Effect of heat treatment on microstructure and mechanical properties of Ti-containing low alloy martensitic wear-resistant steel

Effects of quenching temperature and cooling conditions(water cooling and 10%NaCl cooling)on microstructure and mechanical properties of a 0.2%Ti low alloy martensitic wear-resistant steel used for die casting ejector plate were investigated.The results show that lath martensite can be obtained after austenitizing in the range of 860-980℃and then water cooling.With an increase in austenitizing temperature,the precipitate content gradually decreases.The precipitates are mainly composed of TiC and Ti4C2S2,and their total content is between 1.15wt.%and 1.64wt.%.The precipitate phase concentration by water-cooling is higher than that by10%NaCl cooling due to the lower cooling rate of water cooling.As the austeniting temperature increases,the hardness and tensile strength of both water cooled and 10%NaCl cooled steels firstly increase and then decrease.The experimental steel exhibits the best comprehensive mechanical properties after being austenitized at 900℃,cooled by 10%NaCl,and then tempered at 200℃.Its hardness,ultimate tensile strength,and wear rate reach551.4 HBW,1,438.2 MPa,and 0.48×10^(-2)mg·m^(-1),respectively.

Microstructures and wear-resistant properties of in-situ TiC_p/ZA-12 composites

TiC_p/ZA-12 composites were fabricated by exothermic disposition method process and stirring-casting techniques. The microstructure and wear-resistant properties were investigated . The results show that TiC particles are formed in-situ and distributed uniformly in matrix. No particles aggregation and macro or micro precipitation are observed. The wear-resistant properties of composites increase with the increase of TiC_p content, but will not increase when the TiC_p content reaches constant value. Finally, the friction and wear mechanism were also discussed.

Effects of air-atomized water spray cooling device structure on the quenching process,microstructure,and properties of wear-resistant steel

With its high strength and hardness, wear-resistant steel has become an important material in the field of construction machinery manufacturing.Given that quenching technology is a crucial component of wear-resistant steel production, the selection of the cooling method to be used during this process is important.In this study, the feasibility of quenching wear-resistant steel by air-atomized water spray cooling was studied, and the cooling rate, microstructure, and hardness of wear-resistant steel under various cooling device structures were analyzed.The results reveal that the air-atomized water spray cooling method is an effective technique in quenching wear-resistant steel.Furthermore, martensite and uniform hardness were obtained by the air-atomized water spray cooling technique.As the space between the nozzles in each row in the device increased, the cooling rate was reduced during quenching.Meanwhile, the martensite content decreased, and more carbides were observed in the martensitic structure.A mixture comprising self-tempered martensite and bainite was formed at a large distance over a longer period of time.All these factors resulted in lower hardness and worse property uniformity.

Numerical simulation of temperature field in laser-arc hybrid welding of wear-resistant steel

Using ABAQUS software and cylindrical ellipsoid and body heat sources with a peak-heat-flux- attenuation function, a finite element model of the temperature field in the laser-arc hybrid welding of 4.5-mm BW300TP wear-resistant steel is proposed. The proposed model considers convection, radiation, molten pool flow, and heat conduction effect on temperature. A comparison of the simulation and actual welding test results confirms the reliability of the model. This welding heat-process model can provide the cooling rate at any position in the heat affected zone （HAZ） and can be used as a reference for the analysis of material properties and for process optimization.

Hot cracking susceptibility research in BTW1 austenitic high-manganese wear-resistant steel

Baosteel’s first BTW1 austenitic high-manganese wear-resistant steel exhibits strong deformation-induced hardening characteristics.Compared with common low-alloy martensitic wear-resistant steels in the market, it has improved impact wear resistance, hard abrasive wear, erosion wear performance, and impact toughness.The metallurgical properties of such austenitic wear-resistant steel lead to the risk of failure because of hot cracking defects in the welded structure.In wear-resistant applications, evaluating hot cracking susceptibility is necessary to avoid the effect of welding defects.In this study, the Varestraint test is used to quantitatively analyze and evaluate the hot cracking susceptibility of BTW1 austenitic high-manganese wear-resistant steel.The test results show that by controlling the content of impurity elements and grain refinement, BTW1 austenitic high-manganese wear-resistant steel effectively reduces hot cracking tendency and has a low incidence of hot cracking under small strain conditions.The developed matching welding process can effectively avoid the influence of hot cracking susceptibility.

Developing Maanshan Kuangyou Wear-resistant Materials Group Company

Maanshan KuangyouGroup company is a special largeenterprise making wear-resistantmaterials products,integratingscience,industry and trade.Mainproducts are chromium-contentwear-resistant materials and ship-use anchor chains."Kuangyou"Brand balls have been awardedprizes of Quality Products by theprovince and ministry,and prizeof Scientific Progress by theprovince,and are widely appliedin mining,cement,power andchemicals industries.Ship-useanchor chains have an

Wear-resisting Oxide Films for 900℃

A study was conducted to develop low-friction, wear-resistant surfaces on high temperature alloys for the temperature range from 26℃ to 900℃. The approach investigated consists of modifying the naturally occurring oxide film in order to improve its tribological properties. Improvement is needed at low temperatures where the oxide film, previously formed at high temperature, spalls due to stresses induced by sliding. Experiments with Ti, W and Ta additions show a beneficial effect when added to Ni and Ni-base alloys. Low friction can be maintained down to 100℃ from 900℃. For unalloyed Ni friction and surface damage increases at 400℃ to 500℃. Two new alloys were perpared based on the beneficial results of binary alloys and ZrO2 diffusion in Ni.Low friction at temperature above 500℃ and reasonable values (0.32~0.42) at low temperature are obtained.

