Steel heat treatment method and system

Abstract

Different from the existing carburizing and quenching process, which cannot significantly increase the area fraction of the martensite structure on the surface of the steel piece, the present invention specifically combines a preheating device, a heating furnace, a quenching device, a hot-pressing device, and a A furnace, and an air-cooled pipe device form a basic structure of a steel heat treatment system. Through the use of the preheating device and the heating furnace, the continuous steel is heated to 800-980° C., which plays the role of quenching and tempering hardening of the continuous steel. At the same time, by using the quenching device (lead bath furnace) of the present invention to quench and temper the continuous steel material, most of the austenite inside the continuous steel material can be transformed into martensite. In the present invention, the continuous steel material is first leveled by using a hot-pressing device to eliminate the internal stress of the continuous steel material due to the quenching process. More particularly, the present invention further utilizes an air-cooled tube device to reduce the temperature of the continuous steel to below 100°C, thereby significantly increasing the area fraction of the martensitic structure on the surface of the continuous steel.

Description

technical field [0001] The present invention relates to the technical field of heat treatment applied in metal processing, especially to a steel heat treatment method and system, which are used to perform continuous processing such as quenching and tempering, quenching, and tempering on a continuous steel, and then improve the continuous steel hardness. Background technique [0002] The carburizing process is used to process low carbon steel into high carbon steel. The specific method is to place the low-carbon steel workpiece into a heating environment with a carburizing medium (such as methane, ethane, etc.), and use high temperature to heat the low-carbon steel workpiece to make it austenitized (Austenite). ). It is worth noting that during the transformation of the surface layer of the low-carbon steel workpiece into an austenite structure, the carbon atoms decomposed by the carburizing medium will penetrate into the surface layer of the steel piece, increasing the car...

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Problems solved by technology

[0011] (1) Although the five process steps can shorten the process time of carburizing treatment, the carbon content of the steel part is limited to less than 0.6wt% instead, resulting in restrictions on the application of the semi-finished steel part to the finished product;

[0012] (2) Although the secondary quenching process can transform part of the bainite (Pearlite) into fine bainite (FinePearlite), it cannot significantly increase the area fraction of the martensite structure on the surface of the steel. The effect of improving the surface hardness of steel parts is limited

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