国际专利分类表和焊接技术领域的国际专利分类

阐述了有关专利文献,国际专利分类表的一些基本概念。详细介绍了焊接技术领域的国际专利分类的一些基本情况和实践中遇到的一些问题。     

国际互联网上的铸造信息（续完）

本文介绍了一些铸造组织和企业的网址,并做了一些简略说明。     

冷却润滑液是采用集中净化还是分散净化？

本文提出了一些选择冷却润滑液集中净化还是分散净化的准则,指出了在规划集中净化设备时应注意的一些事项,介绍了一些实用的冷却润滑液集中净化设备.图5幅.     

液压传动CAI软件的设计开发

本文介绍了使用计算机快速开发工具对一套多媒体软件进行设计开发的过程,了计算机教学应用与实际教学应用相结合的一些方法和思路,分析了在某些实际情况下一些解决方案的利弊。设想了今后发展的一些可能性。     

消失模在铸造中的应用

消失模作为一种新的铸造方法，由于具有尺寸精度高，铸件轮廓分明的特点，在一些铸造企业得到了广泛的应用。近几年我厂也陆续应用该技术铸造了一些铸件，取得了较好的效果，但同时也出现了一些问题，造成各种各样铸造缺陷，我们经过一段时间的摸索实验，找出了一些解决问题的方法，今在此与各位商榷。     

提高冲裁模具使用寿命的途径与分析

对影响冲裁模使用寿命的各种因素分为模具技术状况与工作环境进行了概括,并就其中一些环节进行了分析,提出了提高模具使用寿命应采取的一些技术措施,特别是模具使用与维护时应注意的一些问题。     

小型精密薄壁塑件注射模设计方法探讨

结合一个例子探讨了小型精密薄壁塑件成型模具设计中的一些关键性问题,并提出了一些可行的方法.     

鞍钢板坯连铸机的生产实践

本文叙述了鞍钢板坯连铸机所采用的一些新技术、新工艺,产品的品种、质量和一些主要工艺技术参数的控制情况,介绍了鞍钢第三炼钢厂多年来在连铸生产方面取得的一些经验和教训。     

热处理时钒碳化物中钒的扩散

在试验中发现含有钒元素的碳化物在热处理中极易分解,为此进行了一些试验,并得出了一些结论。     

凝固模拟的可视化研究

本文介绍了铸件凝固数值模拟结果后处理的一些基本概念以及凝固模拟图形表现方式的一些设计方法 ,在此基础上 ,结合实际应用中用户提出的具体要求 ,提出了在凝固模拟后处理的可视化研究方面的一些具体方法     

A flame-sprayed resistance strain gage for high-temperature applications

The thermal spray technique is often employed for sensor attachments, especially for high-temperature applications, because flame spray techniques usually produce a denser film than ceramic cements. This article introduces a newly developed electrical resistance strain sensor that is installed on the test article by means of a flame spray technique. The gage is made of a specially developed alloy, palladium/13 wt% chromium (Pd13Cr), and is temperature-compensated with a platinum element. A flame-sprayed Pd13Cr-based gage is demonstrated to be a viable sensor candidate for static strain measurement in the temperature range from room temperature to 800 °C (1470 °F). The flame spray technique used for in-stallation of this strain gage is described, and the characteristics of the gage are presented.     

武钢3000mm轧机液压自动厚度控制系统

介绍了武钢 30 0 0mm中板轧机液压自动厚度控制 (HAGC)系统的构成、特点和功能。两年的运行状况 ,证明了 30 0 0mm轧机液压AGC伺服系统的应用是成功的。     

Ti sheet: The effect of gage length and width measurement on plastic strain ratio

The effect of gage length, width measurement locations, and axial strain on plastic strain ratio have been investigated for commercially pure titanium sheet. The specimens were ASTM E 517-92a subsize, type A, and type A alternative. In general, slightly larger length strain values were observed for shorter gage marks. Because of differences in strains of gage lengths and width locations for each specimen type, the magnitude of the calculated R-value depends on the gage length and width measurement locations. Also, for a given gage length and width measurement location, the magnitude of the calculated plastic strain ratio and its variation with axial strain depends on specimen type. The type A specimen resulted in fewer changes in R-value with increased strain than either the subsize or type A alternative specimens. For more information, contact R. Mahmudi, University of Tehran, Department of Metallurgical and Materials Engineering, P.O. Box 11365-4563, Tehran, Iran; +21-611-2254; fax +21-646-1024; e-mail mahmudi@ut.ac.ir.     

The effect of retained austenite stability on high speed deformation behavior of TRIP steels

The safety of passengers is important during an automobile collision. Because a collision event involves high speed deformation, it is necessary to develop property data and understand the applicable deformation mechanisms to aid in the selection of proper materials for crash-related automotive components. Therefore, dynamic mechanical properties of low carbon TRIP steels with varying retained austenite stabilities were evaluated over a wide range of strain rates using a high-velocity hydraulic tensile testing machine. Tensile tests were performed at strain rates ranging from 10² to 6×10² s¹ using standard ASTM E-8 specimens with an elastic strain gage attached to the sample grip end to measure load, and a plastic strain gage mounted onto the gage section to measure strain. Ultimate tensile strengths (UTS), strain rate sensitivities, and strain hardening behaviors are reported. TRIP steel with high stability retained austenite exhibited higher yield stress, lower UTS and lower strain hardening than TRIP steel with low stability retained austenite.     

