Low-silicon medium-carbon gear steel suitable for cold forging machining and manufacturing method thereof

Abstract

The invention relates to low-silicon medium-carbon gear steel suitable for cold forging machining and a manufacturing method thereof. The steel comprises, by mass percent, 0.35-0.45% of C, smaller than or equal to 0.08% of Si, 0.30%-0.60% of Mn, 0.20-0.50% of Cr, smaller than or equal to 0.020% of P, 0.010-0.040% of S, smaller than or equal to 0.10% of Cu, smaller than or equal to 0.05% of Ni, smaller than or equal to 0.05% of Mo, smaller than or equal to 0.050% of Al, larger than or equal to 0.005% of N, 0.0005-0.0035% of B, smaller than or equal to 0.010% of Ti, smaller than or equal to 0.0020% of [O], smaller than or equal to 0.15% of (Cu+Ni+Mo) and the balance Fe and inevitable impurity elements Round steel with the specification being phi 45 mm to phi 90 mm is formed, and the size precision is smaller than or equal to +/-0.15 mm. According to GB/T 4162-2008, ultrasonic flaw detection on the interior of the round steel meets the A-level requirement. The outer layer of the section of the round steel is a partial decarburized layer, the depth of the partial decarburized layer is smaller than or equal to 0.5% d of the nominal diameter of the round steel, the core part is a matrix structure, the matrix structure is ferrite and spheroidized pearlite, and the spheroidization rate reaches 90% or above.

Description

technical field [0001] The invention belongs to the technical field of iron-based alloys, in particular to a gear steel and a manufacturing method thereof. Background technique [0002] The cold forging process is a precision plastic forming technology. Compared with the traditional hot forging process, the cold forging process has many advantages such as high production efficiency, good dimensional accuracy, high raw material utilization rate and low production cost, and the cold forging process is particularly suitable for Mass production of special-shaped parts. [0003] The cold forging process has strict requirements on raw materials, and ordinary steel for hot forging is difficult to meet the requirements of the cold forging process for steel. Steel for cold forging must have higher dimensional accuracy and shallower decarburization depth than steel for hot forging, and it is necessary to control the hardness and spheroidization rate of steel after spheroidizing annea...

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Problems solved by technology

[0003] The cold forging process has strict requirements on raw materials, and ordinary st...

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