Improved Cr8 steel roll and preparation method thereof

Abstract

The invention discloses an improved Cr8 steel roll and a preparation method thereof. Based on the Cr5 steel, the Cr8 steel roll also comprises microalloying Nb and RE, wherein Nb is mainly used for refining the crystalline grain, and RE is mainly used for purifying molten steel. The Cr8 steel roll comprises the following components: 0.50-0.65% of C, less than or equal to 1.0% of Si, less than or equal to 0.60% of Mn, less than or equal to 0.020% of S, less than or equal to 0.020% of P, 7.5-8.5% of Cr, 0.70-1.40% of Mo, less than or equal to 0.50% of V, 0.005-0.20% of Nb, 0.003-0.02% of RE, and the balance of Fe and impurities. By combining solidification refining, deformation recrystalization refining and thermal treatment refining, the method refines the tissue of a high chrome ledeburite die steel and obtains fine plate martensite with the length less than 30micron and width less than 0.5micron. Due to rare earth modification, carbide segregation is reduced, and the morphology of the included foreign substances and eutectic carbide is improved. Due to the adoption of proper thermal treatment technology, compared with Cr5 steel, the Cr8 steel roll not only has higher toughness, but also improves the abrasion performance, and greatly prolongs the service life.

Description

technical field

[0001] The invention relates to a preparation method of an improved Cr8 steel roll, which belongs to the technical field of roll steel manufacturing technology. Background technique

[0002] At present, the chromium content of steel for forging rolls is getting higher and higher, among which Cr8 is the development direction of this type of roll materials. This type of roll has been routinely produced in foreign countries. The performance indicators of high-chromium material rolls are not very clear in China. The theoretical basis for formulating production process parameters is still insufficient, and it is difficult to determine the best production process. Therefore, it is still in the trial production stage. .

[0003] Cold rolls are the most basic tools for rolling strips, so the service life of cold rolls has a great influence on the cost of rolled products. Both cold rolling mills and roll manufacturers are making great efforts to improve the wear res...

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