含钇奥氏体基堆焊焊条堆焊层研究

针对高温、磨损、热疲劳工况下服役零件的失效，研制了一种含稀土元素钇的奥氏体基沉淀强化型堆焊焊条，并对堆焊层组织与性能进行了较系统的研究。     

Mode of deformation and the rate of energy storage during uniaxial tensile deformation of austenitic steel

The mechanism of slip and its consequence in the process of energy storage during uniaxial tension of austenitic steel was studied. The interpretation of the energy storage process in terms of the slip development and microscopic shear band formation is presented.     

A new alloy design concept for austenitic stainless steel with tungsten modification for bipolar plate application in PEMFC

The feasibility of a new alloy design concept utilizing the principle of ‘tungsten bronze effect’ is critically evaluated for the development of metallic bipolar plates for proton exchange membrane fuel cell (PEMFC). An austenitic stainless steel (ASS) is modified with W and La to improve the stability of the passive film in an acidic environment as well as to reduce the contact resistance by the tungsten bronze effect. The experimental ASS containing W and La was evaluated in a simulated PEMFC environment of H₃PO₄ and H₂SO₄ solutions at 80 °C, and the electrical property was evaluated by performing a contact resistance test. The test results show that the ASS modified with W and La has good passive film stability for corrosion resistance and low contact resistance. The X-ray photoelectron spectroscopy (XPS) analysis clearly suggests the possibility of the tungsten bronze effect from the change in valency state of W⁶⁺ to W⁵⁺ in the passive film formed on the modified ASS. The feasibility of a new alloy design concept utilizing the ‘tungsten bronze effect’ is well demonstrated; however, more study is highly required for the development of metallic bipolar plates of PEMFC.     

00Crl8Nil0N奥氏体不锈钢200 - 600℃高温疲劳性能的研究

试验用00Cr18Ni10N钢（/%:0.018C,0.41Si,1.68Mn,18.18Cr,10.38Ni,0.16N）经1t EAF-AOD-ESR冶炼,锻成Φ30 mm材和1 050℃固溶处理,进行了00Cr18Ni10N钢200～600℃光滑（K_t=1）、缺口（K_t=3）的轴向高周疲劳性能研究,绘制了疲劳S-N曲线、计算了疲劳极限,并对疲劳试样的典型断口进行了SEM观察。结果表明,光滑试样的疲劳极限随试验温度升高而降低,缺口试样的疲劳极限对试验温度变化不敏感。当应力集中系数由K_t=1提高到K_t=3时,00Cr18Ni10N钢的200、400、600℃下10⁷周次条件疲劳极限分别从530、506、410 MPa,降低到323、370、392 MPa。表明在高温下00Cr18Ni10N钢存在疲劳极限对应力集中敏感,且应力集中敏感性随着试验温度的升高而降低。疲劳试样的断口形貌由疲劳源区、疲劳裂纹扩展区和瞬断区组成,疲劳起源于表面加工刀痕的不连续位置,呈韧性断裂特征。     

5Cr21Mn9Ni4WNb2N奥氏体耐热钢晶界碳化物

5Cr21Mn_9Ni_4WNb_2N耐热钢锻造后在1200℃以上加热时，NbC聚集成大块，在1200℃以下加热时，NbC薄膜（片）的析出倾向随加热温度降低而增大，1130℃及其以下加热时，粒状和细片状M_(23)C_6随加热温度降低而增多，而且NbC块可作为碳源退化成M_(23)C_6颗粒，过高或过低温度的锻造加热，因晶界NbC块过大或晶界NbC薄膜（片）过多而不利于锻造加工。     

奥氏体不锈钢车削时刀具磨损对切削因素和表面质量的影响研究

研究了奥氏体不锈钢车削加工过程中刀具后刀面磨损对切削力、切削温度、粗糙度及残余应力影响规律。试验结果表明:当刀具后刀面磨损在一定范围内,F_x与F_z随磨损量的增加而显著增大,而F_y基本保持不变;温度随刀具后刀面磨损量增加而显著增大;工件的表面粗糙度随刀具后刀面磨损量增大而增大;当车刀后刀面磨损为0.167 mm时,工件加工表面的残余应力最大。     

