Estimation of Local Mechanical Properties of Steels by Hardness Tests and Its Application to Welded Pipes
Estimation of Local Mechanical Properties of Steels by Hardness Tests and Its Application to Welded Pipes
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通过硬度试验估算钢的局部力学性能及其在焊管中的应用
DOI：
10.11181/hpi.54.16
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发表时间：
2016
期刊：
影响因子：
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通讯作者：
中島弘毅，齋藤裕樹，蓮沼将太，小川武史
中科院分区：
文献类型：
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作者：
中島 康毅;蓮沼 将太;小川 武史;山谷 真和;櫻井 一弥;小川武史，蓮沼将太，渡邉翔太，寒川直輝，金崎俊彦，間野覚文，宮川一夫;中島弘毅，齋藤裕樹，蓮沼将太，小川武史
最近的抗震要求要求在包括塑性变形在内的机械条件下对焊接管道进行评估。虽然焊接金属和热影响区与母材相比具有不同的机械性能，但这些局部特性很难测量。压痕试验是评价局部力学性能包括塑性应力-应变响应的可能方法之一，但其测量存在许多实验困难。本研究的目的是修改的方法简单和方便使用类似于传统的硬度测试的凹痕观察。将改进后的方法应用于管道钢焊接接头，研究了焊缝金属局部力学性能对周围应力分布的影响。管道钢在较低屈服点下表现出显著的屈服延伸率，这在测量局部力学性能的压痕试验中没有考虑。利用数字图像相关技术，可以同时获得局部应变和体应变，在拉伸试验下评价应力-应变响应。在此基础上，讨论了压痕法的局限性。
Recent surge for seismic resistance requires an evaluation for welded pipes under mechanical conditions including plastic deformation. Although the welded metal and the heat affected zone have different mechanical properties compared with those of the base material, these local characteristics are difficult to measure. Indentation test is one of the possible solutions for evaluating local mechanical properties including plastic stress-strain response, however, there are many experimental difficulties for the measurement. The present study aims to modify the method simple and convenient using an observation of dents similar to the conventional hardness testing. The modified method was applied to weld joints of piping steels and utilized to investigate the influence of local mechanical properties of the weld metal on the surrounding stress distribution. The piping steels exhibit remarkable yield elongation under the lower yield point, which is not taken into account in the indentation tests measuring the local mechanical properties. Stress-strain response was evaluated under the tensile test using a digital image correlation technique, by which local and bulk strains could be obtained simultaneously. Based on the result, limitations of the indentation method were discussed.