Preparation method of roller for rough rolling of die steel medium plate

Abstract

The invention provides a preparation method of a roller for rough rolling of a die steel medium plate. The roller is prepared from the alloy components in percentage by mass: 0.50 - 0.60% of C, 0.20 - 0.40% of Si, 0.60 - 0.80% of Mn, 0.60 - 0.80% of Cr, 1.40 - 1.60% of Ni, 0.20 - 0.30% of Mo, 0.10 - 0.20% of Nb, 0.05 - 0.15% of V, less than or equal to 0.03% of P, less than or equal to 0.02% of S, less than or equal to 0.03 - 0.05% of Re and the balance of Fe and inevitable impurities. The preparation method comprises the following steps of smelting molten steel in an intermediate frequency induction furnace and slagging, removing slag and discharging, refining in an LF / VD refining furnace, tapping and pouring to obtain a roller semi-finished product, and sequentially annealing, normalizing and tempering after hot box opening to obtain a roller finished product. According to the preparation method, the roller is prepared in a casting mode, forging is replaced by casting, and the chemical components of the roller, a smelting and pouring process, a heat treatment process and the like are improved, so that a microscopic crystal structure of the roller can be refined, and the yield toughness, the wear resistance and the heat crack resistance of the roller are improved; therefore, the poured roller for the rough rolling is more excellent than a forged steel roller and an AS65I alloy steel roller, and the performance of the roller for the rough rolling of the medium plate can be improved.

Description

technical field [0001] The invention relates to the technical field of roll preparation, in particular to a method for preparing a roll used for rough rolling of medium and thick plates of die steel. Background technique [0002] Due to the operating characteristics of the roughing rolls used in the medium and heavy plate roughing mills, after the slab is heated to remove phosphorus, 1-4 passes of shaping are carried out along its longitudinal direction. And the flattening of the head caused by shearing, so that it is regular and the shape is correct when the rear is rolled. At the same time, initial widening rolling and elongation rolling are required to control the width and length during the finishing rolling of the subsequent finishing rolling mill, and finally lay the foundation for obtaining medium and heavy plates with high dimensional accuracy, good shape and good performance. With the development of medium and heavy plates from ordinary type to finishing type, high...

AI Technical Summary

Problems solved by technology

[0003] At present, the material of rough rolls is also transformed from forged steel to AS65I alloy steel. The former has a long production cycle, low yield, poor wear resistance, and is prone to thermal cracking. The wear resistance of the latter is higher than that of forged steel rolls, but its tensile strength is lower than that of AS65I alloy steel. The forged steel roll is affected by the strong impact and extrusion environment during the rolling operation. The roll neck relief grooves at both ends of the roll body become the accumulation area of ​​the alternating bending stress generated when the roll rotates. The compressive stress generated on the surface of the roll The tensile stress generated by the core and the core also extends and accumulates here, thereby increasing the stress accumulation energy, and gradually causing energy fatigue cracks here. When the roll is overloaded, it is easy to cause a broken roll neck accident, leading to early failure of the roll, and affecting Roll performance, and increased plate production costs