Heat treatment methodfor penetrating non-metallic elements into surface layer

Abstract

The invention discloses a heat treatment method for penetrating non-metallic elements into a surface layer, which comprises the following steps of: introducing non-metal gas with certain pressure,, such as ammonia gas, into a heat treatment furnace in a form of rotational flow; and heating to ensure that gas atoms penetrate into a-Fe lattice interstices of a steel surface along with the rise of furnace temperature; adding oxygen gas when the temperature reaches the required holding temperature of 450-600 DEG C, meanwhile applying certain pressure to the furnace, and ensuring ammonia atoms to penetrate into the deep part of a steel structure under the catalysis of the heated oxygen gas so as to improve the solution strengthening effect of the density of the metal surface structure; keeping warm for 15-20h, then cutting power, reducing temperature and turning off the oxygen gas; and discharging a workpiece when the furnace temperature is reduced to 450-480 DEG C. The invention is characterized in that the distortion of the workpiece is controlled in a very tiny premise, achieves the purposes of improving comprehensive property, such as hardness, strength, wear resistance, toughness, corrosion resistance, and the like of a workpiece surface and solves the technical problems, such as distortion, brittleness, penetration layer, corrosion resistance, environmental protection, and the like ubiquitous in the heat treatment industry.

Description

Technical field: [0001] The invention relates to the surface engineering technology of metal materials, and more specifically relates to the technical field of improving the comprehensive performance of iron-carbon alloy materials by means of heat treatment. Background technique: [0002] Iron-carbon alloy is the most basic industrial raw material, and its quality and quantity are directly related to the foundation of a technologically powerful country. The manufacturing process from iron ore to finished steel is a very complex, onerous and involves many factors such as production cost. How to save energy and reduce consumption, how to improve the utilization rate of steel and the surface properties of manufactured workpieces, and prolong the service life is a very valuable work. [0003] As we all know, the more durable the machine or mold is for the user, the better, so the parts must have higher hardness, strength, wear resistance and corrosion resistance, but for the pr...

AI Technical Summary

Problems solved by technology

The contradiction can only be solved by heat treatment methods. However, at present, many heat treatment processes generally have insurmountable defects, namely deformation, brittleness and easy corrosion, which cause many disadvantages in production and use, such as overall quenching, surface quenching, This applies to processes such as high-frequency, intermediate-frequency treatment, and carburizing

For those with lower temperature, such as nitriding, plasma nitriding, etc., although the deformation is small, due to the passivation of nitrogen atom infiltration, the hardness layer will be reduced (0.05-0.06 mm, but not more than 0.100 mm) and the practical value will drop sharply.

There is also a hard nitriding method in the technology that greatly prolongs the treatment time (5-7 days and nights) to reach a depth of 0.50-0.60 mm, but this method causes damage to the surface of the workpiece due to the long-term heating of the parts in the furnace. The overall deformation occurs, and it needs to be corrected and ground again before it can be shaped

In addition, some new surface treatment technologies such as infiltration of metal elements, steam vacuum ion implantation, etc., are mostly limited in practice due to the shortcomings of complex equipment, technical difficulty, and high cost.

Therefore, the current metal heat treatment technology generally has defects such as easy deformation, brittleness, and insufficient hardness of the treatment layer, which is no longer suitable for the rapid development of machinery and mold industries.

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