Ti-Nb微合金钢中第二相粒子对CGHAZ 组织及韧性的影响

利用碳萃取复型技术研究了含Ti-Nb微合金钢模拟粗晶区(CGHAZ)中的第二相粒子,并利用OM(光镜)、TEM(透射电镜)及系列冲击试验对含Ti-Nb微合金钢CGHAZ的组织及韧性进行了研究.研究结果表明,含Ti-Nb微合金钢中含有大量尺寸细小的TixNb1-x(CyN1-y)粒子,粒子中Nb的相对质量分数(WNb(WNb+WTi))在25%～82%之间,尺寸较大的粒子含有较多Ti,形状接近方形;尺寸较小的粒子含有较多的Nb,形状接近球形.焊接热循环后,粒子的数量显著减少、平均尺寸增大,残留的粒子变为方形.在焊接热循环过程中这些粒子能有效地阻止奥氏体晶粒长大、抑制粗大贝氏体的形成、促进针状铁素体析出及M-A组元的分解,从而显著改善低合金高强钢CGHAZ的韧性,在500～800℃的冷却时间t越长,这种改善作用越明显.     

焊后热处理对30CrMnSiNi2A钢电子束焊接件疲劳行为的影响

电子束局部热处理是一种新型的热处理方式，探讨其对电子束焊接接头组织和疲劳性能的影响规律具有十分重要的实际意义。文中采用CT(紧凑拉伸)试样，对30CrMnSiNi2A钢电子束焊接后焊态、焊后炉内整体热处理和电子束局部热处理三种焊接接头焊缝与母材的疲劳裂纹扩展速率进行试验研究；并测定上述两个部位的门槛值。结合金相组织分析，讨论焊后热处理对接头疲劳行为的影响。试验结果表明，电子束局部热处理和整体热处理都能够在一定程度上改善焊接接头的组织和近门槛值处抗疲劳裂纹扩展的能力。由于电子束局部热处理具有方便、省时、节省能源和提高生产率的优点，因而具有较大的应用潜力和研究价值。     

45钢疲劳损伤的热处理修复机理及其规律研究

通过对45钢疲劳损伤恢复机理及其规律研究,再现疲劳损伤发展过程中的微观组织结构变化,分析了回火温度对疲劳损伤恢复的作用,发现选择回火温度具有“阈值性”。当回火温度与阈值相吻合时,可改变材料的微观结构组态,降低材料的脆性,采用盐浴回火可减少热处理恢复金属材料疲劳[损伤引起的变形,并使45钢的疲劳寿命显著提高。     

热处理对40CrMnSiMoVA超高强度钢腐蚀疲劳裂纹扩展的影响

采用裂纹扩展微机自动测试系统，研究了热处理对４０ＣｒＭｎＳｉＭｏＶＡ（ＧＧ－４）超高强度钢腐蚀疲劳裂纹扩展行为的影响，结果表明，不同热处理时ＧＣ－４钢在３．５％ＮａＣｌ溶液中的ＣＦ裂纹扩展曲线上，都出现了类似于应力腐蚀的平台区，而且随等温温度升高，平台区裂纹扩展速度大大降低，这与材料的显微组织特性有关，研究表明，氢脆在ＧＣ－４钢的腐蚀疲劳中起重要作用。     

不同表面处理对不锈钢SUS304耐微生物腐蚀性能的影响

对焊接的ＳＵＳ３０４不锈钢进行氧化、打磨、酸洗和喷丸等不同处理，研究了不同表面处理对ＳＵＳ３０４不锈钢耐微生物腐蚀性能的影响。在微生物腐蚀试验台中测量了不同表面的试样的开路电压，分析了不同表面处理对电位升的影响。测量了不同表面状态下ＳＵＳ３０４不锈钢的点蚀电位。用俄歇电子能谱（ＡＥＳ）对不同表面进行了分析。得出在不同表面状态下，ＳＵＳ３０４不锈钢耐微生物腐蚀性能由好到差依次是酸洗、喷丸、打磨、原样和氧化。     

双相化对09CuPCrNi耐候钢力学性能的影响

了铁路机车车辆用09CuPCrNi热轧耐候钢,经热处理双相化后的显微组织及力学性能。结果表明：耐候双相钢的显微组织由多边形等轴铁素体晶粒和不规则岛 马氏体组成,其中马氏体含量随淬火加热温度的升高而增加,并且经双相化后无明显的各向异性,双相化加热温度对马氏体含量、屈服现象、屈服强度、抗拉强度、屈强比、伸长率及加工硬化指数（n值）均有显著影响,据此确定了该钢的最佳双相化热处理工艺。     

304不锈钢O形环回弹量的预测模型研究

对304不锈钢多种截面尺寸的O形环短管试样进行多级压扁回弹试验及O形环力学行为的有限元分析.根据量纲分析原理,确定影响回弹量的五个独立变量.发现压缩比在4%至21%之间时压缩比与回弹比及几何构型参量与回弹比之间的线性律,在此基础上提出基于几何效应的TSM-Ⅰ和TSM-Ⅱ回弹量预测模型,由试验结果及有限元结果确定304不锈钢的TSM-Ⅰ和TSM-Ⅱ回弹量预测模型参数,两类模型均有较高预测精度.     

