Correlation of the impact elasticity of cast steels with their coercive force

The character of the correlation of the impact elasticity of cast and subsequently normalized and thermostrengthened steels 08XΓΦЛ and 08XΓTЛ with their coercive force is studied. Such a correlation in the form of a curve characterized by a maximum is observed for both low-carbon and low-alloyed hot-rolled steels.     

基于工程应用型人才培养的钢结构设计课程教学改革

对钢结构设计课程教学过程中存在的主要问题进行了分析,从教学内容、教学方法、软件教学、课程设计、毕业设计等方面提出了教学改革建议,并正式开展了系列探索实践,以提高钢结构设计课程教学质量和学生的工程应用能力,培养高素质的应用型专业人才。     

基于相干激光雷达的激光微多普勒探测

利用相干激光雷达探测目标微动特性技术是一种以单频激光为光源,用外差探测的方式实现对低速、低频多个运动物体进行微多普勒信息提取和识别的技术.以波长为1.064 μm的窄线宽单块激光器为光源,发射激光经过模拟长距离传输的4 km的光纤延迟,照射到以扬声器的发声单元和电动平移台为目标的微动物体上,目标反射的激光会聚进入单模光纤,参考光与信号光通过3 dB光纤合束器线性耦合进入同一根光纤,并在探测器表面进行相干.用于接收相干信号的探测器的接入方式为光纤输入,带宽为3.5 GHz.利用时间-频率域联合描述的方法对数/模(A/D)采样后的数据进行分析.在4 km光纤延迟时,本系统最低探测速度为0.5 mm/s,速度分辨率达到毫米每秒量级,频率分辨率达到千赫兹量级.利用微多普勒信息探测技术,实现了探测物体表面的微动状态信息和识别运动状态的目的.     

Critical Fields for Displacing Domain Walls in Low-Alloyed Tempered and Martensite-Aging Steels

By analyzing experimental curves of differential magnetic susceptibility of thermally processed samples of 38KhS, 75G, and N18K9M5T steels versus magnetizing field, we have derived characteristic curves ₁₈₀(H) and ₉₀(H) due to displacement of 180° and 90° domain walls and determined critical fields H ₁₈₀ and H ₉₀ for these types of domain walls. Fields due to induced magnetic anisotropy have been calculated, alongside their components caused by internal stress and nonferromagnetic inclusions.     

Experience of Using the Nondestructive Quality Testing for Articles from 40Kh Steel

Nondestructive methods for testing the hardness of articles made of 40Kh steel and subjected to quenching, including stepwise (warm) hardening with post-quenching, and subsequent tempering on various temperature intervals are considered.     

Construction of plastoelastic loading diagrams of structural steels based on magnetic properties

A model of plastoelastic strains of steels was constructed based on the values of the coercive force. The model was successfully applied to specimens constructed from Ст.Зсп steel after different regimes of hot rolling.     

Increasing the reliability of the multiparametric method for nondestructive testing of mechanical properties of articles

It is suggested that the corrected least squares procedure be applied in order to improve the results obtained during nondestructive testing of the service properties of articles by the multiparametric method. The result of the statistical manipulation, which is given in the form of a correlation between the calculated and experimental magnitudes of a tested property, improves the pair correlation in use of a procedure developed earlier [1]. The conditions of the expediency of applying such improvement are studied.     

Differential Magnetic Method of Nondestructive Testing and Phase Analysis

In tests of roller-bearing, tool, and other sorts of alloyed steels, two magnetic char-acteristics must be measured in nondestructive tests of quenched structures, namely, the saturation magnetization and coercive force. In industrial conditions, a differential method is used in measuring these parameters with the help of an instrument built around an H-shaped applied electromagnet. The paper considers utilization of this magnet in nondestructive measurements of hardness of bearing components manufactured from the ShKh15, ShKh15SG, and 95Kh18 steels, pump elements from the ShKh15 steel, and components manufactured by sintering. A technique for estimating the content of residual austenite in the mentioned sorts of steel and martensite in steels of transitional sorts, in particular, Kh16N6, is described.     

钢框架梁柱焊接连接的半刚性及其对结构自振频率影响的研究

先从梁柱节点受弯变形的机理入手,推导出钢框架梁柱焊接连接节点的初始刚度计算公式.通过对5组共25个梁柱焊接节点的初始刚度公式计算结果与有限元计算结果的比较,发现该计算公式与有限元结果吻合较好.然后通过通用有限元软件ABAQUS分析随结构层数、跨数变化时节点半刚性对框架结构自振频率的影响规律,由此建立焊接连接简化为刚性连接的条件.