A method for measuring the fracture toughness jic of the heat-affected zone of welded joints

A heat-affected zone and fracture toughness technology, which is applied in the preparation of test samples, and the use of stable bending force to test the strength of materials, etc., to achieve the effects of ensuring effectiveness, improving data accuracy, and convenient operation

Active Publication Date: 2018-05-04
SHANGHAI JIAOTONG UNIV
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  • Abstract
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Problems solved by technology

[0005] In order to solve the above-mentioned two problems existing in the measurement of the fracture toughness of the heat-affected zone of the welded joint in the prior art, the present invention proposes a method for measuring the fracture toughness of the heat-affected zone of the welded joint, by controlling the lowering of the beam during the three-point bending test The compression velocity and the method of opening a V-shaped groove on the three-point bending specimen can effectively measure the J integral value of the heat-affected zone, thereby calculating its fracture toughness J IC

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  • A method for measuring the fracture toughness jic of the heat-affected zone of welded joints
  • A method for measuring the fracture toughness jic of the heat-affected zone of welded joints
  • A method for measuring the fracture toughness jic of the heat-affected zone of welded joints

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Embodiment 1

[0027] The measurement of the fracture toughness J of the heat-affected zone of the welded joint in this embodiment IC The method mainly includes the following steps:

[0028] (1) Taking a sample with a thickness of 15mm as an example, process 8 to 10 three-point bending samples. The three-dimensional schematic diagram of the sample is shown in figure 1 , see the specific size figure 2 , where the depth of the V-groove is 1.5mm, the angle is 60°, and the bottom fillet radius is 0.2mm;

[0029] (2) Perform fatigue crack prefabrication on the three-point bending specimen on the fatigue testing machine, where the maximum load is 10kN, the minimum load is 1kN, the stress ratio R is 0.1, and the fatigue crack length is about 2.0mm;

[0030] (3) Perform a three-point bending test on a universal testing machine, load the first sample to the maximum load, distribute the remaining samples evenly between the maximum load point and the end point of the elastic stage, and perform a thr...

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Abstract

The invention discloses a method for measuring the fracture toughness JIC of each micro-region in the heat-affected zone of a welded joint, which is suitable for measuring the fracture toughness of various welded joints. The invention can effectively control the direction of crack propagation by welding the coarse-grained or fine-grained area of ​​the heat-affected zone on the three-point bending sample to open a V-shaped groove, so as to ensure that the crack expands in the coarse-grained or fine-grained area of ​​the heat-affected zone, thereby measuring The fracture toughness of each micro-zone in the heat-affected zone of the welded joint. The method of the invention is simple, low in cost, and the measurement result is true and reliable, and has great significance for evaluating the mechanical properties of each micro-region of the welded joint, determining the weak link of the welded joint and studying the fracture toughness of the heat-affected zone of the welded joint.

Description

technical field [0001] The invention relates to the field of testing the fracture mechanical properties of welded joints, in particular to a method for measuring the fracture toughness J of each micro-zone in the heat-affected zone of the welded joint. IC The method is applicable to the determination of fracture toughness of various welded joints. Background technique [0002] In recent years, people have paid more and more attention to the study of fracture toughness of welded engineering structures. Some major engineering structures, such as nuclear reactors, large ships, offshore platforms, oil and gas pipelines, etc., will face heavy losses and disasters once cracks appear that may lead to the disintegration of the structure. and engineering applications are of great significance. The parameters for evaluating the fracture toughness of materials are fracture toughness K IC 、J IC And, CTOD (crack tip opening displacement), etc., for most metal materials, can be measur...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): G01N3/20G01N1/28
Inventor 芦凤桂郭谦崔海超唐新华王朋丁玉明刘霞
Owner SHANGHAI JIAOTONG UNIV
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