表面机械研磨处理对316L不锈钢组织和性能的影响

对2.8mm厚的316L不锈钢板的上下表层进行机械研磨处理(SMAT),对经过不同时间的SMAT后的样品的表层组织进行金相观察,并测量SMAT不同时间的样品的硬度、抗拉强度.结果表明,经过表面机械研磨处理不同时间后,在316L不锈钢板表层获得了不同厚度的表面强化层,强化层组织为沿厚度方向由纳米晶层向微米晶层过渡的梯度组织;随着SMAT时间的增加,总的强化层厚度增加;表面组织的变化导致了表面硬度明显增加,整体材料的屈服强度增加;表面机械研磨处理时间对性能的影响并非线性增加,表面硬度和整体材料的屈服强度在处理5min时增加显著,处理时间继续增加到15、30和60min,它们的增加速度很小.拉伸断口表面形貌的扫描电镜观察表明,经过5min处理后的样品,表层的剪切唇变形区域面积增加,断口微观特征为长条状的韧窝,但是随着处理时间的增加,剪切唇区的尺寸并没有继续增加,而是开始下降,表面硬化区域的增加造成了塑性变形能力的下降.     

粉末形貌对选区激光熔化316L不锈钢力学性能的影响

以气雾化316L不锈钢粉为原料,结合等离子球化和选区激光熔化技术制备了不锈钢块体,并用XRD、SEM、激光粒度仪、振实密度仪和万能力学试验机等对等离子球化粉体和选区激光不锈钢块的组织结构和性能进行了表征.结果表明:316L不锈钢粉经等离子球化处理后,不规则扁平状颗粒数量减少,球形颗粒数量增加,振实密度与松装密度的比值(...     

316L不锈钢扩散焊接头的微观结构和力学性能

针对不同焊接参数的含镍中间层316L不锈钢扩散焊接头,进行室温和550℃高温拉伸实验,采用SEM、XRD和金相显微镜分析接头区域的微观结构和相分布。结果表明:接头的室温力学性能随焊接温度的提高而降低,而高温力学性能随温度的提高而提高。XRD分析表明,焊接过程中产生的Fe0.64Ni0.36导致接头区域的相组成不均一;在高温拉伸实验时,DB2和DB3接头中的Fe0.64Ni0.36发生相变,强度和塑性更好的FeNi3是接头高温强度提高的原因。     

电弧喷涂316L不锈钢涂层的结构与性能

采用电弧喷涂优化工艺制备316L不锈钢涂层,利用扫描电镜、能谱仪和X射线衍射仪等对涂层的组织及物相进行分析,同时对涂层的硬度、结合强度进行了测定。结果表明：涂层具有典型的层状形貌,涂层截面较为致密,局部区域出现粗大孔洞;涂层与基体之间主要为机械结合,结合强度较高;涂层硬度的最大值出现在涂层中部,靠近界面的基体组织发生加工硬化。     

Corrosion behaviour of 316L stainless steel manufactured by selective laser melting

This work investigates the electrochemical behaviour of an AISI 316L stainless steel produced by selective laser melting (SLM) and compares its behaviour with that of wrought stainless steel with similar chemical composition. The SLM stainless steel specimens are tested in the as‐produced condition without stress relief or recrystallization heat treatments. The electrochemical tests are carried out in two electrolytes: 3.5 wt% NaCl solution with neutral pH and with pH of 1.8. At the macroscale, the microstructure of the SLM specimens is determined by the laser scanning pattern and displays an overlapping network of melt pools. At the microscale, the SLM specimens exhibit a cellular/columnar dendritic structure with submicrometric cell size. Electrochemical measurements highlight a more extended passive range for SLM stainless steel in both neutral and acid electrolytes indicating higher protective properties of the oxide film on SLM specimens. In contrast to the wrought material, the refined microstructure of the SLM specimens promotes a very shallow morphology of attack without deep penetration in the bulk.     

