35MnB steel and preparation method thereof

Abstract

The invention discloses 35MnB steel which comprises the following components in percentage by weight: 0.33-0.36 percent of C, 0.20-0.30 percent of Si, 1.20-1.40 percent of Mn, not more than 0.30 percent of Cr, not more than 0.025 percent of S, not more than 0.025 percent of P, not more than 0.20 percent of Ni, not more than 0.20 percent of Cu, 0.015-0.035 percent of Ti, 0.005-0.0030 percent of B, 0.015-0.035 percent of Al, not more than 20*10<-6> percent of [O] and not more than 35*10<-6> percent of [N], wherein the components are smelted in a rotary furnace, subsequently smelted in an LF ladle furnace, then subjected to RH vacuum degassing and finally cast continuously to obtain an ingot blank. The energy consumption cost for producing the type of steel is lowered fundamentally; loss of an element B of the 35MnB steel is reduced; the yield of ferroboron during a steel smelting process is increased; the stability of hardenability of the 35MnB steel can be improved; in addition, by adopting low superheat degree, electromagnetic stirring and a constant-temperature and constant-speed casting process, segregation of the elements such as C and Mn is alleviated, the components are more uniform and the fluctuation of the hardenability is alleviated.

Description

technical field [0001] The invention belongs to the technical field of special steel smelting, and in particular relates to a crawler chain rail link used for construction machinery such as excavators and bulldozers and military machinery such as tanks, and mechanical parts such as steering knuckles and gears of automobiles that withstand impact and load. 35MnB steel for transmission parts such as machine tool worms and connecting rods with high wear resistance requirements and its preparation method. Background technique [0002] 35MnB steel has good hardenability. After different heat treatments, it can meet a variety of performance conditions and uses. After quenching and tempering, it can be used to manufacture mechanical parts that withstand medium loads and medium speeds; after quenching and low-temperature tempering, it can be used to manufacture bearings. Load, low impact and wear-resistant parts; after carbonitriding treatment, it can be used in various transmission...

AI Technical Summary

Problems solved by technology

[0004] 1. The electric furnace mainly uses scrap steel as raw material for production. The content of impurity elements and residual elements in scrap steel is relatively high, and the controllability is poor

[0005] 2. The production of electric furnace consumes a lot of electricity, which leads to the increase of energy consumption cost of 35MnB steel

[0006] 3. During the electric furnace smelting process, the arc will electrolyze the nitrogen in the air, resulting in a sharp increase in the N content in molten steel. In order to ensure the content of acid-soluble B, it is necessary to add more ferrovanadium and ferrotitanium for nitrogen fixation, which increases the nitrogen fixation capacity. cost and difficulty

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