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A weld shape design method to make the fatigue performance of the welded joint the same as that of the base metal

A welding joint, fatigue performance technology, applied in welding equipment, metal processing equipment, manufacturing tools, etc., can solve problems such as uncertain load spectrum, variable amplitude fatigue, and inconvenient joint design

Active Publication Date: 2021-12-24
HARBIN INST OF TECH
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

For constant amplitude fatigue, the bearing capacity of the base metal can be characterized by the conditional fatigue strength, but the actual working condition of the welded structure is often variable amplitude fatigue, and even the load spectrum is uncertain, which brings great inconvenience to the joint design

Method used

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  • A weld shape design method to make the fatigue performance of the welded joint the same as that of the base metal
  • A weld shape design method to make the fatigue performance of the welded joint the same as that of the base metal
  • A weld shape design method to make the fatigue performance of the welded joint the same as that of the base metal

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specific Embodiment 1

[0075] according to figure 1 As shown, the present invention provides a welding seam shape design method that makes the fatigue performance of the welded joint the same as that of the base metal, including the following steps:

[0076] A welding seam shape design method that makes the fatigue performance of the welded joint the same as that of the base metal. When the base metal and the weld have no cracks, the following steps are included:

[0077] Step 1: Determine the ratio of the fatigue limit of the weld deposited metal to the base metal and the ratio of the tensile strength of the weld deposited metal to the base metal;

[0078] Step 2: According to the ratio of the weld deposited metal to the fatigue limit of the base metal and the ratio of the weld deposited metal to the tensile strength of the base metal, select the generalized matching ratio with the smallest value to determine the load used in the design;

[0079] Step 3: When the base metal and the weld have no cr...

specific Embodiment 2

[0139] The general form of load-bearing realization conditions such as welded joints is: the generalized mechanical concentration coefficient is not greater than the generalized matching ratio. Under the action of fatigue load, the bearing capacity of the component is characterized by the load P and the life N. The general form of this load-bearing realization condition is that the fatigue life of the welded joint and the smooth base metal are the same, and the equivalent matching ratio is the condition Fatigue strength matching ratio, when the load size changes, the equivalent matching ratio changes accordingly. That is to say, even if the load form is determined, under the action of fatigue load, the critical curve of the weld changes with the load, which is different from the case of static load.

[0140] In order to study the influence of the load size, the equal bearing idea can be equivalently expressed as, under the same load, the fatigue life of the weld metal is not l...

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Abstract

The invention is a welding seam shape design method for making the amplitude-changing fatigue performance of the welded joint the same as that of the base metal. For both the base metal and the weld without cracks, the ratio of the stress of the weld to the base metal is equal to the ratio of the weld deposited metal to the fatigue limit of the base metal, the tensile strength of the weld deposited metal to the base metal by adjusting the weld geometric parameters The smaller value in the ratio of the welding seam and the base metal can achieve load bearing such as fatigue fatigue; for both the base metal and the weld have cracks, the ratio of the stress intensity factor of the weld to the base metal is equal to that of the weld by adjusting the geometric parameters of the weld The smaller value of the ratio of the threshold value of the stress intensity factor of the deposited metal to the base metal and the ratio of the critical stress intensity factor of the weld deposit to the base metal is used to achieve load bearing such as fatigue of the weld and the base metal. Keeping the safety margin unchanged, the thickness of the base metal can be reduced by adopting load-bearing designs such as variable-amplitude fatigue to achieve lightweight; keeping the thickness of the base metal unchanged, adopting load-bearing designs such as variable-amplitude fatigue can increase the safety margin and improve the load-carrying capacity.

Description

technical field [0001] The invention relates to the field of welding technology, and relates to a welding seam shape design method for making the amplitude-changing fatigue performance of a welded joint the same as that of a parent material. Background technique [0002] The development of high-strength steel is currently the main practice to reduce the weight of steel structures and ensure reliability, and to meet resource and environmental challenges. However, the bearing capacity of welded joints of high-strength steel (especially high-cycle fatigue bearing capacity) is lower than that of the base metal, and the tendency of brittle fracture is large, which greatly limits the application of high-strength steel in welded structures. In the case of static load, through complex preheating and postheating processes, developing special welding materials, or adopting low-matching welded joint static load and other bearing designs, the bearing capacity of welded joints can be the...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): B23K31/12B23K33/00
CPCB23K31/12B23K33/00
Inventor 董志波郭军礼周守振卢伟泽方洪渊
Owner HARBIN INST OF TECH