MICROSTRUCTURES OF A NOVEL HIGH STRENGTH AND WEAR-RESISTING ZINC ALLOY

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Elements inter-diffusion in the turning of wear-resistance aluminum bronze

Inter-diffusion of elements between the tool and the workpiece during theturning of aluminum bronze using high-speed steel and cemented carbide tools have been studied. Thetool wear samples were prepared by using M2 high-speed steel and YW1 cemented carbide tools to turna novel high strength, wear-resistance aluminum bronze without coolant and lubricant. Adhesion ofworkpiece materials was found on all tools' surface. The diffusion couples made of tool materialsand aluminum bronze were prepared to simulate the inter-diffusion during the machining. The resultsobtained from tool wear samples were compared with those obtained from diffusion couples. Stronginter-diffusion between the tool materials and the aluminum bronze was observed in all samples. Itis concluded mat diffusion plays a significant role in the tool wear mechanism.

Effect of Rare Earths-Treated Glass Fiber on Impact Wear-Resistance of Metal-Plastic Multilayer Composites

The friction and wear properties under impact load and dry friction conditions of metal-plastic multilayer composites filled with glass fiber, treated with rare earth elements, were investigated. The worn surfaces were observed and analyzed by scanning electron microscopy (SEM). It shows that applying rare earth elements surface modifier to treat the glass fiber surface can enhance the interfacial adhesion between the glass fiber and polytetrafluoroethylene (PTFE), as well as promote the interface properties of the composites. This helps to form a uniformly distributed and high adhesive transfer film on the counterface and abate the friction between the composite and the counterface. As a result, the wear of composite is greatly reduced. The composite exhibits excellent friction properties and impact wear-resistance.

Wear-resistance Performance of Spray-welding Coating by Plasma Weld-surfacing

Alloy powders including Ni60, WC, CrC, and TiC with different mass ratios were deposited on medium carbon low alloy steel by plasma welding. Through the experiments, the optimal alloy powder reinforcing cutter tool surface properties were discovered. The wear resistance properties were investigated on the impact abrasive wear tester. The experimental results show that in terms of microstructure, there exists the shape of herringbone, spider mesh, broken flower structures in coatings. In addition, fusion area of four specimens surfacing welding layer displays a large number of acicular martensite with a small amount of austenite. The coating mainly consists of Ni-Cr-Fe austenitic phase and the other precipitates. TiC density is smaller, its content is less in alloy powder, in the process of surfacing welding, TiC is melted fully, which is mainly distributed in surface layer and middle layer of hard facing layer. The content of TiC gradually reduces from surface layer of hard facing layer to the fusion area. Compared to TiC, the density of tungsten carbide and chromium carbide is larger, there exist tungsten carbide and chromium carbide particles, which are not completely melted near the fusion area. The micro-hardness presents gradient change from the fusion area to the surface layer of hard facing layer, and the hardness of the middle layer is slightly lower than that of the fusion area, and the hardness increases near the surface layer.

To a forecasting of the wear-resistance of friction units details parameters question

The process of wear process expedient considering as set of special cases wear. For each special case wear were received settlement with reference to some certain conditions of experimental researches realisation, uniting in self SLOP. For successful application deduced dependence at forecasting wear-resistance the mechanism of reduction is developed which allows to distribute deduced dependencies to any conditions of wear process.

不同电流下的电弧侵蚀对浸铜碳滑板/铬锆铜接触线磨损机理的影响

弓网之间由于短时间离线容易产生电弧,离线电弧会严重灼伤碳滑板和接触线表面,导致碳滑板服役寿命衰减和过早老化.采用了不同强度电流形成的电弧对碳滑板表面进行侵蚀处理,发现随着电流的强度增加,接触区域的离线电弧能量冲击强度和瞬时温度逐渐提升.受电弧侵蚀之后Cu从碳滑板基体中大量析出并熔焊成瘤状物,在侵蚀区域形成不规则疏松层和扩展裂纹.接着对碳滑板进行载流摩擦磨损试验,结果表明摩擦系数和接触电阻均随着侵蚀时间的增加而增大.通过扫描电镜和三维形貌测试分析方法,揭示了经电弧侵蚀之后碳滑板/接触线的载流摩擦磨损机理和性能差异,其主要磨损机制为磨粒磨损和氧化磨损.

