No-hydrogen atmosphere protection heat treatment process completely without decarburization for steel

Abstract

The invention discloses a no-hydrogen atmosphere protection heat treatment process completely without decarburization for steel. CO2 is fed in a gas generation furnace with activated carbons, and is chemically reacted with the activated carbons; a reaction product a is fed in a sealing atmosphere furnace with workpieces to be thermally treated; then, N2 is fed in the sealing atmosphere furnace to dilute the reaction product a; the contents of the reaction product a and N2 in the sealing atmosphere furnace are adjusted through comparing a set value of a carbon controller with a carbon potential measurement value in the atmosphere in the sealing atmosphere furnace to form a no-hydrogen protection atmosphere; the workpieces can be located in the no-hydrogen environment in the heating and insulation process of the heat treatment; the carbon potential in the atmosphere is always kept the same with the carbon content of the workpieces in the furnace; the workpieces generate no decarburization or recarburization through long-time stop under high temperature; the complete protection of the steel in the no-hydrogen environment is realized; and the decarburization problem of large and ultralarge workpieces manufactured by high-strength steel and ultrahigh-strength steel in the heat treatment in the field of aerospace is solved.

Description

technical field [0001] The invention relates to the atmosphere protection of heat-treated steel of metal materials, in particular to a heat-treatment process method capable of keeping steel parts in a hydrogen-free environment and without decarburization during the heating and heat-preservation process of the heat treatment. Background technique [0002] In the process of heat treatment of steel parts, in order to prevent decarburization and oxidation of workpieces at high temperatures, vacuum heat treatment is generally used or treated in a sealed atmosphere furnace using a protective atmosphere. Commonly used protective atmospheres include inert atmosphere (such as nitrogen, argon, etc.), nitrogen-methanol atmosphere, methanol cracking gas, RX gas, nitrogen-based atmosphere, etc. [0003] The inert gas will not react chemically with the workpiece material at high temperature, but usually the inert gas inevitably contains other impurity gases, such as O 2 , CO 2 、H 2 O ...

AI Technical Summary

Problems solved by technology

This kind of atmosphere is mainly high-purity inert gas, adding a small amount of constant CO, and the atmosphere does not contain hydrogen. It also has a certain effect on the protection of such parts, but its protection effect on the workpiece is as mentioned above. Oxidation protection is good, but decarburization protection is not very ideal. Generally, the depth of decarburization layer is 0.2-0.3mm, and the loss of carbon element in the decarburization layer is serious, and the hardness and strength drop significantly.

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