施工中电焊机的安全使用简述

从电焊机自身电气特点及建筑工地工作环境入手,探讨电焊机安全技术的实施方法。分析电焊机安全隐患及事故的分类以及电焊机在使用过程中产生危险的原因。介绍电焊机在安装以及作业过程中的安全措施。     

Model repair — aligning process models to reality

Process mining techniques relate observed behavior (i.e., event logs) to modeled behavior (e.g., a BPMN model or a Petri net). Process models can be discovered from event logs and conformance checking techniques can be used to detect and diagnose differences between observed and modeled behavior. Existing process mining techniques can only uncover these differences, but the actual repair of the model is left to the user and is not supported. In this paper we investigate the problem of repairing a process model w.r.t. a log such that the resulting model can replay the log (i.e., conforms to it) and is as similar as possible to the original model. To solve the problem, we use an existing conformance checker that aligns the runs of the given process model to the traces in the log. Based on this information, we decompose the log into several sublogs of non-fitting subtraces. For each sublog, either a loop is discovered that can replay the sublog or a subprocess is derived that is then added to the original model at the appropriate location. The approach is implemented in the process mining toolkit ProM and has been validated on logs and models from several Dutch municipalities.     

Linear friction welding of Ti6Al4V: experiments and modelling

Linear friction welding of the Ti6Al4V alloy is studied. A new definition of the energy input rate is proposed, based on an integration over time of the in-plane force and velocity; a strong correlation with the upset rate is then found. The effective friction coefficient is estimated to be 0·5±0·1 for varying frequencies and amplitudes, with only a weak dependence on the processing conditions displayed. A model is proposed that accounts for both the conditioning and equilibrium stages of the process, which is shown to be in good agreement with the experimental data. The model is used to study the mechanism by which the flash is formed. A criterion is proposed by which the rippled nature of its morphology can be predicted.     

二氧化碳气体保护焊在厚板上的应用

板厚为 5 5mm的 16Mn钢采用CO2 半自动气保焊建造大型转炉炉体的可能性和可靠性如何 ?目前尚缺少足够的试验数据。为了给转炉工程的施工焊接提供可靠数据 ,确保焊接质量 ,对板厚 5 5mm16Mn钢CO2 半自动的焊接性能进行了一系列的试验研究     

热作模具钢表面激光堆焊耐磨合金层的研究

本文主要通过在H13钢上用大功率CO_2激光束进行堆焊,阐述了激光堆焊工艺变化对堆焊组织和性能的影响,在本试验条件下,得到了高密度弥散金属化合物组织的激光堆焊层,平均硬度为HV800,与基体呈冶金结合,耐磨性比H13模具钢提高149%。     

Quantitative feedback theory with applications in welding

Two different control systems were developed using quantitative feedback theory for weld quality improvement. The first application to be discussed was designed for the resistance pinch welding process and uses electrode displacement and force as feedback parameters. A correlation between weld quality and electrode displacement is established for constant electrode force. The system is capable of producing repeatable welds of consistent quality, with wide variations in weld parameters. This is the first time feedback control has been successfully applied to pinch welding. The second example presented in this paper was developed for penetration control of the gas-tungsten-arc welding process. The feedback signal is obtained by measuring the amount of light emitted from the back side of the weld. Welds of constant penetration have been demonstrated in tests with travel speeds varying from 1.5 to 6 inches per minute and with 200 per cent changes in part thickness.     

新型交流脉冲MIG焊接法的研究

采用自行研制的具有方框形外特性的交流脉冲MIG焊接电源 ,又设计了双凹形焊接电流波形 ,即过零前后的电流波形均为脉冲大电流 ,有利于交流脉冲MIG焊接电弧的连续稳定。按照这个新型交流脉冲MIG焊接方法 ,不必加任何稳弧措施 ,可实现电弧的稳定燃烧 ,解决了电弧磁偏吹的问题 ,具有较好的焊接工艺性能 ,用于压力容器的全位置焊接和铝焊接均有很好的焊缝成型     

水力喷射径向水平井生产管的工艺评定与检验

在URRS系统施工过程中 ,生产管处于多种变化复杂的应力和变形状态下 ,若出现失稳、渗漏、刺穿和断裂等事故 ,将造成巨大经济损失。为此 ,开展了水力喷射径向水平井用生产管的焊接方法、焊接设备、焊接工艺过程和焊接接头力学性能评定方法的试验研究。通过研究和试验 ,管材基本上实现了国产化 ,与之相匹配的焊接材料、焊接工艺以及质量检测技术已基本配套和规范化 ,形成了一套稳定的、可靠性较高且能完全满足现场工况的施工体系和质量保证体系     

不锈钢及镍基堆焊层厚度测量

叙述了运用磁性法或超声法对核电和化工容器中不锈钢及镍基堆焊层厚度进行测量的原理、方法及主要影响因素 ,比较了这两种方法的测量结果     

合成氨中置锅炉的修复

本文在分析中置锅炉失效原因的基础上，提出了详细的修复措施，为类似情况的设备修复提供了借鉴。