Laser rapid repairing method for high chromium cast steel roller surface layer fatigue micro cracks

Abstract

The invention relates to a laser rapid repairing method for high chromium cast steel roller surface layer fatigue micro cracks. The laser rapid repairing method is used for rapidly conducting laser repairing on high chromium cast steel roller surface layer fatigue micro cracks in order to obtain a corrosion-resistant and high-temperature-corrosion-resistant surface reinforced layer. The laser rapid repairing method is characterized by comprising the steps that (1) surface preprocessing is carried out a high chromium cast steel sample with surface fatigue micro cracks, the high chromium cast steel sample is preheated to 150 DEG C, and the temperature is kept for 1.5 h; (2) the diameter of a laser spot is 3-5.5 mm, the power is 1800-2700 W, the scanning speed is 300-1500 mm / min, the overlap rate is 16.7-50 %, and argon is used as protective gas; (3) two times of tempering at 560 DEG C are carried out after laser processing, and the temperature keeping time is 1 h every time; (4) the initial point and the finishing point in the laser fusing process do not fall on a workpiece. The laser rapid repairing method can fuse high chromium cast steel roller surface layer fatigue micro cracks, a laser fusing layer and a base body are combined in a metallurgy mode, the thickness is 0.4-0.7 mm, the hardness is improved to HV672, the corrosion resistance is improved by three times compared with the base body, and the high temperature abrasion resistance at 560 DEG C and 650 DEG C is obviously improved compared with the base body.

Description

technical field [0001] The invention relates to a laser rapid repair method for fatigue microcracks on the surface of high-chromium cast steel rolls, which belongs to the innovative technology of material surface treatment methods. This method is applicable to the local repair and strengthening treatment of the surface of the high chromium cast steel hot rolling roll for rolling billet. Background technique [0002] Due to the high content of carbon and alloying elements in high chromium cast steel, the matrix contains a large amount of primary carbides, which has high mechanical strength and wear resistance, and gradually replaces semi-steel and high chromium cast iron rolls, and is widely used as a heat sink. Rough rolling and finishing front work rolls of continuous strip rolling mills, rough and finishing work rolls of wide medium and heavy plates, finishing rolls of small section steel and bar mills, etc. However, the primary carbides in the high-chromium cast steel ma...

AI Technical Summary

Problems solved by technology

However, the hardened layer obtained by laser phase transformation hardening treatment is relatively shallow, and cracks are prone to appear on the surface, which affects the service life of the roll

The content of the patent (01114853.5) involves the use of laser melting treatment technology to improve the surface properties of cast steel rolls, mainly for high-carbon manganese steel rolls, but it does not solve the problem of repairing micro-cracks on the surface of high-chromium cast steel materials and the problem of laser surface strengthening

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