Method for repairing straightening machine supporting roller by flux-cored wire surfacing

Abstract

The invention relates to a method for repairing a straightening machine supporting roller by flux-cored wire surfacing. A surfacing process is performed in four layers; the first layer is a binding layer, and a flux-cored wire comprises the following components in percentage by weight: 0.03 to 0.07 percent of C, 0.3 to 0.08 percent of Si, 0.8 to 1.3 percent of Mn, 16 to 20 percent of Cr, 0.1 to 0.5 percent of Mo and the balance of iron; the second layer is a compression resistant layer, and the flux-cored wire comprises the following components in percentage by weight: 0.06 to 0.12 percent of C, 0.3 to 0.6 percent of Si, 0.8 to 1.3 percent of Mn, 10 to 14.5 percent of Cr, 0.1 to 0.3 percent of V, 0.15 to 0.45 percent of Nb and the balance of iron; the third layer is a crack arrest layer, and the flux-cored wire comprises the following components in percentage by weight: 0.35 to 0.5 percent of C, 0.3 to 0.6 percent of Si, 2 to 2.6 percent of Mn, 2 to 6 percent of Cr, 5.1 to 7.8 percent of Nb, 0.3 to 0.7 percent of V and the balance of iron; and the four layer is a wear-resistant layer, and the flux-cored wire comprises the following components in percentage by weight: 0.45 to 0.55 percent of C, 0.3 to 0.6 percent of Si, 0.8 to 1.2 percent of Mn, 2 to 4 percent of Cr, 0.3 to 0.75 percent of Nb, 0.3 to 0.7 percent of V, 1.8 to 2.2 percent of W, 0.3 to 0.8 percent of V and the balance of iron. By the method, failure forms such as concave pits, cracks and the like can be prevented from being produced on the surface of the straightening machine supporting roller.

Description

technical field [0001] The invention relates to a method for repairing support rolls of a medium-thick plate straightening machine. It belongs to the technical field of metallurgical steel rolling. Background technique [0002] The back-up roll of the leveler is an essential process in the rolling process of medium and heavy plates. With the application of controlled cooling and controlled rolling technology, the temperature of the steel plate after final rolling and accelerated cooling is low (450 ° C ~ 600 ° C), while The yield strength of the steel plate has been greatly improved, so high requirements are put forward for the negative load capacity and strength of the support roll of the leveler. [0003] The manufacturing method of the traditional leveling machine support roll is: 50CrMnMo or 60CrMnMo surface quenching, quenching thickness ≤ 10mm, hardness value HRC42-45, during use, it must be finely ground once every 2 shifts. In just a few days, the support roller of...

AI Technical Summary

Problems solved by technology

The reason is that the working temperature of the support roll of the straightening machine is 450°C~650°C, and it has to bear a lot of pressure. Under the repeated cold and heat fatigue and alternating compressive stress environment, the surface of the support roll of the straightening machine will be deformed after use. Failure forms such as pits and cracks, when the crack depth extends to a certain value to the parent body, the value of repair will be lost, and the whole has to be scrapped. The metallographic structure of the surfacing metal is as follows: image 3

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