Production method of steel for high-strength saw blade for mines

Abstract

The invention discloses a production method of steel for a high-strength saw blade for mines. The process route comprises the steps of molten iron pretreatment, converter smelting, LF furnace treatment, VD vacuum treatment, continuous casting, heating, rolling, off-line quenching, tempering and performance inspection. The steel comprises the following chemical components in percentage by weight: 0.17-0.20% of C, 0.17-0.37% of Si, 1.40-1.60% of Mn, 0.05-0.12% of Ti, 0.0010-0.0020% of B, less than or equal to 0.015% of P, less than or equal to 0.003% of S, 0.02-0.040% of Als and the balance of Fe and inevitable impurities. The plasticity and the welding performance of the steel are good, the yield strength Rp0.2 of a finished steel plate after tempering is larger than or equal to 1000 MPa, the tensile strength Rm is larger than or equal to 1200 MPa, the ductility A50 is larger than or equal to 18%, the surface hardness of the whole plate is 32.0-37.9 HRC, the impact energy value at the temperature of 0 DEG C is larger than or equal to 100 J, and the requirements of the steel for the high-strength saw blade for the mines are met.

Description

technical field [0001] The invention belongs to iron and steel smelting technology, in particular to a production method of steel for high-strength saw blade matrix used in mining. Background technique [0002] Saw blade steel for mines is made of high-strength and high-wear-resistance 2.0~16.0mm hot-rolled thin plates or medium-thick plates, which must have high strength, high hardness and certain toughness. The traditional production method of circular saw blade steel for mining is: the rolling mill is responsible for the production of plates for saw blades, and the saw blade manufacturer processes it into a disc body. After the processing is completed, a circle of saw teeth is welded around the saw blade steel. saw blade. For saw blades with a diameter of less than 2000mm, they are produced by hot rolling mills, while those with a diameter of more than 2000mm are produced by tailor welding or rolling by medium and heavy plate rolling mills. In order to ensure the perfor...

AI Technical Summary

Problems solved by technology

In order to ensure the performance of the saw blade steel substrate, oil quenching and quenching heat treatment is required, generally including pretreatment, quenching heating and cooling treatment, which has complex heat treatment process, high requirements for treating agent and quenching agent, high cost, and large oil quenching smoke is harmful to the environment Disadvantages such as unfriendliness

[0003] At present, the commonly used materials for mining saw blade steel are 75CrL, 65Mn, 52Mn2V, etc., all of which are mainly composed of high carbon and high alloy components, with high strength and high rigidity, but poor plasticity and toughness, and high alloy cost.

Steel with high carbon equivalent is not easy to weld in the production of saw blades, and cracks are prone to occur during processing and use, and the service life is short

And the addition of Mo, Cr, and Ni alloy elements will form an oxide scale with strong adhesion on the surface of the steel plate, which will affect the surface quality of the saw blade steel and increase the subsequent grinding cost

[0004] Chinese patent "CN102296243A "a diamond saw blade substrate steel and its production method" discloses the chemical composition: C: 0.67%-0.75%, Si: 0.17%-0.37%, Mn: 0.9%-1.20%, Cr: 0.4% ~ 0.7%, Ni≤0.25%, Cu≤0.2% heat-treated medium and thick plate, high carbon content and contains Ni and high Cr elements, the cost of the alloy is high, and defects such as segregation are prone to affect the use life, while containing a certain amount of Cu is not conducive to the control of cracks on the surface of the slab

[0005] Chinese patent CN104178691A "A high-strength metallurgical saw blade steel and its manufacturing method" discloses chemical composition: C: 0.30% to 0.60%, Si: 0.15% to 0.30%, Mn: 1.35% to 1.9%, V: 0.070 %~0.19%, Al: 0.025%~0.055% heat-treated steel plate, after quenching and tempering, the hardness of the finished steel plate is 28-40HRC with a large fluctuation range, which is not suitable for direct processing to produce saw blade substrates with a diameter of more than 2000mm

[0006] Chinese patent CN 106319378 B "a large-diameter thin saw blade base steel and its manufacturing method" discloses chemical composition: C: 0.72%-0.95%, Si: 0.06%-0.40%, Mn: 0.5%-0.95%, Cr: 0.10% ~ 0.39%, V: 0.03% ~ 0.080%, Ni≤0.5%, and H≤0.0002%, impurity elements P≤0.015%, S≤0.010% and Al≤0.010% heat-treated steel plate, its C, The Mn content is extremely high, which is not conducive to the welding of the cutter head. At the same time, the content of Cr and Ni precious alloy elements is high, and the alloy cost is high.

The C content is high and contains 0.07-0.19% V, which is not conducive to the control of cracks in the continuous casting slab. The final cooling temperature of quenching requires 200~300°C, which is difficult to actually control in the production of medium and thin gauge plates.

[0008] Some deficiencies in the steel types mentioned in the above documents and inventions do not meet the development requirements of the current mining saw blade industry

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