Nitrocarburizing process and carburizing layer modification method

Abstract

The invention discloses a nitrocarburizing process and a nitrocarburizing layer modification method. The nitrocarburizing process comprises the following steps that S1, pre-cleaning is conducted, specifically, a workpiece is immersed into a cleaning agent; S2, preheating is conducted, specifically, a preheating temperature is 340 DEG C-380 DEG C; S3, salt bath nitrocarburizing is conducted, specifically, the workpiece is put into a salt bath nitrocarburizing agent, a salt bath temperature is controlled to range from 480 DEG C to 530 DEG C, and the salt bath time ranges from 35 min to 45 min; and S4, cooling is conducted, specifically, the workpiece obtained after nitrocarburizing is taken out of a furnace and cooled. After the process treatment, a nitrocarburizing layer is compact and uniform, the appearance color is black and bright, the surface hardness of the workpiece is effectively improved, and the workpiece has excellent wear resistance, corrosion resistance and fatigue resistance.

Description

technical field [0001] The invention belongs to the technical field of metal surface heat treatment, and in particular relates to a nitrocarburizing process and a method for modifying a carburized layer. Background technique [0002] Nitrocarburizing is to infiltrate nitrogen and carbon elements into the surface of the workpiece at the same time, thereby changing the structure of the steel material, and thus changing the strength, friction, formability and corrosion resistance of the steel material under static load and alternating stress. After the workpiece is nitrocarburized, the surface obtains a co-infiltrated structure. In all industrial fields, the application of nitrocarburizing to improve the strength, wear resistance, seizure resistance and corrosion resistance of steel materials has been widely used in technology. [0003] Salt bath nitrocarburizing, also known as liquid nitrocarburizing, is the process of infiltrating nitrogen and carbon into the surface of the ...

AI Technical Summary

Problems solved by technology

However, during the use of the existing nitride salt, the surface of the valve after the salt bath has heat treatment defects such as insufficient cleanliness and roughness, yellowing, blooming, and corrosion. The salt residue needs to be cleaned every hour, which is time-consuming and laborious. At the same time, it is necessary to add regeneration salt to adjust the composition. When the added regeneration salt reacts with the nitrogen salt, a large amount of irritating gas will be generated, polluting the environment

[0004] During the nitrocarburizing process, the nitrided layer is thin and sometimes there are defects such as insufficient hardness or columnar crystals or veins during the nitriding process.

These will cause some nitriding workpieces to have a thin nitride layer or insufficient hardness or brittleness of the nitrided workpiece to become waste products.