碳素股骨头奥氏体不锈钢柄的研制及应力测试

为推广应用兰州碳素厂生产的人工碳素股骨头,1984年我们承担了碳素股骨头的奥氏体不锈钢柄的研制任务。在原上海Ⅰ型股骨头柄的基础上进行了修改。在柄插入头的轴部钻三排纵孔,将柄上部内外侧面横形加宽1～4 mm;使柄的轴和干部直角改成曲线角;再将奥氏体不锈钢柄作了应力测试和动物埋置试验,动物实验结果满意;测试证明改良的金属柄适宜于生物力学结构。1986年我们将这种新型碳钢组合股骨头应用于临床。

铁素体奥氏体型双相不锈钢的侵蚀方法

在GB/T 6401-1986所提供的侵蚀铁素体奥氏体型双相不锈钢方法的基础上,开发了一种新的侵蚀方法,与GB/T 6401-1986中的侵蚀方法相比,该方法具有操作简便、两相衬度及轮廓线清晰等优点。

奥氏体不锈钢焊缝超声相控阵检测图像智能分类

奥氏不锈钢焊缝的粗晶粒以及材料各向异性,导致超声检测图像信噪比较低,人工检测判断缺陷存在困难。分别使用InceptionV3、ResNet50、DenseNet121和MobileNetV2卷积神经网络来进行奥氏不锈钢焊缝相控阵B扫图像的自动分类。实验结果表明,大型卷积神经网络分类准确率高,ResNet50和DenseNet121在测试集上的分类准确度达到100%,Inception V3达99.8%,但轻量化的卷积神经网络MobileNetV2的准确率只有90.8%,存在严重过拟合。通过改进轻量化卷积神经网络MobileNetV2的训练方式,并引入Dropout层,可以保证分类准确度达到100%,并且减小了大量网络参数,更利于移动端的应用。

循环荷载下奥氏体型和双相型不锈钢材料本构关系研究

为研究循环荷载下不锈钢材料的本构关系,对奥氏体型S30408不锈钢和双相型S220503不锈钢材料进行了单调拉伸和大应变超低周循环加载试验。采用三种常用的单调拉伸本构模型对所得应力-应变曲线进行拟合,得到相应单调荷载下材料本构参数;采用Ramberg-Osgood本构模型对循环骨架曲线进行拟合,得到材料循环强化参数;利用Chaboche塑性本构模型,标定了两种材料的循环本构参数。结果表明:在单调拉伸荷载下,G-R-O本构模型更适用于拟合不锈钢材料的单调拉伸本构;在循环荷载下,不锈钢材料滞回曲线饱满,且随着应变增大,两种材料在加载后期均表现出了明显的循环强化现象;Ramberg-Osgood本构模型对骨架曲线拟合较好,有限元计算结果和试验滞回曲线吻合度高;表明该文标定出的强化参数、循环本构参数可用于结构体系地震响应分析之中,为准确分析不锈钢结构在地震作用下的受力性能提供参考。

热处理工艺对奥氏体型不锈钢中铁素体相的影响

在不同的加热温度、保温时间下,分析铁素体相在钢锭截面上的分布状况及铁素体相的数量和形态的变化规律,制定奥氏体型不锈钢热加工工艺。

高Cr奥氏体型不锈钢气体保护焊用焊接材料

针对国内外火力发电厂中高温高压工作环境的要求,研发了高Cr奥氏体型不锈钢焊接材料,并对其工艺性能进行了研究。

室内消火栓阀杆采用奥氏体型不锈钢棒代替铅黄铜棒的可行性探讨

从耐腐蚀的不锈钢金属材料中选用市场上较常见、较典型的奥氏体型不锈钢和马氏体型不锈钢制成室内消火栓的阀杆,分别从耐腐蚀性能、力学性能、使用性能、加工工艺、生产成本以及产品监督检查等方面与铅黄铜棒进行比较,全面探讨室内消火栓阀杆采用奥氏体型不锈钢棒替代铅黄铜棒的可行性。

仪表常用不锈钢牌号及性能

针对不锈钢的种类繁多,其特性、用途各有不同,中外命名方式也不同,容易给使用者带来混淆的问题,对仪表范畴内常用不锈钢的金相分类、金相结构、机械性能、耐腐蚀性能、牌号等内容进行了归类整理,重点针对300系列奥氏体不锈钢的成分组成、用途、机械特性、特性演变等进行了论述。另对不锈钢国家标准中新旧牌号、常用不锈钢中外牌号进行了对比说明和比较,针对美国铸造/锻造标准牌号区别、含义、材料的温度-压力特性及注意事项等方面进行了介绍。

不锈钢套装油管路工艺攻关

系统地介绍了汽轮机不锈钢套装油管路结构特点、技术难点和制造工艺方案，以及在制造工艺中所采用的新技术、新方法，对不锈钢产品，尤其是不锈钢管道的制造有一定的参考和指导价值。