Electropolishing of 316L stainless steel for anticorrosion passivation

316L stainless steel is deemed an indispensable material in the semiconductor industry. In many instances, the surface of the production equipment needs to be treated for low-corrosion passivation, good finish, weldability, and cleanliness. The process characteristics of electropolishing meet these requirements well. The current study investigates the effects of the major processing parameters on the anticorrosion performance and the surface roughness. The electrolyte with 10% water content and a ratio between H₂SO₄ and H₃PO₄ of 4 and 6 has been proven to be successful, showing no corrosion pitting points on the specimen surface. The electrolyte temperature of 85±10 °C and the electrical current density of 0.5 to 1.0 A/cm² are found to be optimal. The processing time beyond 3 to 5 min produces no further improvement. The addition of 10% glycerin provides a very fine surface (maximum roughness of 0.05 μm), while the anticorrosion performance is deteriorated. The results obtained are useful for the manufacture of the semiconductor equipment.     

Sintering response of austenitic (316L) and ferritic (434L) stainless steel consolidated in conventional and microwave furnaces

This study compares the effect of heating mode on the densification, microstructure, strength and hardness of austenitic and ferritic stainless steel. The compacts were sintered in a radiatively heated (conventional) and a 2.45 GHz microwave furnace. Both 316L and 434L compacts couple with microwaves and heat up to the sintering temperature rapidly (45 °C/min). The overall processing time was reduced by about 90% through microwave sintering. While the microwave sintered compacts exhibit a finer microstructure, there is no corresponding improvement in densification and mechanical properties. This has been correlated with elongated and irregular pore structure.     

奥氏体不锈钢316L在ECAP过程中的组织演化及力学性能

对奥氏体不锈钢316L进行等效应变为1.02的6道次室温等通道挤压(ECAP)试验。结果表明,在ECAP挤压过程中316L发生了剪切滑移变形和孪生变形及晶粒碎化,经过4和6道次挤压后分别得到平均晶粒尺寸约80 nm和约61 nm的均匀分布的等轴晶粒。在1道次ECAP挤压后316L的抗拉强度由674 MPa增加到984 MPa, 规定塑性延伸强度则由594 MPa增加到922 MPa,维氏显微硬度由116.33 HV增加到328.31 HV,但是塑性下降严重,可以通过600 ℃后续退火处理进行改善。     

316L不锈钢表面激光熔覆Stellite-F合金层的电化学腐蚀行为

采用CO₂激光器在316L不锈钢表面熔覆Stellite-F合金,通过电化学方法研究了Stellite-F熔覆合金层在5wt%NaCl溶液中的腐蚀行为。结果表明:与316L不锈钢相比,与基材呈冶金结合的Stellite-F合金层自腐蚀电位较正、自腐蚀电流密度较小,无点腐蚀现象出现,耐海水腐蚀性能较好;研究发现,熔覆合金层物相主要由γ-Co固溶体与Ni₃C、Cr₂₃C₆碳化物构成,在盐溶液中其腐蚀失效机制为选择性腐蚀,即固溶体合金相作为阳极被腐蚀浸出,碳化物相得到阴极保护暴露析出,同时固溶体相中的Co、Ni组分优先被腐蚀浸出,其余组分形成海绵状结构。     

生物医用材料316L不锈钢的磨损腐蚀特性研究

对人工关节常用的生物医用材料316L不锈钢在蒸馏水和Hank’s模拟体液条件下的腐蚀磨损行为进行了研究,通过改变载荷和磨损时间考察了不同因素对其腐蚀磨损的影响规律。在Hank’s模拟体液条件下,316L不锈钢在10kg载荷下的磨损比在其他载荷条件下都要小。同载荷条件下,该钢在Hank’s中的磨损量大于蒸馏水中的,并有晶间腐蚀倾向。     

Effects of cooling rate on mechanical properties and corrosion resistance of vacuum sintered powder injection molded 316L stainless steel

This study presents the results of corrosion behavior of powder injection molded 316L stainless steel parts sintered in vacuum. The feedstocks of metal powder and plastic binder were prepared and their viscosity was measured. Green samples were injection molded and binder was removed from the green parts. Brown test parts were sintered at 1325 °C with heating rate of 5 °C/min and 10 °C/min for 2 h followed by the same cooling rate. Corrosion response of the sintered test samples was measured by weight loss method in Ringer's Solution of pH 7.4 for 15 days. The test samples using cooling rate 10 °C/min showed higher mechanical properties and improved corrosion resistance compared to those sintered at low heating and cooling rate. High cooling rate reduced the evaporation of Cr and developed passive chromium oxide layer on the test samples resulting improved corrosion resistance.     

