提高塑料模具使用寿命的表面强化技术

从表面淬火、表面扩散化学热处理和表面覆层强化三方面介绍了提高塑料模具使用寿命的表面强化技术。指出正确运用表面强化技术是提高塑料模具使用寿命的一个行之有效的途径,具有事半功倍之效。     

提高塑料模具使用寿命的表面强化技术

从表面淬火、表面扩散化学热处理和表面覆层强化三方面介绍了提高塑料模具使用寿命的表面强化技术。指出正确运用表面强化是提高塑料模具使用寿命的一个行之有效的途径,具有事半功倍之效。     

塑料模具的表面强化技术

本文介绍了从塑料模具表面强化技术开发方面综述了国内在提高塑料模具寿命研究方面的进展。其中化学镀、电刷镀可显著提高塑料模具的使用寿命。     

塑料模具的表面强化技术

本文介绍了从塑料模具表面强化技术开发方面综述了国内在提高塑料模具寿命研究方面的进展。其中化学镀、电刷镀可显著提高塑料模具的使用寿命 。     

塑料模具的表面强化技术

简要评述了塑料模具型腔面的工作条件及其失效形式，指出了正确运用表面强化技术大幅度提高模具使用寿命、以普通模具钢取代优质模具钢拓宽模具钢应用范围的有效手段：从表面热处理、化学热处理、电镀、化学镀、气相沉积、三束改性和形变强化几个方面，综述了当前国内外塑料模具表面强化技术的方法、特点和应用，指出了我国塑料模具表面强化技术今后可能的发展，旨在进一步推动其在塑料模具行业的广泛应用。     

基于失效抗力指标的塑料模具材料选择与应用系统

根据塑料模具失效的实际情况,从塑料模具失效机制和塑料模具材料失效抗力指标体系与要求入手,建立基于失效抗力指标的模具材料选择与应用系统,以满足塑料模具设计制造时合理选材.     

NAK80塑料模具钢切削加工性的研究

通过对NAK80塑料模具钢的切削试验,研究了其切削加工性,如切削力、刀具耐用度、加工表面粗糙度和切屑形态。结果表明,在相同切削条件下,NAK80钢的切削力比45钢增大约39%,磨损速率约为45钢的4倍,属较难切削材料,这主要因为钢中存在板条状马氏体及Ni3Al、ε-Cu等硬质点,同时具有高强度和高硬度所致。     

预硬型塑料模具钢切削加工性的研究

通过选取两种典型的预硬型塑料模具钢——P20钢与718钢,从切削力、刀具磨损、表面粗糙度等方面进行切削性能对比实验,来分析这类模具钢的加工特性。结果表明,这类材料属较难加工材料,这主要是由于钢中存在大量硬质点,且材料具有较高强度和硬度所致。     

不同磨损形式下的滑动轴承磨损表面及其磨粒特征

为了对其实现快速和准确的诊断,在试验机上模拟了滑动轴承的各个典型磨损过程,收集各阶段产生的磨粒信息,观察磨损表面形貌,研究了磨粒和磨损表面特征及其对应关系.结果表明通过检测润滑油中的磨粒信息可以间接获得滑动轴承的磨损表面特征,进而进行滑动轴承的状态诊断.     

718塑料模具钢锯切表面不平原因

718塑料模具钢出现锯切表面不平问题.采用化学成分测试、组织形貌观察、微区成分分析以及硬度测试等方法对其表面不平原因进行分析.结果表明:铬、锰和钼元素的偏析是造成锯切表面不平的根本原因;元素偏析使得718塑料模具钢中形成由回火马氏体和回火下贝氏体组成的硬度高于基体组织的硬相组织,导致在锯切过程中产生表面不平问题;建议采...     

热作模具钢的选用及其技术发展探析

分析了热作模具的服役条件、失效因素及对材料的基本要求,介绍了热作模具常用钢材的特性和应用领域,详细介绍了新型模具用钢的性能及应用,可指导正确选材,能有效提高模具使用寿命,并对今后热作模具钢的研发进行了展望。     

气门毛坯终锻模具的失效分析与对策

对气门毛坯终锻模具的失效形式进行了统计分析,发现终锻模具失效主要是圆角R位磨损、R位微细裂纹、整体断裂、R位表面拉伤等几种方式。结合终锻成形过程的计算机模拟和实际模具失效分析,确定了产生失效的主要原因,并提出了相应昀对策。     

