A method for detecting microscopic cracks in cold work hardening contact fatigue of rolls

Abstract

The invention discloses a roller cold-work hardening contact fatigue microscopic crack detection method, and belongs to the technical field of roller nondestructive testing method; the method is used for detecting cold-work hardening contact fatigue microscopic cracks of a roller in a rolling mill. The method comprises the steps: detecting a measured support roller discharged out of a machine by an ultrasonic flaw detector and a probe, firstly, calibrating the measured support roller, and preparing a DGS curve; then carrying out circumferential and axial scanning on a roller body of the measured support roller; and carrying out fatigue crack qualitation, fatigue crack quantification and fatigue crack positioning on the roller body. The detection method has the remarkable advantages of being safe, reliable, flexible, convenient, and simple to operate, provides a novel and practical detection technology for detection of fatigue cracks of a roller of a hot rolled strip rolling mill, fills up a blank of the cold-work hardening contact fatigue microscopic cracks of the hot-rolled roller, can effectively avoid deepening and development of the fatigue cracks, significantly reduces the production cost, improves the economic benefits, and has great popularization and use values in the industry.

Description

technical field [0001] The invention relates to a detection method for cold work hardening contact fatigue microcracks of rolls in a hot strip rolling mill, and belongs to the technical field of roll non-destructive detection methods. Background technique [0002] With the rapid development of production, the use load of the rolls in the hot rolling mill has increased, and the service life of the backup rolls and roughing work rolls has been greatly extended, resulting in an increase in the normal consumption of the rolls. Due to the long service life and high-intensity production load, "cold hardening contact fatigue microcracks" (hereinafter referred to as fatigue cracks) appear in the roll during use. At present, due to the lack of ultrasonic detection technology for such fatigue cracks, the rolls with cracks cannot be processed in a timely and effective manner, resulting in the unfavorable situation of high roll consumption in hot rolling mills, and even the unfavorable ...

AI Technical Summary

Problems solved by technology

The Hertz formula of contact mechanics shows that the stress peak value in the contact fatigue area is about 10mm below the surface of the roll. The initial crack formation is small and difficult to detect and distinguish, and its development speed is extremely fast. Once the best treatment opportunity is missed, it will lead to production accidents and Huge economic loss

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