Preparation method of chromium alloy strip steel backup roll

Abstract

The invention provides a method for preparing a chromium alloy steel strip backup roll, the alloy components of the chromium alloy strip steel backup roll include: C: 0.40‑0.80%, Si: 0.60‑0.80%, Mn: 0.60‑ 0.80%, P≤0.025%, S≤0.020%, Cr:4.00‑8.00%, Ni:0.40‑0.80%, Mo:0.40‑0.80, V:0.20‑0.40%, Nb:0.20‑0.40%, Re≤0.05 %, the rest is Fe and unavoidable impurities; and the preparation method includes melting molten steel in an induction electric furnace of an intermediate frequency furnace and making slag, cleaning the slag out of the furnace, refining in an LF furnace, tapping and pouring to obtain a semi-finished backup roll, and performing sequentially after heat unpacking After annealing, primary tempering and secondary tempering, the finished backup roll is obtained. The preparation method of the chromium alloy strip steel support roll of the present invention adopts casting to prepare the support roll, replaces forging with casting, and through the heat treatment process, the morphology and distribution of carbides can be improved, the crystal grains of the crystalline structure can be refined, and the The wear resistance of the support roll can enhance the tensile strength, impact extrusion toughness and thermal crack resistance of the support roll, thereby improving the comprehensive performance of the support roll.

Description

technical field [0001] The invention relates to the technical field of roll preparation, in particular to a preparation method for a chromium alloy strip steel backup roll. Background technique [0002] The main function of the back-up rolls used in the hot-rolled strip finishing mill is to provide pressure support for the work rolls during the rolling operation. Therefore, the back-up roll must first have better wear stiffness, and secondly, because the back-up roll forms a complex contact line with the work roll during the rolling operation, the long-term contact rolling must have a higher yield strength, excellent friction toughness and Fracture resistance. Therefore, the excellent wear resistance of the roll body, good friction toughness, and strong fatigue and thermal cracking resistance are the necessary conditions for the backup roll. [0003] At present, domestic hot-strip finishing mills use back-up rolls, mostly made of DG-Cr2-DGCr5 forged steel and high-alloy st...

AI Technical Summary

Problems solved by technology

[0003] At present, domestic hot-strip finishing mills use back-up rolls, mostly made of DG-Cr2-DGCr5 forged steel and high-alloy steel. For these traditional back-up rolls, the former is cast to forged, with low yield, long production cycle, and low energy consumption. High, the latter uses more precious alloys and consumes a lot of resources. In addition, the back-up rolls of these materials are affected by the rolling environment and often suffer from alternating bending stresses in the complex contact line with the work rolls. Due to the interweaving effect of the heat conduction and extrusion impact force of the workpiece, friction marks will appear on the working surface of the back-up roll when the rolled workpiece passes, which increases the grinding amount of the roll

[0004] At the same time, the compressive stress on the surface of the backup roll interacts with the tensile stress on the core, and accumulates on both sides of the roll surface under the induction of the alternating bending stress. The thermal cracks caused by stress expansion will eventually lead to the shoulders and peeling off on both sides of the roll surface, which will affect the performance of the back-up roll