Ultrasonic surface wave nonlinear detection method for roll fatigue hardening layer

Abstract

The invention relates to the roll quality detection field, in particular to a nondestructive detection method for a roll fatigue hardening layer. The ultrasonic surface wave nonlinear detection method for the roll fatigue hardening layer includes: firstly preparing series of standard test blocks with different fatigue hardening layer thicknesses, conducting surface acoustic wave second harmonic detection on the known series of standard test blocks with different fatigue hardening layer thicknesses to obtain a monotonous corresponding relation between the second harmonic strength and the hardening layer thickness, employing acoustic surface wave to detect a test roll, and comparing the result with the corresponding relation to obtain a corresponding thickness value of the fatigue hardening layer. By adopting nonlinear second harmonic generation effects in an ultrasonic surface wave propagation process, the method provided by the invention realizes detection of the roll fatigue hardening layer, and provides an effective nondestructive detection means for quantitative evaluation of the roll fatigue hardening layer. With accurate and reliable detection results, the method can well cooperate with the grinding optimization work of a roll at a steel production spot, saves the production cost and ensures production safety.

Description

technical field [0001] The invention relates to the field of roll quality detection, in particular to a non-destructive detection method for a roll fatigue hardened layer. Background technique [0002] The rolling mill is the key process equipment of modern metallurgical enterprises, and the roll is the key core component of the rolling mill. Its performance directly determines the stability of the rolling mill, the smooth running of the production line, production consumption and product quality. The most economical and safe use of rolls is of great significance to production. The large contact fatigue stress of the rolls will cause the fatigue layer on the surface of the rolls. The contact fatigue damage caused by this is a common phenomenon in many domestic iron and steel enterprises. In order to prevent roll cracking and spalling accidents, it is necessary to develop a non-destructive testing technology for roll fatigue damage that can ensure the safe and stable operatio...

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Problems solved by technology

Hardness testing is a kind of dynamic force testing. The commonly used Shore hardness tester is a portable portable instrument, which is convenient for on-site testing. It has a simple structure, is easy to operate, and has high testing efficiency. Compared with the traditional method, the accuracy is slightly worse, and the data is more dispersed due to factors such as the verticality of the test and the surface finish of the sample. The comparison of the test results is limited to materials with the same elastic modulus. There are certain requirements for weight, which is not suitable for thinner fatigue hardened layers, and there are differences in the hardness of the roll body, so it is difficult to accurately quantitatively analyze and evaluate the microscopic fatigue layer in hardness testing

[0006] 3) X-ray detection: As early as the 1980s, the foreign iron and steel industry conducted in-depth research on the fatigue hardened layer of the roll using the X-ray method, and X-ray was carried out on the change of the material lattice structure data and the fatigue limit during the fatigue strain period. -ray detection and analysis, but there are few ways to quantitatively determine fatigue damage based on the above detection methods

Compared with other detection methods, the X-ray diffraction method is an effective detection method before fatigue develops into visible cracks, but the biggest problem with this method is that its detection depth is limited, and it can only detect about 20 microns below the surface. The detection is carried out in the depth range, compared with the fatigue hardened layer of hundreds of microns on the roll, the workload to achieve a thorough inspection is very large

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