Wear mechanisms of PcBN tools when machining AISI 316L

This paper investigates the machinability of AISI 316L stainless steel without and with NMI treatment, when machined with three different PcBN tool grades: low cBN content (50% vol.), medium (65% vol.) and high (90% vol.). The NMI treatment consisted of resulfurized and Ca-treated steels with two different Si/Al ratio. The tool materials were evaluated in terms of tool life, showing the best performance for the medium cBN content grade. Results showed that the crater wear has a more significant effect on the tool performance than the standard wear criteria of maximum flank wear. The worn tools were examined using scanning electron microscopy (SEM), focused ion beam (FIB) and transmission electron microscopy (TEM). In most cases, the crater exhibited three distinct regions from the edge to the end of the contact zone: the plateau, middle crater, and the upper region. Plateau and crater region displayed tool protective layer (TPL), consisting mostly of Al, Si, Mg and Ca-oxides; and some dimples in the tool from preferential wear of cBN grains. In the upper region of the best performing material, a ~1.5 μm thick TPL of mostly MnCr₂O₄ spinel was found, a result of the transfer of Mn- and Cr-rich oxide NMIs found in this material or oxidation of workpiece material, during the machining process.     

Corrosion-resistant analogue of Hadfield steel

The concept of alloying austenitic steels with carbon + nitrogen is used for the development of a corrosion-resistant austenitic CrMn steel having an impact wear resistance close to that of the Hadfield steel. A higher stabilization of the austenitic phase by C + N, as compared to carbon or nitrogen alone, is substantiated by ab initio calculation of the electron structure, measurements of the concentration of free electrons and calculations of the phase equilibrium. Based on these results, the compositions (mass%) Cr18Mn18C0.34N0.61 and Cr18Mn18C0.49N0.58 were melted and tested along with Hadfield steel Mn12C1.2. Mechanical tests have shown that, as compared to the Hadfield steel, the experimental steels possess a higher strength, plasticity, hardness and the same resistance to impact wear. TEM studies of the surface layer after impact treatment revealed a mixture of the amorphous phase, nanocrystals and fine-twinned austenite. At the same time, using Mössbauer spectroscopy of conversion electrons, the ferromagnetic ordering was found in the surface layer of up to 10 μm in depth, which is the sign of the strain-induced martensitic phase. The hypothesis of a transition from the low-spin to the high-spin state of the iron atoms within the thin twins in austenite was proposed in order to interpret the discrepancy between TEM and Mössbauer studies. Potentiodynamic measurements and immersion tests show that the CrMnCN steels possess a significantly higher pitting potential and resistance to general corrosion in comparison with Hadfield steel.     

气压机蒸汽阀波齿垫片爆裂原因分析

经对爆裂的波齿垫片进行宏、微观分析和化学成分分析，认为，爆裂的波齿垫片材料为1Cr18Ni9奥氏体不锈钢，裂纹性质为高频疲劳开裂。由于安装时法兰垫片位置倾斜，而使垫片的外环卡在法兰的凸台处，密封内圈波齿部分未能压紧，在经过10多个小时的吹扫时发生高频振动而开裂，并在高压气条件下发生爆裂。     

In-Situ TEM Tensile Observation of a Metastable Austenitic Manganese Steel

This paper presents the in-situ TEM tensile observation of the nucleation and growth ofmartensite and the dislocation configuration change in metastable austenitic manganesesteels and the investigation of the composition of phases and the content of elements inthe micro regions by XRD,EDAX respectively and concludes from the results that thestrengthening of martensite transformation and high density of dislocations lead to thehigh work-hardening capacity in the steel.