A heat treatment process for plastic mold steel

Abstract

The invention relates to the technical field of heat treatment, and discloses a plastic die steel heat treatment technology. The plastic die steel heat treatment technology comprises the following steps that firstly, segmented atomizing cooling is conducted, and an atomizer is utilized for cooling a forged workpiece; and secondly, tempering is conducted, and after the temperature is reduced to 300-350 DEG C, the workpiece is subjected to tempering treatment. The plastic die steel heat treatment technology has the following beneficial effects that after the workpiece is forged, the atomizer isutilized for cooling the workpiece, compared with the manner that the workpiece is directly immersed in a cooling pond, the atomizing cooling manner is relatively gentle, after the liquid is sprayed out of the atomizer, the liquid can slowly make contact with the surface of the workpiece, and the liquid is heated and evaporated to cool the workpiece; and compared with direct water cooling, the segmented atomizing cooling speed and uniformity are easier to control, the heat on the workpiece slowly and uniformly gets lost through the segmented atomizing cooling, the situation that the interior and exterior temperature difference of the workpiece is too large is avoided; and accordingly, the workpiece cracking probability is reduced, and the workpiece hardenability and uniformity are improved.

Description

technical field [0001] The invention relates to the technical field of heat treatment, in particular to a plastic mold steel heat treatment process. Background technique [0002] Die steel is a type of steel used to manufacture molds such as cold stamping dies, hot forging dies, and die-casting dies. Plastic mold steel is a type of die steel. It is generally made of tool steel quenched and tempered, and can also be made of alloy tool steel. P20 plastic mold steel is a P20 medium carbon Cr-Mo plastic mold steel imported from the United States. This steel has good machinability and mirror grinding performance, and is suitable for making plastic molds and die-casting low-melting point metal mold materials. At present, P20 plastic mold steel is widely used in various modern industries. The existing heat treatment process of P20 plastic mold steel is to cool first, then normalize, temper and heat up, then quench, and finally temper again; among them, when quenching and cooling p...

AI Technical Summary

Problems solved by technology

The existing heat treatment process of P20 plastic mold steel is to cool first, then normalize, temper and heat up, then quench, and finally temper again; among them, when quenching and cooling plate-shaped workpieces with a thickness greater than 300mm, the existing process Usually, the workpiece is put into the cooling pool, and the workpiece is cooled by oil or water through the liquid in the cooling pool; but because the thickness of the workpiece is relatively large, the cooling rate inside the workpiece is slower than that on the surface of the workpiece, so the surface of the workpiece The temperature difference between the workpiece and the inside of the workpiece will be relatively large during the cooling process. When the surface of the workpiece cools down, the temperature inside the workpiece is still relatively high; at this time, the inner stress of the workpiece is caused by uneven thermal expansion and contraction, resulting in cracks on the surface of the workpiece. Reduced hardenability and uniformity of the workpiece

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