Method for measuring yield strength of Q345 low alloy steel by using nonlinear ultrasonic technique

A non-linear ultrasonic and low-alloy steel technology, which is applied to the analysis of solids using sound waves/ultrasonic waves/infrasonic waves, and can solve problems such as slow measurement speed

Inactive Publication Date: 2014-04-09
STATE GRID CORP OF CHINA +1
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  • Abstract
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  • Claims
  • Application Information

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Problems solved by technology

[0006] The purpose of the present invention is to solve the problem that when the existing tensile (compression) test method tests the yield strength of the material, it is destructive to the material, and it is impossible to detect all the materials in the production process of the material and the small sample method, cycle In view of the problem of slow determination of hardness testing methods and other methods, a method for measuring the yield strength of Q345 low-alloy steel using nonlinear ultrasonic technology is provided.

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  • Method for measuring yield strength of Q345 low alloy steel by using nonlinear ultrasonic technique
  • Method for measuring yield strength of Q345 low alloy steel by using nonlinear ultrasonic technique
  • Method for measuring yield strength of Q345 low alloy steel by using nonlinear ultrasonic technique

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specific Embodiment approach 1

[0018] Specific embodiment one: a kind of method of this embodiment adopts nonlinear ultrasonic technology to measure the yield strength of Q345 low-alloy steel according to the following steps:

[0019] Step 1. Prepare n groups of standard Q345 low-alloy steel tensile specimens with thickness × width × length of 10 mm × 40 mm × 300 mm with different degrees of cold work hardening;

[0020] Step 2: Perform nonlinear ultrasonic measurements on the n groups of standard Q345 low-alloy steel tensile specimens prepared in step 1 with different cold work hardening degrees and the dimensions are 10mm×40mm×300mm, and calculate n groups of nonlinear ultrasonic quadratic factors beta;

[0021] Step 3, measuring the yield strength values ​​of Q345 low-alloy steel with different degrees of cold work hardening degree for n groups prepared in step 1;

[0022] Step 4, the yield strength values ​​of n groups of standard Q345 low-alloy steel samples measured by step 2 and n groups of non-line...

specific Embodiment approach 2

[0026] Specific embodiment 2: The difference between this embodiment and specific embodiment 1 is: in the step 1, the standard Q345 low-alloy steel tensile test method with thickness × width × length of 10 mm × 40 mm × 300 mm in different cold hardening degrees is prepared for:

[0027] Select n groups of strip-shaped Q345 low-alloy steel samples with thickness×width×length of 20mm×80mm×300mm, and stretch these n groups of Q345 low-alloy steel samples with a tensile testing machine to obtain the thickness by 20mm ~ 12mm n groups of Q345 low alloy steel samples, wherein the thickness of the sample after deformation is 100% ~ 60% of the original thickness; then n groups of Q345 low alloy steel samples are made into n groups of different cold Standard Q345 low-alloy steel tensile test specimen with thickness × width × length dimensions of 10mm × 40mm × 300mm for hardening degree; where n≥6. Other steps and parameters are the same as those in Embodiment 1.

specific Embodiment approach 3

[0028] Specific implementation mode three: the difference between this implementation mode and specific implementation mode one or two is: the method of calculating nonlinear ultrasonic quadratic factor β in step two is as follows figure 2 :

[0029] (1) The computer sends an instruction to notify the nonlinear ultrasonic generator; after receiving the instruction, the ultrasonic generator sends a sine or cosine electrical signal with a frequency of 2MHz to 5MHz for more than 5 consecutive cycles;

[0030] (2) The electrical signal from the ultrasonic generator is filtered by a low-pass filter to filter out frequency waves above 20MHz;

[0031] (3) The filtered electrical signal reaches the single-frequency straight probe at the transmitting end. The single-frequency straight probe uses the piezoelectric effect to convert the electrical signal into a mechanical ultrasonic wave. The mechanical ultrasonic wave passes through the contact interface between the single-frequency st...

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Abstract

The invention discloses a method for measuring yield strength of Q345 low alloy steel by using a nonlinear ultrasonic technique, which relates to methods for measuring yield strength of Q345 low alloy steel. The method for measuring yield strength of Q345 low alloy steel by using nonlinear ultrasonic technique provided by the invention is used for solving the problems that a traditional steel yield strength measurement method is destructive and the measurement speed is low. The method comprises the following steps: 1. preparing n groups of standard Q345 low alloy steel tensile samples with different cold hardening degrees and with thickness*width*length sizes of 10mm *40mm*300mm; 2. calculating n groups of nonlinear ultrasonic secondary factors beta; 3. measuring the yield strength values of n groups of Q345 low alloy steel; 4. fitting a curve graph; 5. measuring the yield strength value of any Q345 low alloy steel; and the method disclosed by the invention is applied to the field of measurement of yield strength of Q345 low alloy steel.

Description

technical field [0001] The invention relates to a method for measuring the yield strength of Q345 low alloy steel. Background technique [0002] Yield strength is the maximum load that a material can withstand without permanent deformation. It is one of the most important indicators for evaluating structural strength and is affected by the chemical composition, microstructure and mechanical deformation state of the material. Tensile (compressive) mechanical performance test is the fundamental method to determine the yield strength of materials, which has a complete theoretical basis and strict scientific definition. [0003] The test method of tensile (compression) mechanical properties needs to prepare a standard sample, which will cause damage to the material, and its measured value only strictly represents the yield strength of the tested sample. In the application of engineering quality control, this method is based on the assumption that materials produced under the sa...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): G01N29/12
Inventor 王晓林池永斌张曰涛
Owner STATE GRID CORP OF CHINA
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