不同热塑性蜡基粘接剂对316L注射成型件性能的影响

用金属注射成型方法研究三种热塑性蜡基粘接剂(高密度聚乙烯、高密度聚乙烯/聚丙烯、聚丙烯)对316L不锈钢尺寸稳定性及其机械性能的影响,对三种热塑性蜡基粘接剂溶剂脱脂过程进行了分析。实验结果表明用高密度聚乙烯/聚丙烯热塑性蜡基粘接剂得到的316L不锈钢注射成型件尺寸稳定性及机械性能较好,溶剂脱脂时间较短、效果较好,其长、宽、高三维尺寸稳定性比聚丙烯热塑性蜡基粘接剂得到的注射成型件分别高46 %,40 %,20 %,密度、硬度和拉伸强度分别为7.28 g/cm₃、72.3 HRB和579MPa。     

基于非晶态中间层合金的316L不锈钢TLP焊接

研究了瞬时液相扩散焊316L不锈钢用中间层合金的成分和相结构,分析了中间层合金成分及焊接工艺参数对接头组织和性能的影响.结果表明,Ni-Si-B中间层合金具有非晶态结构,在TLP焊接316L不锈钢过程中展现出良好的润湿性和填缝性,接头组织连续性好,基本上无焊接缺陷.焊缝组织为Ni（Fe）固溶体和少量Cr3C2化合物,母...     

Surface modification of 316L stainless steel with high-intensity pulsed ion beams

The surface of 316L stainless steel was irradiated by high-intensity pulsed ion beams (HIPIB) at ion current density of 100, 200 and 300 A/cm² with 10 shots. The surface morphology and the phase structure in the near surface region of original and treated samples were analyzed with scanning electron microscope (SEM) and X-ray diffraction (XRD). Electron probe microanalysis (EPMA) was used to study the distribution of elements on the irradiated surfaces. It is found that the HIPIB irradiation can smooth the surface of the targets, and a preferred orientation presents in the surface layer of the treated samples. Otherwise, selective ablation of impurities occurs during the interaction between HIPIB and the targets. Due to the compress stress wave induced by the bombardment, the microhardness is increased significantly in a depth range of up to 200 μm, which reduces the friction coefficient of the treated surfaces and improves the wear resistance of them. Because the grain size reduces and the impurities content decreases in the irradiated surface layer, the electrochemical corrosion resistance is enhanced. In addition, HIPIB irradiation prolongates the fatigue life of 316L at room temperature due to a combination of the smooth surface and the high dislocation density in the surface layer of the treated samples.     

Effect of DC plasma nitriding temperature on microstructure and dry-sliding wear properties of 316L stainless steel

A wear resistant nitrided layer was formed on 316L austenitic stainless steel substrate by DC plasma nitriding (DCPN). The structural phases, micro-hardness and dry-sliding wear behavior of the nitrided layer were investigated by optical microscopy (OM), X-ray diffraction (XRD), scanning electron microscopy (SEM), energy dispersive X-ray analysis (EDS), micro-hardness tester and ring-on-block wear tester. The results show that a single expanded austenite layer (S-phase) and a single CrN nitride layer were formed at 400 °C and 480 °C, respectively. In addition, the S-phase layers formed on the samples exhibited the best dry-sliding wear resistance under ring-on-block contact configuration test. Wear of the untreated 316L was sever and characterized by strong adhesion, abrasion and oxidation mechanism, whilst wear of the DCPN-treated 316L was mild and dominated by plastic deformation, slight abrasion and frictional polishing.     