不锈钢焊接接头疲劳强度试验研究

通过焊接接头疲劳试验对SAF2 2 0 5双相不锈钢和 1Cr18Ni9Ti奥氏体不锈钢焊接接头S—N曲线进行详细分析 ,并与 16Mn钢焊接接头的试验结果进行比较 ,讨论不同材料焊接接头及试样接头型式对S—N曲线的影响。试验结果表明 ,SAF2 2 0 5钢和 1Cr18Ni9Ti钢焊接试样的常数m和N =2× 10 6疲劳强度与国际焊接学会 (IIW )推荐的数值有较大差异 ,采用IIW的S—N曲线对本文不锈钢焊接试样疲劳评定时 ,将给出偏于安全的结果 ;接头型式不同导致焊接接头局部应力集中有较大差异 ,因而对采用名义应力表示的S—N曲线有明显影响 ;在同类接头形式下 ,SAF2 2 0 5钢和1Cr18Ni9Ti钢焊接接头的焊态疲劳强度高于 16Mn钢焊接接头 ,而双相不锈钢接头具有更高的疲劳强度     

基于经济流速的管壳式换热器优化设计

基于换热器总费用最低的原则,在初定换热器结构形式后,提出了一种计算最佳流速,进而优化换热器设计的方法。使换热器在比较经济的条件下运动,为企业创造更大的经济效益。     

大型电站用中强钢氢致开裂模式探讨

在低应变速率条件下对不同氢含量的大型电站用中强钢氢致开裂行为进行了研究。结果表明，此类中强钢具有与高强钢不同的氢致开裂模式──随钢中氢含量增加而相继表现出微孔聚合式韧性开裂、变态脆化的微孔聚合式开裂和低能解理式脆性开裂。此模式的主要控制因素为氢在裂尖区域的定向迁移。     

磁处理对低碳钢焊接残余应力作用规律的试验研究

采用正交试验设计的方法系统研究了磁处理对低碳钢焊接试样中残余应力分布的影响,应力测量选用小孔法在20钢焊接试样上进行,比较残余应力在处理前后的变化。试验中考虑三个因素,即磁场方向、磁场强度和处理时间对处理效果的影响。对残余应力的测量结果采用概率统计的方法进行检验,排除了试验误差的干扰,并从中抽取特征量进行正交试验的极差分析。试验和分析结果表明,磁场方向和处理时间是影响磁处理效果的关键因素,并可从中分析得到改变试样中应力分布的最佳处理条件。     

动态应变时效对不锈钢高温强度的影响

本文研究了动态应变时效预处理对18-8型奥氏体不锈钢高温（300～600℃）抗拉强度、疲劳强度和持久强度的影响。结果表明,动态应变时效预处理提高了材料的高温强度,且其强度随预应变温度和预应变量的增加而提高,动态应变时效具有比冷变形处理更优的强化效果。     

400 Mpa超细晶粒钢直流电阻闪光对焊接头组织的数值模拟

对超细晶粒钢直流闪光对焊过程进行了有限元分析.根据计算的焊接温度场和基于EDB模型的Monte Carlo (MC)模拟时间与实际焊接时间的关系,建立了直流闪光对焊过程显微组织的演化模型,对超细晶粒钢筋焊接接头的奥氏体晶粒长大进行了模拟研究,同时考虑了温度梯度对热影响区晶粒长大的热钉轧作用.结果表明,MC模拟技术能预测闪光对焊接头的晶粒大小、尺寸分布,为合理地制定焊接规范、提高接头质量提供有效的分析手段.     

低碳钢表面氩弧硼-碳合金化工艺研究

以氩弧为热源,将含硼、碳的合金粉末熔入低碳钢表面使其合金化。这种方法能快速、便捷地对低碳钢表面进行强化。强化层厚度在2.5-4.0 mm。强化层与基体的结合为冶金结合。获得的强化层中主要强化相是Fe2B和Fe3(B,C)。强化层硬度可达62-67 HRC,并有良好的抗粘着磨损和抗磨料磨损能力。     