奥氏体型S30408不锈钢角焊缝连接拉伸试验研究

为研究奥氏体型S30408不锈钢角焊缝连接接头的承载性能,对6个正面角焊缝连接试件和5个侧面角焊缝连接试件进行了拉伸试验,测得焊缝连接试件在拉伸作用下的极限荷载,以及焊缝强度、焊缝随荷载的变形情况,并对焊缝的破坏状态进行了观察。试验结果表明:正面角焊缝连接接头焊缝断裂面呈底部垂直于芯板表面而上部接近30°斜截面的不规则撕裂状,其抗拉强度平均值742 MPa,焊缝平均变形量为2.875 mm。侧面角焊缝连接接头焊缝断裂面较为平整,接近45°理论值,其剪切强度平均为506 MPa,焊缝平均变形量为4.387 mm。正面角焊缝连接试件焊缝抗拉强度为侧面角焊缝连接试件剪切强度的1.47倍。正面角焊缝和侧面角焊缝连接试件承载力试验值均高于CECS 410:2015《不锈钢结构技术规程》和欧洲规范Eurocode 3的设计值,CECS 410:2015规程中对于正面角焊缝和侧面角焊缝连接试件承载力设计值的规定过于保守;欧洲规范Eurocode 3对正面角焊缝连接试件承载力设计值的规定也较为保守,而对侧面角焊缝连接试件承载力设计值的规定较为合理。

低镍奥氏体不锈钢冷轧边裂原因分析

针对低镍Cr-Mn-Ni-N奥氏体不锈钢冷连轧过程中的边裂问题,采用金相显微镜、扫描电子显微镜分析了断口、边裂位置附近、正常位置显微形貌;分析了冷轧带钢横向应力、轧制力分布规律。结果表明,钢中镍元素偏析、存在Al2O3夹杂物、形变马氏体组织含量增加,以及带钢边部应力、轧制力较大,是导致低镍奥氏体不锈钢冷连轧过程出现边裂,甚至导致断带的主要原因。为此,提出了连铸冷却模式采用弱冷;在热连轧铸坯加热及后工序带钢固溶退火工艺中对材料合金元素进行均质化处理;优化冷连轧工艺,保证第1道次压下率为30%~35%,总压下率为50%~68%,使马氏体形变组织得到有效控制;保证原料楔形、板凸度等在合理范围内,并通过调整弯辊力来改善轧制力的横向分布等措施,使带钢轧后边裂断带率由0.98%降至0.25%。

Prediction of Hot Deformation Behavior of 7Mo Super Austenitic Stainless Steel Based on Back Propagation Neural Network

The hot compression tests of 7Mo super austenitic stainless(SASS)were conducted to obtain flow curves at the temperature of 1000-1200℃and strain rate of 0.001 s^(-1)to 1 s^(-1).To predict the non-linear hot deformation behaviors of the steel,back propagation-artificial neural network(BP-ANN)with 16×8×8 hidden layer neurons was proposed.The predictability of the ANN model is evaluated according to the distribution of mean absolute error(MAE)and relative error.The relative error of 85%data for the BP-ANN model is among±5%while only 42.5%data predicted by the Arrhenius constitutive equation is in this range.Especially,at high strain rate and low temperature,the MAE of the ANN model is 2.49%,which has decreases for 18.78%,compared with conventional Arrhenius constitutive equation.

THRESHOLD STRESS INTENSITIES FOR HYDROGEN-INDUCED DELAYED FAILURE OF WELD METAL OF AUSTENITIC STAINLESS STEEL

It was found that hydrogen induced delayed failure could occur in 308L and 347L weld metals,and the threshold stress intensities of 308L and 347L welds were lower than that of 304L austenitic stainless steel.When dynamically charged under load on a single edge notched specimen,the threshold stress intensities of 308L,347L and 304L decrease with the increase in the diffusible hydrogen content C 0 and the experimental results are as follows:K ⅠH =85.2-10.7 ln C 0 (308L),K ⅠH =76.1-9.3 ln C 0 (347L),K ⅠH =91.7-10.1 ln C 0 (304L).The morphology of the hydrogen induced delayed fracture in the three materials are correlated with the K Ⅰ and C 0 values.

超高压锅炉异种钢管焊接工艺制订原则

阐述了奥氏体不锈钢与低合金钢异种接头的焊接性和焊接工艺性，分析了异种钢焊缝焊接工艺制定的原则，认为选用镍基材料作为焊接材料并采用适当的工艺措施可保证焊缝质量及延长异种钢接头的寿命。

Application of response surface methodology to maximize tensile strength and minimize interface hardness of friction welded dissimilar joints of austenitic stainless steel and copper alloy

An attempt was made to optimize friction welding parameters to attain a minimum hardness at the interface and a maximum tensile strength of the dissimilar joints of AISI 304 austenitic stainless steel （ASS） and copper （Cu） alloy using response surface methodology （RSM）. Three-factor, five-level central composite design matrix was used to specify experimental conditions. Twenty joints were fabricated using ASS and Cu alloy. Tensile strength and interface hardness were measured experimentally. Analysis of variance （ANOVA） method was used to find out significant main and interaction parameters and empirical relationships were developed using regression analysis. The friction welding parameters were optimized by constructing response graphs and contour plots using design expert software. The developed empirical relationships can be effectively used to predict tensile strength and interface hardness of friction welded ASS-Cu joints at 95% confidence level. The developed contour plots can be used to attain required level of optimum conditions to join ASS-Cu alloy by friction welding process.