铁路钢轨损伤机理研究

钢轨损伤一直是铁路运输中的一个关键问题，损伤类型主要是钢轨压溃、侧磨、波磨和剥离，占钢轨损伤量的80％以上。探讨了这几种钢轨的损伤形式，认为钢轨损伤加剧主要是因为轮轨之间表面摩擦力的增加所致；提高钢轨材质是预防钢轨损伤的最主要方法。     

Estimation of die service life for a die cooling method in a hot forging process

Dies may have to be replaced for a number of reasons, such as changes in dimensions due to wear or plastic deformation, deterioration of the surface finish, breakdown of lubrication, and cracking or breakage. In this paper, die cooling methods are suggested to improve die service life with regards to wear and plastic deformation in a hot forging process. The yield strength of die decreases at higher temperatures and is dependent on hardness. Also, to evaluate die life due to wear, a modified Archard’s wear model has been proposed by considering the thermal softening of die expressed in terms of the main tempering curve. This paper describes the effects of die cooling methods such as cooling hole and direct spray cooling on the life of finisher die during the hot forging of an automobile part. It is shown that the cooling hole method during hot forging is necessary for an effective die service life to be obtained.     

Ti-N系涂层多元多层强化研究进展

TiN系涂层具有高的硬度、耐磨性 ,低的摩擦系数和良好的化学稳定性 ,在工模具上获得广泛的应用。多元多层合金化是强化TiN膜的有效途径之一 ,也是目前研究的热点。本文介绍了几种多元多层TiN薄膜的沉积技术及性能特点 ,并指出了国内TiN涂层的发展趋势。     

Analysis of the tribological behaviour of polymer composite tool materials for sheet metal forming

Today's automotive industry shifts its focus on customised production, facing an increasing demand for medium and small batch production, where cost-effective manufacturability of sheet metal forming dies comes into the foreground. Filled polymers offer possibilities to fulfil such requirements in the ambit of prototype tools manufacturing or in small batch production of sheet metal components. This paper presents investigations dealing with tribological and tool design aspects of using polymeric materials for sheet metal forming purposes. Friction and wear behaviour of two polymer composites on sheet metal counterface materials have been investigated. A new testing method for wear evaluation of polymeric materials for sheet metal forming using a Strip Drawing Test facility is presented and discussed. A method to predict lifetime of polymeric stamping dies using the linear wear–distance relation W_l/s measured with the new testing method is also proposed. Significant improvements in friction and wear performance of polymer composites have been observed using sheet materials with structured surfaces. A theoretical model for abrasive friction and wear of polymer composites on sheet metal counterface material pairs has been developed, based on the results obtained by measurement of friction and wear.     

Effect of Layer Thickness on the Rolling-Sliding Wear Behavior of Low-Temperature Plasma-Carburized Austenitic Stainless Steel

Dry rolling-sliding wear tests have been carried out in the present work to investigate the tribological behavior of the novel surface engineered layers produced on AISI 316 austenitic stainless steel by the low-temperature, plasma-carburizing technique. Three carburized layers with varying thickness, ranging from 15 to 40 m, have been tested using the Amsler configuration. The results show that the carburized layers can prevent surface plastic deformation and improve the wear resistance of the steel during the early stage of the wear process. However, subsurface plastic deformation occurs beneath the layer, leading to the catastrophic failure of the layer and a transition in the wear rate after a limited duration of testing. The thickest layer tested produces the best wear performance under the present rolling-sliding test conditions.     

冷作模具表面硬化层的耐磨性研究

用多弧离子镀及离子氮碳共渗技术对基体钢表面进行了硬化处理。对表面硬化层在不同冲击功下(0J、0.2J、1J)的耐磨性进行了研究,两种表面硬化技术分别应用于不同品种的冷作模具,达到了显著提高模具使用寿命的效果。     

Prediction of contact pressure, slip distance and wear in cold rotary forging using finite element methods

This paper aims to utilize finite element (FE) methods to predict the wear of dies and workpiece in cold rotary forging through systematically investigating the contact pressure and the contact slip distance. For this purpose, a 3D elastic-plastic FE model of cold rotary forging is developed using the FE code ABAQUS. Using this reliable 3D FE model, the evolution and the distribution of contact pressure and contact slip distance are investigated in detail. Consequently, a new insight into the wear that occurs at the surfaces of the dies and the workpiece is gained based on Archard's wear law.