履带浮筒式挖藕机滑橇支承装置设计与试验

针对履带挖藕机行驶阻力大和下陷深的问题,该研究设计了一种滑橇支承装置,该装置安装于底盘两侧,由液压驱动其上下运动调节所在位置,可辅助支撑底盘,从而降低履带接地压力和下陷深度以改善通过性。为明确增加滑橇支承装置后底盘行驶性能的变化,以履带浮筒式挖藕机底盘为对象,建立底盘行驶阻力和牵引力模型,对土壤与滑橇前端破土面间的挤压受力进行理论分析。以前进阻力为指标,建立原尺寸三分之一的滑撬比例模型,利用EDEM软件开展单因素仿真试验,获得滑切角、斜切角、行进速度和下陷深度对前进阻力的影响规律。以滑切角、斜切角、行进速度为影响因素开展Box-Behnken中心组合试验,结果表明,滑切角40°、斜切角70°、行进速度0.1 m/s时前进阻力最小,仿真模拟与台架试验结果分别为66.09和82.28 N。开展采用滑撬支承装置前后的履带浮筒式挖藕机田间行驶性能对比试验,结果显示,采用滑撬支承装置前后行驶马达阻力矩降低6.51%,底盘下陷深度降低7.64%,整机通过性得到提高。研究结果可为水田地面机器系统行走装置设计及其工作机理研究提供参考。

滑板底盘概述以及发展趋势

介绍了滑板底盘的基本概念,技术上的主要特点,以及商业化方面的主要挑战。继而针对性阐述了相应的商业化可能的解决方案,并结合最新车企的动向,展望了该技术即将大规模地商业化落地的前景以及良好发展趋势。

滑板运动员的合理膳食研究

滑板运动是一项集挑战性、观赏性和刺激性于一体的技巧性新兴运动,该运动极度考验运动员的身体平衡能力、灵敏性、协调性和反应能力,对合理膳食和营养摄入的要求较高。本文深入探讨滑板运动员在营养膳食方面的具体需求,进而为滑板运动员提供一系列科学合理的膳食建议,以满足滑板运动员在训练和比赛中的营养需求,提高滑板运动员的竞技能力和健康水平。

转炉滑板挡渣技术的现场应用实践

本文从转炉滑板挡渣机械原理进行分析,通过现场工业试验并结合生产实践,对转炉滑板挡渣机构形变数据进行了统计和分析确定合理的形变技术范围,为滑板弹簧离线维护工作量的减少和滑板板间穿钢频次降低提供了技术支撑;同时对滑板维护操作规范进行优化,进一步降低钢包回磷发生频次,对比分析得出滑板挡渣技术在转炉上的成功率高、挡渣效果好,转炉挡渣率可控制在99.5%以上,为转炉生产高端品种钢提供质量保证。对国内各钢铁企业准备投入使用转炉滑板挡渣法具有很好的推广价值。

基于SSM框架的受电弓碳滑板温测系统的设计与开发

本文基于SSM框架设计开发受电弓碳滑板的温度监测系统,系统主要功能包括温度数据的接收存储和显示、产品的质量管理、碳滑板材料的管理、用户管理和异常报警模块,数据接收模块包含温度数据、时序信息、配置参数,温度数据存储于MySQL的数据库,平台以曲线图和柱形图形式直观展示下位机采集的温度数据。通过监测受电弓如碳滑板的温度,可评估弓网接触压力是否适中、滑板磨损是否均匀、接触电阻是否过大的问题,根据温度数据可适时调整受电弓工作参数或进行维护干预,确保受电弓在最佳状态下运行,进而提高电力传输效率、减少能源损耗,对保障铁路电力牵引系统的安全高效运行有至关重要的意义。

动车组受电弓碳滑板厚度检测算法研究

弓网系统对电气化铁路的提速和安全运行至关重要,传统的人工测量碳滑板厚度存在工作效率低、检修周期长问题。首先,对现场采集的碳滑板图片进行灰度处理、透视校正、图像滤波、图像增强;其次,提出一种基于canny算子的边缘检测算法对碳滑板边缘提取和定位;最终,得到碳滑板厚度曲线。实验结果表明,通过图像检测算法测量得到的碳滑板厚度值误差在合理范围内,准确度高,具有实际的工程应用价值。

一种基于光纤测温的碳滑板温度监测和控制系统设计

在高速铁路与城市轨道交通系统中,随着列车运行速度的提升及运行环境的复杂多变化,碳滑板在高电压、大电流工况下易因温度过高而导致磨损加速、性能衰退乃至失效,严重影响列车的运行效率与安全。因此,对碳板温度进行实时、准确的监测与控制成为保障轨道交通安全高效运营的重要课题。该文的核心是开展光纤温度传感器的系统开发,研究终端荧光测温节点与配套的无线监控硬件架构,此架构涵盖了从电源管理、测温警报机制、串口通信接口到无线网络传输等关键电路模块的设计,确保了从荧光信号捕捉至数据发送端与接收端的顺畅运作,为轨道交通的智能化与安全保障水平提升奠定了坚实的理论基础与技术支持。