Strength estimation of self-piercing rivets using lower bound limit load analysis

Abstract

This paper summarises the authors' work on strength and failure mode estimation of self-piercing rivets (SPRs) for automotive applications. First, the static cross tension strength of an SPR joint is estimated using a lower bound limit load based strength estimator. Failure mode associated with the predicted failure strength can also be identified. It is shown that the cross tension strength of an SPR joint depends on the material and gage combinations, rivet design, die design and riveting direction. The analytical rivet strength estimator is then validated by experimental rivet strength measurements and failure mode observations from nine SPR joint populations with various material and gage combinations. Next, the estimator is used to optimise rivet strength. Two illustrative examples are presented in which rivet strength is improved by changing rivet length and riveting direction from the original manufacturing parameters.     

集中差速传动张力减径机各道次壁厚的计算

提出了集中差速传动张力减径机各道次钢管壁厚变化的计算方法,对照分析了理论计算与实际应用的统一性,分析表明,该计算方法实用可靠。     

无缝钢管生产技术的新进展

无缝钢管生产已逐渐从追求产量向提高质量,扩大品种,降低成本方向发展,其间不断涌现新的设备与工艺。简介了国内外生产技术的发展情况;比较了步进式与环形式管坯加热炉的应用特点;概述了锥形辊穿孔机、少机架限动芯棒连轧管机、PQF连轧管机及半浮/在线脱棒技术、紧凑式轧管技术、张力减径机/定径机的三辊可调技术及快速换辊技术、钢管质量自动控制技术(如连轧管机的HGC控制技术、张力减径机增厚端及壁厚自动控制技术)、钢管在线壁厚检测技术等新工艺、新设备的特征。     

Development of Accurate Constitutive Models for Simulation of Superplastic Forming

Superplastic forming (SPF) has been considered a process for improving the formability of aluminum alloys for the production of automotive body panels. In order to accurately simulate the SPF process, elevated temperature, uniaxial tension tests are used to develop the material flow model. Due to the high temperature and large degree of deformation in these tests, strain is typically calculated using crosshead displacement rather than with an extensometer. This approach requires the assumption of a constant material volume in the gage section to calculate the uniform strain. It has been observed that a significant amount of material flows from the grips into the gage section during testing which results in inaccuracies in the material model. This article presents a numerical tool that accounts for material flow from the grips and produces a more accurate constitutive equation. Experimental and numerical validations of the results of the developed tool are presented. This article was presented at Materials Science & Technology 2006, Innovations in Metal Forming symposium held in Cincinnati, OH, October 15-19, 2006.     

Development and evaluation of a novel inclusion seeding methodology for Ti−6Al−4V castings

Hard alpha inclusions in titanium (Ti) investment castings are generally known to have detrimental effects on the mechanical properties of these castings. However, actual inclusions are infrequent and occur in random locations in castings. As a result, it is difficult to obtain tensile or fatigue test specimens of titanium castings with inclusions in the gage section. Quantifying the adverse influence of inclusions on the mechanical properties of castings is, therefore, extremely challenging. To address this problem, a novel artificial inclusion seeding methodology was developed to emulate actual Ti investment casting inclusions. Prefabricated inclusions were seeded into machined holes in cast Ti−6Al−4V plates, the holes were back-filled with plugs of the same Ti alloy and were then electron-beam (EB) welded closed. Hot isostatic pressing (HIP) was utilized to incorporate the inclusions fully into the cast titanium material. Finally, the plates were machined to create mechanical test specimens with inclusions centered in the gage region. Test specimens created by means of this novel artificial seeding methodology were evaluated and found to be equivalent to Ti casting specimens containing actual cast-in inclusions.     

Improving carbon fiber adhesion to polyimide with atmospheric pressure plasma treatment

Plasma treatment is frequently used to modify carbon fiber surfaces to improve adhesion of the fiber to matrices although it may also influence carbon fiber tensile strength. In order to determine the effect of atmospheric pressure plasma treatment on carbon fiber tensile strength and interfacial bonding strength to polyimide, polyacrylonitrile (PAN) based carbon fibers are treated with atmospheric pressure oxygen/helium plasmas for different durations. Tensile strength change of the fiber is studied at different gage lengths before and after the plasma treatment. Interfacial bonding between the carbon fiber and a thermoplastic polyimide matrix is evaluated using a single fiber composite test system. Weibull analysis of the single fiber tensile test data shows no obvious changes in the tensile strength at short gage lengths after plasma treatment while the fiber strength tends to decrease at larger gage lengths. Scanning electron microscopy (SEM) and atomic force microscopy (AFM) show that the plasma treatments roughen the fiber surfaces. X-ray photoelectron spectroscopy (XPS) analysis of fiber surface shows a significant increase of oxygen concentration after plasma treatment and the oxygen containing functional groups reach their maximum levels after 32 s treatment time and further increasing treatment time does not achieve a higher level of oxidation. Plasma treatments decrease dynamic water contact angles and increase the surface energy of the carbon fibers as measured by the modified Wilhelmy method. The interfacial shear strength is improved 21% after the atmospheric pressure plasma treatment for 32 s. It is concluded that the increase of oxygen containing functional groups and changing of the surface topology may contribute collectively to the improvement of fiber/resin interfacial adhesion.