Effect of low-frequency rotary electromagnetic-field on solidification structure of continuous casting austenitic stainless steel

To understand the solidification behavior of austenitic stainless steel in rotary electromagnetic-field, the influence of low-frequency rotary electromagnetic-field on solidification structure of austenitic stainless steel in horizontal continuous casting was investigated based on industrial experiments. The results show that the solidification structure of austenitic stainless steel can be remarkably refined, the central porosity and shrinkage cavity can be remarkably decreased, and the equiaxed grains zone are enlarged by means of application of appropriate low-frequency electromagnetic-field parameters. The industrial trials verify that the stirring intensity of austenitic stainless steel should be higher compared with that of plain carbon steel. Electromagnetic stirring affects the macrostructure even if the average magnetic flux density of the electromagnetic stirring reaches 90 mT (amplitude reaches 141 mT) with the frequency of 3-4 Hz. Due to a higher viscosity, rotating speed of molten stainless steel is 20%-30% lower than that of molten carbon steel in the same magnetic flux density.

Effect of aging treatment on irradiation-induced segregation of high Mn-Cr steel

To investigate the effect of aging treatment on irradiation-induced segregation of high Mn-Cr steel, specimens for electron-beam irradiation were prepared from the high Mn-Cr austenitic steel which was solution treated at 1 373 K for 1 h and aging treated at 573 K for 1 000 h, respectively. The electron-beam irradiation was performed at 573 K up to doses of 5.4 dpa in a 1 250 kV HVEM and irradiation-induced segregation analyses were carried out by an EDX in a 200 kV FE-TEM. The results show that void formation is not observed in both solution treated and aging treated ones. The amount of Cr segregation at the grain boundary decreases in the aged one; however, that of Mn is not changed in solution treated one.

Activated flux tungsten inert gas welding of 8 mm-thick AISI 304 austenitic stainless steel

AISI 304 stainless steel plates were welded with activated flux tungsten inert gas(A-TIG) method by utilizing self-developed activated flux. It is indicated from the experimental results that for 8 mm-thick AISI 304 stainless steel plate, weld joint of full penetration and one-side welding with good weld appearance can be obtained in a single pass without groove preparation by utilizing A-TIG welding. Moreover, activated flux powders do not cause significant effect on the microstructure of TIG weld and the mechanical properties of A-TIG weld joints are also superior to those of C-TIG(conventional TIG) welding.

Influence of chemical composition and cold deformation on aging precipitation behavior of high nitrogen austenitic stainless steels

The influence of chemical composition and cold deformation on aging precipitation behavior of 18Cr-16Mn-2Mo-I.IN （HNS-A）, 18Cr-16Mn-I.3N （HNS-B）, 18Cr-18Mn-2Mo-0.96N （HNS-C） and 18Cr-18Mn-2Mo-0.77N （I-INS-D） high nitrogen austenitic stainless steels was investigated. The results show that the ＂nose＂ temperatures and incubation periods of the initial time-temperature-precipitation （TTP） curves of aged HNSs are found to be 850 ℃, 60 s; 850 ℃, 45 s; 850 ℃, 60 s and 900 ℃, 90 s, respectively. Based on the analysis of SAD patterns, the coarse cellular Cr2N precipitate which presents a lamellar structure has a hexagonal structure of a=0.478 nm and c=0.444 nm. The Z phase corresponding to a composition of Fe36Cr^2Mo10, is determined to be a body-centered cubic structure ofa=0.892 nm. The precipitating sensitivity presents no more difference with the nitrogen content increasing from 0.77% to 0.96%, but exhibits so obviously that the cellular precipitates nearly overspread the whole field. The addition of Mo element can restrain the TTP curves moving left and down, which means decreasing the sensitivity of aging precipitation. With increasing the cold deformation, the sensitivity of precipitation increases obviously.

Effect of Radial Depth on Vibration and Surface Roughness During Face Milling of Austenitic Stainless Steel

This paper studies the influence of radial depth on vibration, chip formation and surface roughness during face milling of AISl3O4 austenitic stainless steel with indexable cemented carbide milling cutters. The amplitude of vibration acceleration increased with the increasing radial depth up to 80 mm. And the domain vibration frequency varied with the radial depth. In this paper, three types of chips were found： C shape, long shape and spiral shape. The minimum surface roughness value occurred when the radial depth equalled 40 mm in the experiment. Irregular changes of chip curl radius and chip thickness could be attributed to different numbers of alternately engaged teeth when the feed and speed were fixed. Surface roughness is related to forced vibration and chip formation. Radial depth with different numbers of alternately engaged teeth could significantly influence the forced vibration, chip formation, and surface roughness.