous A-TIG welds on an austenitic stainless steel. Metallographic, Mössbauer, X-ray diffraction and magnetic permeability methods were used in the study to evaluate ferrite content in the welds. The increase in welding current coarsened the microstructure and increased the retained ferrite content in welds made with and without flux. The activating flux increases the ferrite content and changes the distribution of ferrite in the welds. The influence of flux on ferrite content is less significant in Ar/He than in Ar shield welds. The process of filling steel samples, currently used in the Mössbauer method, drastically changes the microstructure of the parent and melted austenitic stainless steels. 相似文献
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介绍了347H不锈钢焊后热处理分类,分析了奥氏体不锈钢焊后热处理国内外标准现状。目前国内外标准对347H不锈钢管道焊后热处理的规定不一致,NB/T 10068—2018提出以操作温度和厚度范围作为347H不锈钢焊后热处理实施条件,为制氢装置用347H承压管道是否进行焊后热处理提供了指引,具有一定的参考意义。但该标准部分条款尚不完善,在铁素体测量顺序、铁素体含量合格值和铁素体测量方法方面还存在一定的问题,建议应将焊缝铁素体含量测量调整至焊后热处理前,取消固溶+稳定化热处理后的铁素体数为3 FN的下限值,增加E(R)16.8.2型熔覆金属铁素体含量合格值要求,同时明确铁素体含量检测方法。该标准关于焊后稳定化热处理实施条件的规定尚不完善,建议应结合工程实践经验和国外先进标准,设置焊后热处理豁免条件,对于操作温度≥500℃的薄壁和焊接接头拘束度较小工件,豁免其焊后热处理,以维持标准的科学性和先进性。NB/T 10068—2018未充分做好专利信息披露工作,后续应做好专利信息披露,防止出现知识产权劫持标准的状况。 相似文献
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为了探讨氮含量及固溶温度对21-6-9不锈钢组织和硬度的影响,分别在950、1000、1050和1100 ℃对3种不同氮含量的热轧态21-6-9不锈钢进行1 h固溶处理,通过光学显微镜观察其组织结构,结合Thermo-Calc热力学计算对试验钢的微观组织进行分析,并对其进行硬度测试。结果表明,0.20%~0.28%N的21-6-9不锈钢热轧后沿轧制方向析出铁素体,且钢中铁素体经950~1100 ℃固溶处理可消除,当N含量达到0.34%时,试验钢中不再出现铁素体。随着固溶处理温度的升高,21-6-9不锈钢的晶粒组织长大,硬度降低。N含量的增加可显著提高固溶态21-6-9不锈钢的硬度,其增加程度随固溶处理温度的升高而减弱。 相似文献