Bar for large wind driven generator gear and manufacturing method of bar

Abstract

The invention relates to a preparation method of gear steel, in particular to a bar for a large wind driven generator gear and a manufacturing method of the bar. The bar comprises the following components of: 0.37-0.42 percent of C, 0.15-0.40 percent of Si, 0.80-1.25 percent of Cr, 0.50-0.90 percent of Mn, 0.15-0.30 percent of Mo, not more than 0.015 percent of S, 0.02-0.04 percent of Al, not more than 0.0015 percent of O, not more than 0.00020 percent of H, not more than 0.012 percent of P and the balance of Fe and unavoidable impurities. The manufacturing method comprises the steps of: adopting EAF (Electric Arc Furnace) and LF (Low Frequency) refining and VD (Vacuum Degassing) smelting, controlling aim carbon, aim phosphorus and tapping temperature of the electric arc furnace, adding synthetic slag, silicomangan and compound medium aluminum in a ladle in the tapping process for pre-deoxidizing; carrying out argon stirring in a refining process, fully deoxidizing, desulfurizing, removing impurities; treating for at least 10min under the vacuum degree of less than 0.5 torr of a VD furnace, feeding an Al wire after the vacuum is broken to control the content of the Al in the steelto be between 0.02 percent and 0.04 percent; and executing full-protection and low superheat degree pouring on continuous casting, adopting a medium-strength soft-pressing process on the solidified tail end, and adopting a heavy-pressing for carrying out rolling. The bar disclosed by the invention has high purity and compactness, and adapts to a complex and severe working environment of a wind power gear.

Description

technical field [0001] The invention belongs to the field of metallurgy, and relates to a preparation method of gear steel, in particular to a large-scale wind power generator gear bar and a preparation method thereof. Background technique [0002] The working environment of wind turbine gears is very complex, with frequent alternating loads, large impacts, and large changes in ambient temperature, especially in alpine regions rich in wind energy resources. Therefore, special requirements are put forward for the impact toughness of gear steel at low temperature (-40°C). Conventional gear steels such as 20CrMnTi cannot meet the actual working conditions of wind power gears. [0003] The patent application number is: 200810024513.0, and the patent name is: "Gear Steel for Wind Power and Its Preparation Method". : 0.60~1.00%, Mo: 0.15~0.35%, the balance is Fe and unavoidable impurities, and Nb can be added: 0.01~0.10%, the unit is mass percentage, the carbon content of this in...

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Problems solved by technology

[0002] The working environment of wind turbine gears is very complex, with frequent alternating loads, large impacts, and large changes in ambient temperature, especially in alpine regions rich in wind energy resources. Therefore, special requirements are put forward for the impact toughness of gear steel at low temperature (-40°C). Conventional gear steel such as 20CrMnTi cannot meet the actual working conditions of wind power gears

[0003] The patent appl

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