高温酸性溶液中316L不锈钢/Ni-Cu-P镀层的耐蚀性能

为了改善316L 不锈钢在高温酸性溶液中的耐蚀性,采用化学镀技术在316L 不锈钢表面沉积高铜高磷Ni?Cu?P 镀层。采用扫描电镜(SEM)、能谱仪(EDS)和 X 射线衍射仪(XRD)对其结构进行分析,利用极化曲线、阻抗谱(EIS)及浸泡腐蚀试验对其在高温酸性溶液中的耐蚀性进行研究。结果表明,Ni?Cu?P 镀层由铜含量分别为19.98%和39.17%(质量分数)两种类型的胞状组织组成;在高温酸性溶液中,这种新型Ni?Cu?P镀层可显著改善316L不锈钢的耐蚀性;镀态镀层的耐蚀性优于热处理态的;镀态镀层和经673 K热处理镀层的腐蚀机制是选择性腐蚀,而经773和873 K热处理镀层的腐蚀机制为点腐蚀。     

离子硬化工艺在316L不锈钢阀内件中的应用

对316L奥氏体不锈钢进行离子渗氮(PN)和离子碳氮共渗(PNC)处理,利用光学显微镜、显微硬度计、电化学工作站、粗糙度检测仪和三坐标测量仪对试样渗层厚度、显微硬度、耐腐蚀性、表面粗糙度和变形量进行讨论分析。结果表明:316L钢经离子碳氮共渗处理后的渗层硬度分布较好,可提高耐腐蚀性能。离子碳氮共渗技术可应用于阀内件(包括球芯和阀座)的表面硬化处理,在保证零件尺寸配合公差的条件下,大幅提高阀内件的表面硬度。     

Electrochemical and XPS studies of AISI 316L stainless steel after electropolishing in a magnetic field

The thermodynamic stability and corrosion resistance of surface oxide layer are the most important features of stainless steels. Electrochemical polishing (EP) is the most extensively used surface technology for austenitic stainless steels. We have modified this surface technology by introducing a magnetic field to the system. With this new process called the magnetoelectropolishing (MEP) we can improve metal surface properties by making the stainless steel more resistant to halides encountered in a variety of environments.In this paper, the corrosion research results are presented on the behaviour of the most commonly used material - medical grade AISI 316L stainless steel. The corrosion investigations have been concerned on the open circuit potential (OCP), electrochemical impedance spectroscopy (EIS), and polarisation curves studies in the Ringer’s body fluid under room temperature (25 °C). The X-ray photoelectron spectroscopy (XPS) was performed on 316L samples after three treatments: MP - abrasive polishing (800 grit size), EP - conventional electrolytic polishing, and MEP - magnetoelectropolishing. The comparison of the corrosion behaviour of the stainless steel’s surface after these processes was also carried out. The purpose of XPS studies was to reveal the surface film composition and the reason of this modified corrosion behaviour. It has been found that the proposed MEP process modifies considerably the composition of the surface film and improves the corrosion resistance of the same 316L SS studied.     

固溶温度对316LN不锈钢组织及力学性能的影响

用金相显微镜、SEM、拉伸、冲击试验机等研究了固溶温度对316LN不锈钢组织及力学性能的影响.结果表明,固溶温度对316LN不锈钢影响显著,随固溶温度升高晶粒尺寸增大,强度降低,塑性保持相对稳定,抗冲击性能提高,且冲击断口均显示为颜色灰暗的塑性韧窝形貌,经1050℃固溶处理后的强塑性匹配较好,抗冲击性能优良,晶粒度达到7级以上.     

阀门球芯316L不锈钢小空间TIG焊接工艺

采用填丝的TIG焊接方法对不锈钢球芯流道口进行小空间全位置自动焊接。通过设计可进行小空间作业的TIG焊枪,配合送丝机气保托罩紫铜散热夹与小车行走装置,搭建自动化焊接平台。在阀门球芯的小空间内多重氩气保护下,开展不锈钢球芯流道口V形焊缝的焊接。焊前清理焊缝及周围区域的杂质油污,焊接时使用高纯氩进行严格的惰性气氛保护,获得各项性能均符合技术要求的焊缝。焊后对焊缝区域进行微观组织和力学性能的测试评定,分析缺陷的产生及原因,并改善焊接工艺参数。测试焊缝、热影响区附近及母材位置的硬度,绘制相应的工艺曲线,获得最佳的工艺参数组合。