不锈钢和碳钢在含酚酸性废水中耐蚀性

用恒电位极化曲线法和旋转挂片失重法研究了３１６Ｌ、３０４不锈钢和２０号碳钢在３０℃，ｐＨ＝２．１０的含酚酸性废水中的耐蚀性。结果表明３１６Ｌ和３０４不锈钢具有优良的耐蚀性，而２０号碳钢不耐蚀。含酚酸性废水中所含甲醛对３１６Ｌ和３０４不锈钢有缓蚀作用，与相同ｐＨ的盐酸溶液中腐蚀速度相比，其缓蚀率为７０％。     

焊接接头断裂韧度JIC统计分布函数的蒙特卡罗模拟

建立了用于确定焊接接头断裂韧度ＪＩＣ统计分析函数的蒙特卡罗模拟方法，对３１６Ｌ奥氏体不锈钢焊接接头ＪＩＣ的统计分布函数进行了统计模拟，结果表明ＪＩＣ最佳拟合分布为威布尔分布。分析了样本数量对蒙特卡罗模拟结果的影响。     

焊接接头断裂韧度J_(ⅠC)统计分布函数的蒙特卡罗模拟

建立了用于确定焊接接头断裂韧度ＪⅠＣ统计分析函数的蒙特卡罗模拟方法。对３１６Ｌ奥氏体不锈钢焊接接头ＪⅠＣ的统计分布函数进行了统计模拟，结果表明，ＪⅠＣ的最佳拟合分布为威布尔分布。分析了样本数量对蒙特卡罗模拟结果的影响。     

超低碳奥氏体不锈钢在低周疲劳中的组织结构研究

研究了超低碳３１６Ｌ、３１６ＬＮ奥氏体不锈钢在常温下的低周疲劳行为及组织结构变化规律。结果表明，材料在循环变形过程中呈现不同程度的硬化、软化，应变幅的增加促进硬化，缩短低周疲劳寿命。透射电镜分析表明，奥氏体内的组织结构的演变过程与循环应力特性曲线的变化规律相呼应。     

电厂凝汽器不锈钢管的耐蚀性及选材试验

用电化学方法对电厂凝汽器工况条件下３０４、３１６Ｌ、３１７Ｌ不锈钢管的耐蚀性能作了对比研究，针对电厂用冷却水质进行了初步选材试验，并与ＨＳｎ７０－１Ａ黄铜管、ＢＦ３３０－１－１白铜管作了比较。结果表明：不锈钢管垢耐蚀性能比铜管好得多；不同品牌不锈钢的耐蚀性差异较大，应用时应根据水质工况合理选材，确定合适的不锈钢管材。     

NaSCN溶液中耐腐蚀材料的选择

用失重法和电化学法研究了Ａ３钢化学镀镍层、ＡＴＳＩ３１６和ＡＩＳＩ３０４Ｌ不锈钢在ＮａＳＣＮ溶液中的腐蚀行为。结果表明，ＡＩＳ３１６不锈钢在ＮａＳＣＮＢ溶液中具有优良的耐蚀性。其成分中Ｍｏ能抑制点蚀。Ａ３钢Ｎｉ－Ｐ镀层在ＮａＳＣＮ溶液中可能取代不锈钢，但镀层针孔及缺陷问题有待解决。     

耐碱泵用新型KM－1双相铸造不锈钢的研究

在本项研究工作中，设计了用于具有固相颗粒的高温碱条件下的双相铸造不锈钢的组织及其化学成分。采用金相显微镜和Ｘ射线衍射的方法分析研究了试验钢的组织，通过均匀腐蚀、电化学腐蚀、晶间腐蚀等腐蚀试验方法研究了钢的耐蚀性能。试验及现场试运转结果表明，具有双相组织的ＫＭ－１铸造不锈钢在具有固相颗粒高温碱介质条件下具有较好的耐蚀性能，由ＫＭ－１制做的泵件寿命比常用的３１６提高了约一倍。此外，ＫＭ－１钢还具有良好的铸造性能。     

耐碱泵用新型KM—1双相铸造不锈钢的研究

在本项研究工作中，设计了用于具有固相颗粒的高温碱条件下的双相铸造不锈钢的组织及其化学成分。采用金相显微镜和Ｘ射线衍射的方法分析研究了试验钢的组织，通过均匀腐蚀，电化学腐蚀，晶间腐蚀等腐蚀试验方法研究了钢的耐蚀性能。试验及现场试运转结果表明，具有双相组织的ＫＭ－１铸造不锈钢在具有固相颗粒高温碱介质条件下具有较好的耐蚀性能，由ＫＭ－１制做的泵件寿命比常用的３１６提高了约一倍。此外，ＫＭ－１钢还具有良好     

可抑制不锈钢酸洗应力腐蚀的缓蚀剂

采用慢应变法对试样进行拉伸，并结合扫描电镜观察断口形貌，结果表明苯并咪唑类化合物（ＢＭＡＴ）对３１６Ｌ，２Ｃｒ１３等不锈钢在５％ＨＣｌ中的应力腐蚀有着良好的抑制作用。     

