Economic type core rod alloy steel and preparation and heat treatment method thereof

Abstract

The invention relates to an economic type core rod alloy steel and a preparation and heat treatment method thereof, belongs to the technical field of alloy steel manufacturing process, and is characterized in that the alloy steel comprises the following main alloy elements by mass percentage: 0.25-0.30% of C, 0.10-0.20% of Si, 1.51-1.62% of Mn, 3.60-4.10% of Cr, 0.20-0.30% of Mo, 0.20-0.40% of V, 0.03-0.05% of Nb, and the balance Fe. The alloy steel preparation process comprises the following steps: preparing materials, smelting, casting an electrode rod, and annealing; then carrying out electroslag remelting, and annealing; followed by carrying out multidirectional forging and direct water cooling; then carrying out two-section type annealing; and finally, carrying out quenching and tempering treatment. The properties of the alloy steel are equal to or exceed those of H13 steel under same conditions. The low-alloying-composition design thought of the alloy steel meets a transformation concept that current Chinese steel enterprises are in urgent need of energy saving, consumption reduction, cost reduction and benefit increase.

Description

technical field [0001] The invention relates to an alloy steel for an economical mandrel rod and a preparation and heat treatment method thereof, belonging to the technical field of alloy steel manufacturing technology. Background technique [0002] As one of the important rolling tools, the mandrel is used to combine with the roll to form a closed annular pass, thereby reducing the diameter and wall of the capillary, eliminating the spiral indentation on the inner and outer surfaces of the perforated capillary, and improving the roughness of the inner and outer surfaces of the empty capillary. degree and straightness. During the rolling process, the mandrel not only bears high rolling pressure and surface friction, but also bears the heat from the capillary (including the heat generated by deformation). In order to be able to withstand greater rolling pressure and higher temperature, the mandrel should have higher strength, hardness, wear resistance and thermal cracking re...

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Problems solved by technology

High-alloy steel is used to manufacture mandrels because of its good high-temperature strength and toughness. However, in the process of use, it often has more than enough strength but insufficient toughness. Some mandrels have a large number of thermal cracks and wear scratches on the surface after being recycled for less than 1000 times. Due to the deep defect, it is impossible to change the car, so it is scrapped, which affects the production of continuous rolling steel pipes, and also increases the cost of steel pipe production and prolongs the production cycle. The large amount of reserves in the enterprise will cause pressure on the capital chain turnover link. If the reserve is insufficient, the emergency mobility of the enterprise will be greatly reduced, which will affect the production plan of the entire enterprise

In addition, due to the high alloy content of high-alloy steel and high-temperature strength, it requires a larger load than seamless steel pipes in the hot rolling and sizing process, and it is difficult for PQF rolling mills and sizing machines to meet production requirements.

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