Heat Treatment Method of Cam Shallow Layer Carbonitriding

Abstract

The invention relates to a cam shallow layer carbonitriding heat treatment method. The method comprises the steps of carbonitriding, quenching, cleaning and tempering; a carbonitriding main furnace for carbonitriding is provided with four areas in sequence in the heat treatment direction; the furnace temperature of the first area is set as 910+-10 DEG C; the furnace temperatures of the second and third areas are set as 860+-10 DEG C; the temperature furnace of the fourth area is the same with the quenching temperature, and is set as 810+-10 DEG C; during carbonitriding, the carbon potential is controlled as 1.05-1.15 CP, the ammonia quantity is 250-280 L / h, and the carbon potential is controlled by combining manual adjustment with automatic control; the net band frequency of the carbonitriding main furnace is set as 31-33 HZ; and the time of a cam from entering of the carbonitriding main furnace to quenching is 65-75 min. The method can guarantee an effective hardening layer of the cam in a section of 0.15-0.25 mm; the heart hardness is not beyond 400 HV; the flatness deformation is not beyond 0.1 mm; and the method is suitable for large-scale production.

Description

technical field [0001] The invention belongs to the field of carbonitriding heat treatment, and in particular relates to a shallow carbonitriding heat treatment method of a cam. Background technique [0002] Such as figure 1 and figure 2 As shown, the cam is a part of the electrical switch, the material is S20C, the material thickness is about 2mm, the effective hardened layer requires 0.15-0.25mm, the core hardness does not exceed 400HV5, and the surface hardness is 650-750HV5. The size of the cam has strict requirements, so the fine blanking method is used to form the cam. After the fine blanking of the cam, it needs to undergo carbonitriding heat treatment to meet the requirements of surface hardness, effective hardened layer and core hardness. [0003] The surface heat treatment of the traditional cam uses a box furnace. The box furnace is a periodic furnace with low production efficiency. It is necessary to design and manufacture a specific heat-resistant steel hang...

AI Technical Summary

Problems solved by technology

The surface hardness of the cam does not exceed 750HV, so the carbon potential and ammonia gas flow during the carbonitriding process cannot be too high; secondly, the cam material is thin, and the core is easy to harden, resulting in high brittleness of the parts; in addition, effective hardening The layer interval is relatively narrow, 0.1mm (the effective hardened layer control interval of general parts is 0.2mm)

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