316不锈钢应力腐蚀断裂扫描电镜研究

应用扫描电镜和Ｘ射线能量色散谱仪对３１６不锈钢应力腐蚀断口形貌、腐蚀产物及裂纹扩展的晶体学特征进行研究。结果表明,断裂为穿晶断裂,断口形貌为台阶条纹和河流花样,并有腐蚀产物和腐蚀坑等。通过对腐蚀坑形貌的研究,提出了腐蚀坑形态与晶面之间的关系,证明了３１６不锈钢在氯离子环境下的应力腐蚀开裂主要沿｛１００｝、｛１１１｝、｛１１０｝晶面扩展的机制。     

Effect of Copper and Bronze Addition on Corrosion Resistance of Alloyed 316L Stainless Steel Cladded on Plain Carbon Steel by Powder Metallurgy

A sandwich structure with cladding alloyed 316L stainless steel on plain carbon steel was prepared by means of powder metallurgy (PM) processing. Electrolytic Cu and prealloyed bronze (95Cu wt pct, 5Sn wt pct) were added in different contents up to 15% into the surface cladded 316L layers and the effect of alloying concentrations on the corrosion resistance of the 316L cladding layers was studied. The corrosion performances of the cladding samples were studied by immersion tests and potentio-dynamic anodic polarization tests in H_2S0_4 and FeCl_3 solutions. Both 316L and alloyed 316L surface layers with 1.0 mm depth produced by PM cladding had an effect to improve corrosion resistance in H2SO4 and FeCI3 solutions. Small Cu and bronze addition (4%) had a positive effect in H_2SO_4 and FeCl3 solutions. 4% Cu alloyed 316L surface layer produced by PM cladding showed similar anodic polarization behaviour to the 316L cladding layer in H_2SO_4 and FeCl_3 solutions.     

SOME CREEP/FATIGUE PROPERTIES OF TYPE 316 STEEL AT 625°C

Abstract— Strain controlled continuous cycling fatigue tests are reported on three casts of Type 316 steel; the results obtained are shown to be consistent with published data. Strain controlled creep/fatigue tests are reported involving a hold period per cycle of between 0·2 and 168 h on one batch of Type 316 steel. An empirical extrapolation of the data and one involving a linear damage summation suggest that the existing Code Case N47 creep/fatigue design curve and rules are over-conservative. A stress relaxation/fatigue endurance correlation shows some promise for predictive purposes. Although many of the mechanical test and metallurgical features observed are consistent with a fundamental crack growth extrapolation approach, further consideration of detailed aspects are necessary before it can be used with confidence. It is concluded that there are no entirely reliable methods of extrapolation currently available for Type 316 steel and longer term tests are therefore essential to reduce the extrapolation uncertainties.     

Friction and wear behaviors of a gradient nano-grained AISI 316L stainless steel under dry and oil-lubricated conditions

A gradient nano-grained (GNG) surface layer was fabricated on an AISI 316L stainless steel (SS) by using the surface mechanical rolling treatment (SMRT). Reciprocating dry and oil-lubricated sliding tests of the GNG 316L SS in air at room temperature were conducted in comparison with the coarse-grained (CG) counterpart. Worn surface morphologies and subsurface microstructures were investigated for both 316L SS samples. 316L SS with a GNG surface layer shows a significantly improved wear resistance, especially under oil-lubricated condition. The notably wear resistance enhancement of the GNG 316L SS is attributed to the GNG surface layer with high strain accommodation ability and high hardness, which can reduce the wear volume in the running-in stage effectively.     

大口径316L不锈钢管数控弯曲回弹规律研究

针对Φ123 mm×3.97 mm×350 mm规格的大口径316L厚壁不锈钢管,基于显/隐式弹塑性有限元仿真结合实验研究,对其数控弯曲卸载后的回弹现象进行了研究.采用单向拉伸试验和三维数字散斑动态应变测量方法获得了大口径316L不锈钢管大应变范围(真应变为49.02%)的力学性能参数,通过摩擦磨损实验获得管材316L不锈钢与45钢模具材料在不同压力和转速条件下的摩擦系数.基于ABAQUS平台,建立了大口径316L不锈钢管弯曲、抽芯、卸载回弹全过程数控弯曲有限元模型,并实验验证了所建模型的可靠性.研究表明,大口径316L不锈钢管回弹现象显著,在350 mm弯曲半径(相对弯曲半径D/t为2.846)条件下达到7.2°左右.芯棒伸出量e、芯球个数n和弯曲角度θ对卸载回弹有显著影响.     

