Method for measuring sheet welding residual stress

A technology of residual stress and measurement method, applied in the direction of measurement force, measurement device, instrument, etc., to achieve the effect of high reliability, low equipment cost, and high measurement accuracy

Active Publication Date: 2014-05-21
ZHEJIANG UNIV OF TECH
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0006] Aiming at the shortcomings of existing residual stress measurement methods, the present invention provides a new method for measuring thin plate welding residual stress

Method used

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  • Method for measuring sheet welding residual stress
  • Method for measuring sheet welding residual stress
  • Method for measuring sheet welding residual stress

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0023] A Q235 steel plate with a size of 200mm×75mm×2.5mm was welded by tungsten inert gas shielded arc welding method without adding wire.

[0024] a. Paste two rows of symmetrically distributed BF350 high-precision resistive strain gauges 2 on the weldment 1, so that they are distributed on two straight lines 25mm away from the two long sides. The distance between the two rows of strain gauges is 25mm, and the same row The adjacent BF350 high-precision resistance strain gauges 2 are separated by 20mm, and the direction of the strain grid is consistent with the direction of the weld 3. Record the initial readings of the strain gauges, and adjust the initial readings of the two sets of strain gauges to zero with a pre-adjusted balance box. Number the two columns of strain gauges 2 from left to right;

[0025] b. Use the high-precision AW310T slow-moving wire cutting machine (wire diameter: Ф0.3mm) to cut the weldment 1 into two parts of the same size along the direction perpen...

Embodiment 2

[0038] The blind hole method is used to test the residual stress measurement of thin plate welding. The material is also Q235 steel plate welded by tungsten inert gas shielded arc welding method without wire surfacing, and the size remains unchanged.

[0039] A, each strain gauge sticking point among the embodiment 1 is used as the test site, and the position of each measuring point is marked with a marking pen;

[0040] b. Paste BE120-2CA-K type 3-way strain rosettes on each measuring point;

[0041] c. Connect all 3-way strain rosettes to the YC-III strain measuring instrument, input the calibrated release coefficient into the instrument, and perform zero adjustment on the instrument;

[0042] d. Use the ZDL-1 drilling instrument to drill holes at the measuring points in sequence, and drill holes to a depth of 2mm at a slow speed;

[0043] e. After the drilling is completed, the instrument will automatically calculate the stress value from the measured strain value and reco...

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Abstract

The invention relates to a method for measuring sheet welding residual stress. The method comprises the steps of sticking two rows of symmetrically distributed resistance strain gages on a weldment at first and enabling the direction of a strain grid to be consistent with the direction of a weld joint, next, cutting the weldment into two parts with the same size in a direction perpendicular to the weld joint so that the residual stress is released, observing and recording the changes of readings of the two groups of strain gages to obtain two groups of strain values released in the direction of the weld joint, and performing numerical value averaging on the obtained two groups of strain values of the two cut surfaces of the weldment, carrying out polynomial fitting through EXCEL, and finally, obtaining an original residual stress distribution curve in the direction of the weld joint through conversion according to Hooke's law. The method has the beneficial effects of high measurement accuracy, multi-point measurement, high reliability, convenient operation and low equipment cost.

Description

(1) Technical field [0001] The invention relates to the measurement technology of structural residual stress in the engineering field, in particular to a measurement method of thin plate welding residual stress. (2) Background technology [0002] Residual stress refers to the stress that exists in the structure in the absence of external load. The generation of residual stress comes from the non-uniform permanent deformation of the object, such as heat treatment, surface treatment, rolling, welding, casting, etc., and because in the process of manufacturing or assembly, the material will be subject to local plastic deformation, so almost all structures, There are residual stresses. [0003] The residual stress of welded components is more harmful. On the one hand, the strength of the workpiece will be reduced, causing process defects such as deformation and cracking of the workpiece during manufacturing; on the other hand, the size of the workpiece will change or the Its m...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): G01L1/22
Inventor 周号杨建国雷靖谢志刚高增梁董浩龙徐文东金伟娅
Owner ZHEJIANG UNIV OF TECH
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