Nozzle point cold machining process

Abstract

The invention discloses a nozzle point cold machining process. The machining process comprises the following steps of, a mold part is put into a vacuum quenching furnace, and a position with great thickness difference is confirmed; inert gas is introduced through a fan, gas flow and pressure are distributed through a plurality of nozzles, the flow of gas output by each nozzle is adjustable, and the relative interval between an output port of each nozzle and the mold part is adjustable; the thick position of the mold part is cooled in a close-up distance and air flow increasing mode, and the thin position of the mold part is cooled in a far-up distance and air flow reducing mode; and the nozzles are adjusted in cooperation with a temperature detection module, and the temperature difference between the positions of the mold part is kept smaller than the preset temperature difference value till the mold part is cooled to the specific temperature. The nozzles are adjusted according to the positions where the mold parts are placed and have great differences in shape and thickness, the cooling performance of different positions in a furnace body is brought into full play, thick places and thin places can be evenly and rapidly cooled, thermal stress and structural stress generated by temperature difference are reduced, and the quenching machining quality is improved.

Description

technical field [0001] The invention relates to the technical field of quenching processing technology, in particular to a nozzle spot cold processing technology. Background technique [0002] The hearth of the vacuum quenching furnace is mostly designed below the radius of the furnace. For the heat treatment of parts with great disparity in thickness, especially for the heat treatment of parts of mold products, when cooling by conventional methods, the center of the mold parts is thicker and the parts are far away from the furnace nozzle. There will be too slow cooling rate and poor hardenability in places where the thickness is too low; too fast cooling will occur in thinner places, resulting in the transformation of some metallographic structures, resulting in excessive structural stress and thermal stress and cracking , Undoubtedly bring greater difficulties to the heat treatment of mold parts. At present, protective measures such as wrapping, shielding and thickening a...

AI Technical Summary

Problems solved by technology

[0002] The hearth of the vacuum quenching furnace is mostly designed below the radius of the furnace. For the heat treatment of parts with great disparity in thickness, especially for the heat treatment of parts of mold products, when cooling by conventional methods, the center of the mold parts is thicker and the parts are far away from the furnace nozzle. There will be too slow cooling rate and poor hardenability in places where the thickness is too low; too fast cooling will occur in thinner places, resulting in the transformation of some metallographic structures, resulting in excessive structural stress and thermal stress and cracking , undoubtedly brings greater difficulties to the heat treatment of mold parts

At present, protective measures such as wrapping, shielding and thickening are usually taken on the thin parts of the parts to prevent the thin parts from cooling too quickly, and the pressure can also be increased to speed up the cooling rate, so as to fully ensure the hardenability of the thick parts of the mold parts, but It is unavoidable that the thin position is affected by excessive protection such as shielding and thickening, so that the thin position also has poor hardenability and increases the overload of the furnace weight, which also causes problems such as overloading and overloading.

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