Correcting method for influences of grain size on ultrasonic evaluation for welding residual stress
A technology of grain size and residual stress, used in force/torque/work measuring instruments, measuring devices, instruments, etc., can solve problems such as hidden safety hazards of welded structures, and achieve the effect of online evaluation
Inactive Publication Date: 2017-04-26
JIANGSU UNIV OF SCI & TECH
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Problems solved by technology
Although the above studies can improve the service safety and reliability of welded structures to a certain extent, they still focus on the control of welding residual stress, and have not really realized the evaluation of welding residual stress, which inevitably brings safety to the service of welded structures. Hidden danger
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Embodiment 1
[0030] Taking carbon steel as an example to describe the correction steps of grain size affecting ultrasonic evaluation of welding residual stress, the specific process is as follows:
[0031] Step 1: Select 45 steel with a thickness of 12mm as the welding base material, measure its carbon content to be about 0.45%, formulate the heat treatment process curve in combination with the Fe-C binary alloy phase diagram, and obtain six groups of samples with different grain sizes, Marked as S1-S6 respectively, the metallographic structure is as figure 1 shown. The heat treatment process and grain size are shown in Table 1.
[0032] Table 1 Heat treatment process parameters and grain size of 45 steel
[0033]
[0034]
[0035] Step 2, according to GB / T2002-228 room temperature tensile test method for metal materials, prepare static load tensile samples with a thickness of 3mm, and measure the yield strength of S1-S6 samples.
[0036] Step 3: Fix the excitation parameters of t...
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The invention discloses a correcting method for influences of grain size on ultrasonic evaluation for welding residual stress and belongs to the technical field of ultrasonic nondestructive evaluation. The method comprises the following steps: utilizing ultrasonic energy attenuation analysis to optimize and prepare a double ultrasonic probe at a constant interval; utilizing a pressure-adjustable device to clamp the ultrasonic probe, thereby acquiring an ultrasonic signal with stable amplitude; adopting a metal thermal treatment method for acquiring the samples in different grain sizes; establishing a relationship between ultrasonic sound elastic constant and grain size on the basis of an ultrasonic sound elastic constant calibration test, thereby realizing the correction for a sound elastic constant in a heat affected zone of a welding joint; and acquiring the ultrasonic sound elastic constant of the seam of the welding joint through the ultrasonic sound elastic constant calibration test and lastly realizing the correction for the ultrasonic evaluation for the residual stress of the welding joint. The invention provides a technical support for the correction for the influences of the grain size on the ultrasonic evaluation for the welding residual stress and the correcting method has the advantages of no damage, high speed, convenience, safety, and the like.
Description
technical field [0001] The invention belongs to the technical field of ultrasonic non-destructive evaluation, and specifically relates to a correction method for the influence of grain size on ultrasonic evaluation of welding residual stress. Background technique [0002] The service safety and reliability evaluation of welded structures is the key to promote the efficient and safe integration of welded products into the market cycle. Therefore, it is urgent to discuss the technical methods that can realize the service safety and reliability evaluation of welded structures. Relevant studies have shown that welding residual stress is one of the important factors affecting the service safety and reliability of welded structures. For this reason, scholars at home and abroad have conducted a lot of research on welding residual stress, mainly including the following three aspects: ① Optimization of welding process; ② Research and development of new welding equipment and new metho...
Claims
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Login to View More IPC IPC(8): G01L5/00
CPCG01L5/0047
Inventor 刘彬吴绪磊李继明缪文炳李瑞峰
Owner JIANGSU UNIV OF SCI & TECH