Cu含量对耐海水腐蚀不锈钢组织与性能的影响

借助XRD、SEM等研究了0％～0．8％的Cu对20Cr-18Ni-6Mo-0．2Mn-0．8V-0．1Si耐海水腐蚀不锈试验钢力学性能的影响。结果表明：当Cu为0．3％时,抗拉强度（σb）为642Mpa;度（HRB）为93．28,延伸率（δ）为27．1％,其综合力学性能最优。     

新型耐海水腐蚀不锈钢的研究

介绍了一种耐海水腐蚀不锈钢,通过对试验钢进行化学成分设计和熔炼,对其在热处理工艺、室内点蚀浸泡、力学性能、金相组织等方面做了测试,并与316L不锈钢进行比较,指出了该钢的特点,结果表明该试验钢具有良好性能。     

耐海水和氯离子介质腐蚀的高性能不锈钢C15

扼要地介绍了Ｃ１５不锈钢的化学成分、显微组织、力学性能、耐腐蚀性能和加工性能，为选材应用提供了判据。     

双相铸造不锈钢的组织及其局部腐蚀行为

采用金相显微镜,X-射线衍射,电子探针相结合的方法,研究了不同热处理状态下的低碳高铬双相铸造不锈钢的相形态、种类、成分,量的相对变化及形成条件;研究了该钢不同热处理制度下的晶间腐蚀、点腐蚀行为,并与性能优良的K 合金进行了对比。研究结果表明,试验钢经1050℃固溶处理后,γ相数量较少且均匀分布,耐蚀性最好。     

316L不锈钢波纹管不同工艺海水腐蚀失效机理分析

316L不锈钢是一种耐蚀性和可加工性都比较好的奥氏体不锈钢,用其加工制造的波纹管,经表面处理后,可进一步提高在海水环境中使用的耐腐蚀性能,在应用过程中发现经钝化处理的波纹管在使用工况下相对较短的时间内出现穿孔,而经表面黑化处理的波纹管在同样环境下试验使用,表面锈蚀较为严重,但没有出现点蚀穿孔。本论文利用电化学极化曲线和扫描电镜观察的观察分析结果,对发现的结果进行研究。     

元素Cr、Ni对不锈钢耐蚀性能影响

奥氏体不锈钢06Crl9NilO广泛应用于高压电气行业,其耐蚀性是重要的使用性能,本文选取三类不同化学成分的不锈钢板,结合微观组织结构,通过电化学腐蚀和盐雾腐蚀系统分析,研究了三类不锈钢的耐蚀性能,结果表明,随着cr与M含量的增加,不锈钢的耐蚀性能提高,本试验为指导生产提供了技术依据。     

时效工艺对2205双相不锈钢组织与力学性能的影响

研究了时效温度和时间对2205双相不锈钢组织及力学性能的影响,并对其断口形貌进行了分析。结果表明,2205不锈钢在时效处理中析出相σ相的形核位置、形态及数量与时效温度和时间有很大关系。时效温度高时,σ相在δ/γ相界和δ相内同时形核、生长,并且易形成块状;温度低时,σ相则偏聚在δ/γ相界生核,然后向δ相内生长,σ相易形成片状组织;同时,σ相的数量也会随着时效时间的延长而增加。475℃和600℃时效后双相不锈钢的强度明显提高,韧性略有降低,微观断口以韧窝为主。750℃时效后强度有所提高,韧性明显降低,微观断口以解理平面为主。     

不锈钢微丝的制备及组织和性能研究

研究了不同直径的316L不锈钢微丝的组织和性能，并探讨了微丝制备过程中断丝的原因。结果表明，冷拉丝材退火后，随直径减小微丝的晶粒不断细化；随直径减小抗拉强度变化不大，而伸长率却逐渐下降；扫描电镜观察表明，微丝表面局部存在缺陷，而断口观察发现有非金属夹杂物存在；缺陷的存在将影响拉伸试样的伸长率，也是微丝制备过程中引起断丝的主要原因之一。     

不锈钢脚阀在酸性介质中使用寿命的研究

研究了2种阀门常用材料AISI 304和1Cr18Niu9Ti不锈钢在HNO3，H2SO4，H3PO4和HCl溶液中的腐蚀特征，给出了2种不锈钢在酸溶液中的腐蚀速率和不锈钢阀门在酸溶液中的使用寿命。     

Orientation effect of electropolishing characteristics of 316L stainless steel fabricated by laser powder bed fusion

Frontiers of Mechanical Engineering - 3D metal printing process has attracted increasing attention in recent years due to advantages, such as flexibility and rapid prototyping. This study aims to...     

Effect of impact angle on the slurry erosion–corrosion of 304L stainless steel

This communication describes an investigation of the effect of impact angle on slurry erosion–corrosion of stainless steel using a new slurry erosion rig. With the new apparatus, it is possible to measure the individual erosion events under impact as both electrochemical current/time transients, and mechanical transients through acoustic emission (AE) simultaneously. Each sharp rise observed in the electrochemical current transient under particle impact is accompanied by an AE event. These sharp current rises are attributed to the rupture or removal of the oxide film on the surface by the abrasive particles. The correlation between the current rise and the maximum of the AE event, although scattered, shows an increase with decreasing impact angle. The current transients due to individual erosion events show that on the average, the current rise is greater and the rise time is longer at oblique angles compared with those at normal incidence. The degree of denudation of the metal surface by individual particle impingements, the process which strips the surface of its passivity, increases at more oblique angles. Weight loss measurements demonstrate that the synergistic effect between erosion and corrosion is enhanced by a more oblique angle of impact. The origin of the synergism is discussed.     