Microstructure and Corrosion Resistance of Dissimilar Weld-Joints between Duplex Stainless Steel 2205 and Austenitic Stainless Steel 316L

The microstructure and corrosion resistance of dissimilar weld-joints between stainless steel SAF 2205 and stainless steel AISI 316 L were investigated. Welding was accomplished by different types of welding wires AWS ER 347, AWS ER 316 L and AWS ER 309 L. To verify soundness of welded samples, nondestructive tests were performed. Metallographic samples were prepared from cross-section areas of weldjoints to investigate microstructure of different regions of weld-joints by optical microscopy and scanning electron microscopy. Corrosion resistance of weld-joints was evaluated in NaCl solution by potentiodynamic polarization and electrochemical impedance techniques. In the weld metal AWS ER 347, the brittle sigma phase was created, resulting in the decrease of weld-joint corrosion resistance. According to the results of metallurgical investigations and corrosion tests, welding wire AWS ER 309 L was suitable for welding duplex stainless steel(SAF 2205) to austenitic stainless steel(AISI 316L) by gas tungsten arc welding(GTAW)process.     

316L不锈钢在海水中的阴极极化行为研究

为了探索316L不锈钢阴极保护有效控制电位,利用动电位极化曲线及恒电位极化法研究了316L不锈钢在天然海水和模拟闭塞液中的阴极极化行为,通过失重法研究了不同电位恒电位极化对316L不锈钢在模拟闭塞液中腐蚀控制的效果.研究表明:316L不锈钢在海水中适宜的阴极保护电位为-0.6～-0.9 V(vs.SCE),模拟闭塞液中...     

Some factors exerting an influence on the coaxing effect of austenitic stainless steels

The present paper describes some factors exerting an influence on the coaxing effect of austenitic stainless steels. Particularly, the influence of prestrain was investigated in detail. The materials used were austenitic stainless steels, type 304 and 316. Type 304N2 was also used to examine the properties of the stabilized austenitic phase in type 304. Two types of rotating bending fatigue tests, i.e. the conventional constant amplitude tests and stress‐incremental tests, were performed using the specimens subjected to the several tensile‐prestrain levels. Under the constant amplitude tests, the fatigue strengths of type 304 and 316 increased with increasing prestrain. Under the stress‐incremental tests, type 304 showed a remarkable coaxing effect, where the fatigue failure stress significantly increased regardless of the prestrain level. The coaxing effect in the unprestrained specimens was larger than those of the prestrained ones. Type 304N2 showed lower coaxing effect than type 304. In addition, the strain‐induced martensitic transformation did not occur because of the higher stability of austenitic phase in type 304N2. In type 316, the coaxing effect was dependent on the prestrain level, i.e. below 15% prestrain the coaxing effect became smaller with increasing prestrain, whereas above 25% prestrain the coaxing effect reappeared. Based on the tests results, it was considered that the coaxing effect in austenitic stainless steel was due to the mechanisms such as work hardening, strain ageing and strain‐induced martensitic transformation. The contribution of these mechanisms to the coaxing effect was different among type 304, 304N2 and 316.     

不锈钢管道在海水中的腐蚀研究

采用失重分析和电偶腐蚀测试等方法研究了气田立管采用的316L／625复合管材料在海水中的腐蚀情况，结果表明，复合管316L不锈钢和625合金在10℃海水中浸泡3个月后，平均腐蚀速率均低于0．01mm／a，而焊接接头处的腐蚀速率较大，为0．015mm／a，电偶腐蚀对316L不锈钢的影响不大，电偶腐蚀系数不超过130％。     

316L不锈钢表面纳米化后腐蚀性能研究

对表面纳米化和未经表面纳米化处理的316L不锈钢的样品分别进行点蚀实验和应力腐蚀对比实验,在3.5%(质量分数)NaCl水溶液中分别测出它们的极化曲线.结果表明,316L不锈钢表面纳米化后抗点蚀性能下降,抗应力腐蚀性能提高.对应力腐蚀断口的SEM 分析发现,316L不锈钢应力腐蚀断口有明显分区现象,断裂形式为韧性断裂,开裂通道既有穿晶型也有沿晶型.     

Predicting creep crack initiation in austenitic and ferritic steels using the creep toughness parameter and time-dependent failure assessment diagram

Methods for evaluating the creep toughness parameter,   K ^mat _c   , are reviewed and   K ^mat _c   data are determined for a ferritic P22 steel from creep crack growth tests on compact tension, C(T), specimens of homogenous parent material (PM) and heterogeneous specimen weldments at 565 °C and compared to similar tests on austenitic type 316H stainless steel at 550 °C. Appropriate relations describing the time dependency of   K ^mat _c   are determined accounting for data scatter. Considerable differences are observed in the form of the   K ^mat _c   data and the time-dependent failure assessment diagrams (TDFADs) for both the 316H and P22 steel. The TDFAD for P22 shows a strong time dependency, but is insensitive to time for 316H. Creep crack initiation (CCI) time predictions are obtained using the TDFAD approach and compared to experimental results from C(T) specimens and feature components. The TDFAD based on parent material properties can be used to obtain conservative predictions of CCI on weldments. Conservative predictions are almost always obtained when lower bound   K ^mat _c   values are employed. Long-term test are generally more relevant to industrial component lifetimes. The different trends between long- and short-term CCI time and growth data indicate that additional long-term test are required to further validate the procedure to predict the lifetimes of high temperature components.