Effect of simultaneous surface modification process on wear resistance of martensitic stainless steel

In order to improve the wear resistance of martensitic stainless steel, a surface treatment system was developed that combines high-frequency induction heating (IH) with fine particle peening (FPP). In this system, a compressed air spray from the FPP nozzle rapidly cools the specimen surface, which is heated by the IH system. The specimen surface can be simultaneously modified by work hardening and quenching. Vickers hardness and retained austenite measurements were conducted to characterize the surface-modified layer generated by the developed process. Surface microstructures were also observed by scanning electron microscopy (SEM) and optical microscopy. The process created a surface with a high hardness and an extremely fine-grained microstructure. The fine-grained microstructure was generated by dynamic recrystallization. The process reduced the amount of retained austenite in the surface layer because it increased the precipitated chromium carbide content. Reciprocating sliding wear tests were conducted to evaluate the wear resistance of the surface. The specimen modified by the developed process exhibited higher wear resistance than specimens that had only been quenched. This implies that the developed simultaneous process can significantly improve the wear resistance of steel surfaces.     

激光相变硬化及激光熔覆技术可提高模具使用寿命

介绍了激光相变硬化及激光熔覆技术的原理、性能及应用实例。     

Enhancing strength-ductility synergy in high-Mn steel by tuning stacking fault energy via precipitation

Deformation-induced twinning or martensitic transformation can improve the work-hardening capabil-ity of alloys with face-centered cubic(FCC)structures and suppress strain localization.The stacking fault energy(SFE)of alloys plays a key role in determining deformation mechanisms and mechanical prop-erties.This study developed V-bearing high-Mn steel with a tensile strength of 1288 MPa and uniform elongation of 36％by tactfully designing the composition.Precipitation of V-carbides was selected to strengthen the steel and tune the global SFE of the matrix by settling carbon.Stronger work-hardening capability due to lower SFE and finer twin/matrix lamellae provided the steel with good ductility,while precipitation strengthened it.     

新型铅酸蓄电池隔板微观结构和宏观性能分析

针对几种新型的铅酸蓄电池隔板（SWP隔板、PG隔板、DE隔板、LP隔板、PE橡胶隔板、PVC-SiO2隔板）的微观结构,做了扫描电镜图,结合扫描电镜图对新型隔板的微观结构及宏观性能进行分析和讨论。以期能正确认识各种隔板的优、缺点,使蓄电池厂家更好地选用合适的隔板。     

40＂末级叶片等离子淬火的工艺开发与生产

大型汽轮机40＂与851mm末级叶片进汽边防水蚀部位淬火带尺寸为270-25mm。本文概述了机械手等离子淬火工艺的特点、工艺试验及批量生产的优良结果与生产业绩。对于汽轮机1000mm类超长末级叶片，等离子淬火防水蚀工艺产生的扭转变形小，相对其它硬化工艺，叶片顺利总装方面更显优势。     

基于朗伯型反射微结构的LED室内照明光源设计

提出了一种基于朗伯型反射面的LED间接照明系统,即LED光源出射的光全部通过朗伯型反射面反射后再照射目标区域,该系统具有光源亮度均匀、灯具效率高等优点,很好地解决了高亮度LED点光源给室内照明带来的眩光问题。首先提出了一种能够很好逼近朗伯反射面的复合型微结构表面,并通过Lighttools光学仿真对其分布参数进行了优化,使最终结果在不同光线入射角的情况下,都具有较理想的余弦反射特性。在此基础上,设计了整体光学系统,使其实现了近180°范围的角度亮度的均匀性和高达84.7%的灯具效率,验证了间接照明方法的可行性。     

应力作用下不锈钢TIG焊焊缝的He+辐照损伤行为

目的 结合核材料应用环境,探究应力作用对304奥氏体不锈钢、430铁素体不锈钢和T91马氏体不锈钢的TIG焊焊缝辐照损伤行为的影响.方法 采用剂量(每cm2的离子数量)为2.1×1017,辐照能量为150 keV,束流为60μA的He+离子束,对2种应力状态下3种不锈钢的焊缝进行He+辐照,并对其辐照前后的微观形貌和显微硬度进行测试分析.结果 SEM图像表明,外加拉应力的引入对304奥氏体不锈钢焊缝辐照缺陷的密度分布和尺寸大小的影响最大,辐照缺陷的间距在有应力作用时缩小了61.5％,缺陷的尺寸则增长了59.2％;纳米压痕数据显示,外加拉应力对T91马氏体不锈钢辐照硬化率增长的影响相对较小,仅为17.9％.结论 应力会使辐照缺陷最大尺寸增加,应力会在一定程度上降低材料的抗辐照性能.辐照导致T91,304,430这3种不锈钢焊缝硬度提高.相同应变条件下,与430不锈钢和304不锈钢相比,T91钢焊缝辐照硬化增量最小,T91焊缝的抗辐照硬化性能相对优异,工程应用中可优先选用T91钢.