Alloy cast steel roll and preparation method thereof

Abstract

The invention relates to an alloy cast steel roll and a preparation method thereof, and belongs to the technical field of steel rolling. The roll comprises the following chemical components in percentage by mass: 0.70 to 0.85 percent of C, 0.90 to 1.20 percent of Mn, 1.02 to 1.16 percent of Cr, 0.25 to 0.45 percent of Mo, 0.17 to 0.44 percent of Si, 0.03 to 0.08 percent of V, 0.01 to 0.03 percent of N, 0.04 to 0.10 percent of Nb, 0.04 to 0.10 percent of Ti, 0.02 to 0.08 percent of La, 0.02 to 0.08 percent of Ce, 0.03 to 0.08 percent of Al, 0.005 to 0.015 percent of Ca, 0.002 to 0.006 percent of B, 0.003 to 0.015 percent of Te, less than 0.03 percent of S, less than 0.03 percent of P, and the balance of Fe, wherein the sum of the La and the Ce is more than or equal to 0.06 percent and less than or equal to 0.12. The roll has the advantages that the roll has lower production cost; the comprehensive mechanical property, thermal fatigue property and abrasion resistance of the roll are improved, and the service life thereof is prolonged; the tensile strength reaches 1,200 to 1,280 MPa, the elongation rate reaches 15 to 18 percent, the impact ductility reaches 22 to 25 J / cm<2>, and the hardness reaches 45 to 48 HSD; and the operation rate of a rolling mill is improved.

Description

Technical field [0001] The invention relates to a steel rolling mill roll and a preparation method thereof, in particular to an alloy cast steel roll and a preparation method thereof, and belongs to the technical field of steel rolling. Background technique [0002] Before the development of strip steel rolling mills, alloy cast steel rolls were usually used in billet rolling mills and section steel rolling mills. Due to their high strength, toughness and better bite characteristics, the alloy cast steel rolls were developed in strip hot strip rolling mills. From the beginning until now, it is still widely used in roughing work rolls and vertical rolls. At present, the commonly used alloy cast steel rolls are manganese series or manganese-molybdenum series low alloy steel cast steel rolls. This type of roll is difficult to meet the requirements of modern rolling mills due to low wear resistance, easy roll breakage and high roll consumption. On the basis of manganese or manganese-...

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Problems solved by technology

[0004] Foreign patents WO9400253-A and EP646052-A also disclose a chemical composition containing 1-20% Cr, 0.5-3% B and 1% C alloy rolls, which have excellent wear resistance, but the boron content is too high, which is easy to wear. Brittle borides appear, reducing roll strength and toughness

Foreign patents SE8603987-A and SE464225-B also disclose a 0.5-2.0% C, 0.2-0.7% Si, 0.2-0.7% Mn, 3.0-7.0% Cr, 0.5-2.5% Ni, 1.0-6.0% Mo , 1.0-6.0% V, <5% Co+W alloy roll chemical composition, also has excellent wear resistance, but contains more nickel, molybdenum, vanadium, cobalt and other alloy elements, the production cost of the roll is high, and the chromium Too high content, low roll strength and toughness

[0005] The above-mentioned alloy cast steel rolls all have poor toughness and are easily broken during use.

In order to improve the toughness of the cast steel roll and prevent the roll from breaking during use, the roll blank is often forged first to refine its structure, and then processed into a finished roll, which has the disadvantages of complex process, high energy consumption and low material utilization rate.

In addition, because cast steel rolls are thick and large steel castings, with serious composition segregation, coarse grains, and defects such as Widmanstatten structure and casting stress, their mechanical properties are low. In order to overcome the above defects, high temperature diffusion annealing is required first. , and then normalizing and high temperature tempering, there are disadvantages such as complex heat treatment process, long heat treatment cycle and high energy consumption

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