Decarburization and recarburization prevented atmosphere protection heat treatment process

Abstract

A decarburization and recarburization prevented atmosphere protection heat treatment process mainly comprises the following steps that N2 with the volume 3-4 times that of a heat treatment furnace is introduced, and air in the heat treatment furnace is exhausted; protective atmosphere is introduced into the heat treatment furnace, the oxygen potential value in the heat treatment furnace is monitored, and the protective atmosphere comprises, by volume, 20.7% of CO2, 19.27% of CO, 42.47% of CH and 77.56% of H2; when the oxygen potential value in the heat treatment furnace reaches 1050, the protective atmosphere is continuously introduced, meanwhile, N2 is introduced for pressure maintaining, the temperature of the heat treatment furnace is controlled to be kept at 750-770 DEG C, and the heat preservation time is 10-12 h; and after the heat preservation time is over, the heat treatment furnace is controlled to be cooled, introduction of the protective atmosphere is stopped, N2 is continuously introduced, the protective atmosphere in the heat treatment furnace is discharged till the heat treatment furnace is cooled to 540-560 DEG C or below, the steel is taken out, and the heat treatment process is completed. The condition of unstable protective atmosphere components is avoided, decarburization and recarburization are avoided, and the heat treatment quality of the steel is guaranteed.

Description

technical field [0001] The invention relates to the technical field of heat treatment, in particular to an atmosphere protection heat treatment process for preventing decarburization and carburization. Background technique [0002] Cold heading wire rod, that is, the round material from the steel factory, needs to go through processes such as factory spheroidizing annealing, pickling phosphorus saponification and wire drawing to improve the plasticity and toughness of the material, meet the individual needs of customers for specifications, and improve the cold heading of the material at the same time. Upsetting performance. In the key process of spheroidizing annealing, the steel is prone to decarburization under high temperature conditions. There are two processes in the decarburization of steel: one is that the C atoms on the surface are oxidized; the other is that the C atoms on the surface are lost, which causes the concentration of C on the surface to decrease. Among t...

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Problems solved by technology

In addition, methanol drip cracking will lead to carbon deposition on the furnace wall, hindering heat radiation conduction, insufficient methanol cracking, resulting in unstable cracking gas components, resulting in decarburization and uncontrolled carbon increase on the surface of materials, which will cause product scrapping

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