THE EFFECT OF DIAMOND PRESSING AND ROLLER BURNISHING OF UNHEAT TREATED CARBON STEEL SURFACES

Diamond pressing (DP) and roller burnishing (RB) processes are surface plastic deformation methods used to improve surface quality (microhardness and surface roughness). In the present work DP and RB tools with a special holder were used to study the effect of DP and RB on the surface texture of three different carbon steels (low, medium, and high) and to compare the both methods. The results show that the RB in the case of low carbon steel is better than the DP in terms of its effect on the microhardness and surface roughness, but in the case of the medium and high carbon steel the results depicts that the DP is better than RB in terms of its effect on the microhardness, but the RB is better than DP in terms of its effect on the surface roughness. As a result of this study it was found that DP and RB have a great effect on surface texture and RB was found to be better in surface roughness, but DP has better results in surface microhardness relative to ground surfaces. Also in this paper micrographs of the processed surfaces of low, medium and high carbon steel are given and it is shown that the depth of plastic deformed surfaces by diamond pressing was about (330, 345, 390) µm and by roller burnishing about (270, 245, 230) µm for the three steels, respectively.     

钢丝绳结构及工艺集成设计系统

针对钢丝绳实际生产需要,提出基于钢丝绳结构理论设计基础的结构与工艺集成设计系统框架,建立钢丝绳结构设计、性能分析及间隙计算的理论模型,并利用相关数据进行理论值与实际值分析,完成钢丝绳性能参数的敏感性分析模型和理论修正模型,为钢丝绳结构设计与工艺设计的并行处理提供了理论上的指导,最终实现钢丝绳的智能设计与制造。     

THE EFFECT OF DIAMOND PRESSING AND ROLLER BURNISHING OF UNHEAT TREATED CARBON STEEL SURFACES

Diamond pressing (DP) and roller burnishing (RB) processes are surface plastic deformation methods used to improve surface quality (microhardness and surface roughness). In the present work DP and RB tools with a special holder were used to study the effect of DP and RB on the surface texture of three different carbon steels (low, medium, and high) and to compare the both methods. The results show that the RB in the case of low carbon steel is better than the DP in terms of its effect on the microhardness and surface roughness, but in the case of the medium and high carbon steel the results depicts that the DP is better than RB in terms of its effect on the microhardness, but the RB is better than DP in terms of its effect on the surface roughness. As a result of this study it was found that DP and RB have a great effect on surface texture and RB was found to be better in surface roughness, but DP has better results in surface microhardness relative to ground surfaces. Also in this paper micrographs of the processed surfaces of low, medium and high carbon steel are given and it is shown that the depth of plastic deformed surfaces by diamond pressing was about (330, 345, 390) µm and by roller burnishing about (270, 245, 230) µm for the three steels, respectively.     

新型热作模具钢CH95的热稳定性能研究

从热作模具钢在６５０℃和７００℃时效过程中的硬度变化和组织变化来探讨其热稳定性能。研究结果表明，新型热作模具钢ＣＨ９５钢的热稳定性能明显优于Ｈ１１。     

IMPROVEMENTS IN THE SURFACE CHARACTERISTICS OF STAINLESS STEEL WORKPIECES BY BURNISHING WITH AN AMORPHOUS DIAMOND-COATED TIP

Burnishing is a cold working process that can be used to improve surface finish and surface hardness of workpieces. Conventionally, diamond or hard metal burnishing tools are used. In the present work, a novel burnishing tool was created by depositing amorphous diamond coating (AD) on a stainless steel tip. This tool was used to improve the surface finish and surface hardness of Nitronic-50 HS stainless steel workpieces. Nitronic-50 HS is used in a wide range of applications in industry. The burnishing process was carried out at different burnishing parameters (force, revolution speed, feed and number of tool passes). Burnishing parameters had a significant effect on the finishing process and they had to be optimized to achieve the best results. Remarkable improvements in surface finish (70% decrease in roughness) and hardness (25% increase) could be achieved with this tool and process in the surface finishing of Nitronic-50 stainless steel workpieces. From the tribological point of view, the AD-coated tip performed slightly better than a corresponding tip modified from a commercial polycrystalline diamond tip. AD coating seems to be very suitable for use in mechanical surface finishing tools such as a burnishing tip.     

局部焊后热处理两类评定准则的研究

焊后热处理的主要目的有 2个 :其一是消除焊接残余应力 ;其二是改善焊接接头的性能 ,因此焊后热处理的评定也应同时考虑这 2个方面。局部焊后热处理通常用于炉内整体热处理无法应用的场合。然而至今各国关于局部焊后热处理的评定标准仍存在很大的差异。采用考虑高温蠕变的粘弹塑性有限元等数值方法与试验相结合 ,对具有初始焊接残余应力的管子在不同热处理条件下进行了系列分析 ,特别是对于局部焊后热处理加热宽度的确定进行了大量研究。基于上述研究提出了 2个局部焊后热处理的评定准则 ,即基于残余应力消除效果的残余应力准则和基于改善焊接接头性能的均热区温差准则。局部焊后热处理应同时满足这两个准则的条件。