Heat treatment method of microalloying mid-carbon cast steel

Abstract

The invention discloses a heat treatment method of microalloying mid-carbon cast steel and belongs to the technical field of mining metallurgical mechanical materials. According to the heat treatmentmethod, the mid-carbon cast steel comprises, by weight, 0.26%-0.35% of C, 0.60%-0.90% of Si, 1.10%-2.00% of Mn, less than or equal to 0.020% of P, less than or equal to 0.020% of S, 0.02%-0.06% of Nb,0.06%-0.16% of RE and the balance Fe. The heat treatment method comprises the step of conducting high-temperature diffusion annealing, normalizing, quenching and tempering and low-temperature treating on the mid-carbon cast steel subjected to rapid cooling treatment after pouring. By means of the heat treatment, the reasonable matching degree of strength, toughness and wear resistance of the mid-carbon cast steel can be guaranteed; the yield strength of the mid-carbon cast steel is greater than or equal to 900 MPa; the tensile strength of the mid-carbon cast steel is greater than or equal to1000 MPa; the fracture surface elongation of the mid-carbon cast steel is greater than or equal to 15%; the fracture surface shrinkage rate of the mid-carbon cast steel is greater than or equal to 30%; the room temperature impact toughness akv of the mid-carbon cast steel is greater than or equal to 60 J / cm<2>; wear resistance is improved by 2.0 times or above that of a same material product; userequirements of a mining metallurgical mechanical part for the high strength, high toughness and wear resistance are met.

Description

technical field [0001] The invention belongs to the technical field of mining metallurgical machinery materials, and relates to a heat treatment method for realizing reasonable matching of strength, toughness and wear resistance of microalloyed medium carbon cast steel. Background technique [0002] Medium carbon cast steel is widely used as structural material in mining and metallurgical machinery, such as the middle trough of scraper conveyor, and its material is mainly ZG30MnSi. Usually each scraper conveyor has more than 100 mid-section troughs, which account for 70% to 80% of the entire scraper conveyor no matter in terms of weight or cost, so the middle troughs are the most used and consumed parts. In terms of structure, the middle groove of each section is generally welded by integrally cast spade plate groove sides, baffle plate groove sides, high-strength wear-resistant alloy middle plates and bottom plates. Among them, the groove side is located on both sides of ...

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Problems solved by technology

[0003] At present, ZG30MnSi is generally used as the channel side material, or alloy elements such as Cr, Mo, Nb, and RE are added on this basis. It is difficult to meet the requirements of large mining height coal mining face compared with the level of more than 15 million tons in foreign countries

The reason is that the strength and toughness of medium carbon is low, or the matching of strength and toughness is unreasonable, such as high strength and low toughness, etc.

[0004] The above-mentioned groove side adopts normalizing + quenching and tempering heat treatment process (Cai Minghua. Research on carbon casting process in SGZ1000 / 3×855 scraper conveyor [J]. Casting Equipment and Technology, 2013, (6): 35-37), and The compositional characteristics of the groove side and the crystallization characteristics of the microstructure, especially the targeted and effective heat treatment method after the addition of alloying elements to the steel, that is, the role of the alloying elements has not been fully exerted

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