Effects of laser shock processing on mechanical properties of laser welded ANSI 304 stainless steel joint

With the rapid development of engineering component with integration,high-speed and multi-parameter,traditional techniques haven’t met practical needs in extreme service environment.Laser welding,a new welding technology,has been widely used.However,it would generate the drop of mechanical properties for laser welded joint due to its thermal effect.Laser shock processing(LSP) is one of the most effective methods to improve the mechanical properties of laser welded ANSI 304 stainless steel joint.In this paper,the effects of LSP on the mechanical properties of laser welded ANSI 304 stainless steel joint have been investigated.The welded joint on the front of the tensile samples is treated by LSP impacts,and the overlapping rate of the laser spot is 50%.The tensile test of the laser welded joint with and without LSP impacts is carried out,and the fracture morphology of the tensile samples is analyzed by scanning electron microscope(SEM).Compared with the yield strength of 11.70 kN,the tensile strength of 37.66 kN,the yield-to-tensile strength ratio of 0.310 7,the elongation of 25.20%,the area reduction of 32.68% and the elastic modulus of 13 063.876 MPa,the corresponding values after LSP impacts are 14.25 kN,38.74 kN,0.367 8,26.58%,42.29% and 14 754.394 MPa,respectively.Through LSP impacts,the increasing ratio of the yield strength and tensile strength are 121.79% and 102.87%,respectively;the elongation and area reduction are improved by 5.48% and 29.38%,respectively.By comparing with coarse fracture surface of the welded joint,the delamination splitting with some cracks in the sharp corner of the welded joint and asymmetric dimples,LSP can cause brighter fracture surface,and finer and more uniform dimples.Finally,the schematic illustration of dimple formation with LSP is clearly described.The proposed research ensures that the LSP technology can clearly improve the yield strength,tensile strength,yield-to-tensile strength ratio,elongation,area reduction and elastic modulus of the welded joint.The enhancement mechanism of LSP on laser welded ANSI 304 stainless steel joint is mainly due to the fact that the refined and uniform dimples effectively delay the fracture of laser welded joints.     

Erosion–corrosion and corrosion properties of DLC coated low temperature gas-nitrided austenitic stainless steel

Low temperature nitriding of stainless steel leads to the formation of a surface zone of so-called expanded austenite, i.e. by dissolution of large amounts of nitrogen in solid solution. In the present work the possibility of using nitrogen expanded austenite “layers” obtained by gaseous nitriding of AISI 316 as substrate for DLC coatings are investigated. Corrosion and erosion–corrosion measurements were carried out on low temperature nitrided stainless steel AISI 316 and on low temperature nitrided stainless steel AISI 316 with a top layer of DLC. The combination of DLC and low temperature nitriding dramatically reduces the amount of erosion–corrosion of stainless steel under impingement of particles in a corrosive medium.     

Effect of composition and microstructure on slurry abrasion response of hardfaced martensitic stainless steel

Hardfaced martensitic stainless steel alloy was deposited on mild steel substrate by flux cored arc welding method. The slurry abrasion studies of weld-deposited hardfaced steel were performed using slurry abrasion test rig with 250–300 μm silica sand particles. The effect of weld compositional gradation on the abrasive wear resistance of hardfaced stainless steel at a distance of 0.6, 1.2, 2.4, 3.0 and 3.6 mm from the top surface was studied. The observed abrasion rates were rationalized in terms of mass loss, hardness and distance from the top surface i.e. diluted surfaces beneath the top surface. The abrasive wear mass loss increased with increasing distance beneath the top surface, which was attributed to the coarsening and morphology change in martensite phase. The results of the present work indicated change in morphology of martensite with increase in the distance beneath the top surface. The operating abrasive wear mechanisms involved ploughing, microcutting and indentation.     

Fe24Mn0.5C形变孪晶诱发塑性钢的显微组织和力学性能

采用光学显微镜、X射线衍射仪和电子万能试验机等研究了Fe24Mn0.5C形变孪晶诱发塑性钢的组织和力学性能.结果表明:该钢在室温下为单一的奥氏体组织,拉伸时产生形变孪晶诱发塑性效应,开始产生形变孪晶,并且随着应变量的增加形变孪晶逐渐增加;随着拉伸速度减小,该钢的均匀伸长率呈轻微上升趋势,但屈服强度、抗拉强度和断后伸长率明显升高;与高强度应变诱发塑性590钢相比,该钢具有较高的能量吸收值.     

Ultrastructural effect of self-ligating bracket materials on stainless steel and superelastic NiTi wire surfaces

Frictional interactions between wires and brackets reduce the efficacy in orthodontic treatments. Self‐ligating brackets (SLBs) are now more often used due to lower frictional forces when compared with conventional‐ligating brackets. In this study, scanning electron microscopy and atomic force microscopy were used to examine the microstructural effects of stainless steel and ceramic SLBs on the surface roughness of stainless steel and superelastic NiTi wires both after in vivo clinical orthodontic treatment as well as in in vitro three‐point bending experiments. A combination of two wires—0.019 in. × 0.025 in. stainless steel wires and 0.016 in. superelastic NiTi wires—and two SLBs—both passive‐type stainless steel SLBs and active‐type ceramic SLBs—was applied for 4 months (bicuspid‐extraction) in an in vivo setting and for 1 month in an in vitro setting (200 g loads). After the SLB treatments, all wires exhibited severe scratches secondary to frictional interactions with the brackets. When used with the stainless steel SLBs (Damon 3MX®), the surfaces of 0.019 in. × 0.025 in. stainless steel (P < 0.0001) and 0.016 in. superelastic NiTi wires (P < 0.05) were significantly smoother than when used with the ceramic SLBs (Clippy‐C®). Such results suggest that orthodontic treatments with stainless steel SLBs are more effective than with ceramic SLBs. Microsc. Res. Tech. 75:1076–1083, 2012. © 2012 Wiley Periodicals, Inc.