摘要本文介绍了一种新型焊接接头冷热疲劳试验机的研制。新型试验机保留了参考试 验机的优点，并在参考试验机的基础上作了大量的改进。在主机部分，电炉中采用了 新型保温材料，显著提高了加热效率；在冷却部分的设计上采用了液面自动稳定结构， 并增加了水压稳定装置和水温测温装置。控制部分全部采用数字仪表，温度控制器和 动态测温仪均才用了高精度只能可编程控制器，大幅度地提高了控制和测量精度。试 验机还增加了循环次数预置和自动停机以及极限保护等功能，有效地提高了设备的自 动化程度。80930

本项目研制的焊接接头热疲劳试验机技术性能、自动化程度适用于不同形状、不 同规格金属热疲劳试验，尤其适用于焊接接头热疲劳试验。更重要的是解决了以下存 在的两个问题。一是可预置循环次数，即当实际循环次数达到预置次数时，可自动停 止试验的进行；二是试样夹具可以一定速率自行旋转，很好地解决了在热疲劳实验过 程中试样受热不均匀导致实验结果不准确的问题，优化了热疲劳试样效果，同时也解 决了试样在水槽中冷却不均匀的问题。

毕业论文关键词：热疲劳试验机；主机；自动化；控制系统；循环次数；自行旋转

Abstract This paper introduces the development of a new type of cold and hot fatigue testing machine for welding joints 。The new machine preserves old machine’s advantage and makes many improvement based on the old machine 。A new heat preservation material is used in the oven that located in host machine ,so heating efficiency is significantly improved 。 Meanwhile, stability structure of automatic liquid level is applied in design part,in addition device of liquid pressure stability and devices of temperature measurement。 The digital instruments are applied in the control unit, and high precession intelligence programmable controller is used in temperature controller and dynamic temperature measurement instrument。 Therefore, control and measure precession is improved。 The functions of cycle time presetting and automatic stop and limitation protection are also added in the machine to effectively improve the automation。

The thermal fatigue testing machine of welding joints developed by this project can be used in different shapes and sizes of metal thermal fatigue test, especially for the thermal fatigue test of welded joints。 More important is to solve the following two problems。 Preset cycles, when the actual cycle number reaches a preset number, can automatically stop the test; specimen fixture can rate rotate on their own, well solves the during the thermal fatigue test of sample heating due to the uneven inaccurate results problem, optimize the thermal fatigue effect, but also solve the specimen in the tank cooling uneven problem。

Key words: thermal fatigue test machine; host machine; automation; control system;

cycle times; Self rotation

目录

第 1 章  绪   论 1

1。1 课题背景 1

1。2 冷热疲劳 1

1。2。1 冷热疲劳概述 1

1。2。2 热疲劳的现状及发展趋势 3

1。2。3 热疲劳性能 6

1。3 试验机的研制 9

1。3。1 国内外研究现状 9

1。3。2 研制前景预测 11

1。4 研究内容与意义 12

1。4。1 研究目的 12

1。4。2 研究意义