Method of corrosion nitriding parts made of steel 40x

 

(57) Abstract:

The invention relates to mechanical engineering and can be used for mass production of steel parts from corrosion nitriding. The objective of the invention is to develop multiformeingegno method corrosion nitriding, simplifying the implementation of this method, the hardening of parts and mass production of heat-treated parts. This method includes a hardening heat treatment and nitriding, and the semi-finished product made with an allowance under mechanical processing, perform hardening heat treated by normalizing, made experimental details, then attirbute determine the sizes before and after nitriding, assess changes in the size of the experimental details, and then make batches of parts with regard to resize an experienced parts and their attirbute. The technical result of the present invention is to create a reliable technology of hardening and corrosion protection, providing small deformation, the mass production of parts by reducing the cycle time of manufacturing. table 2.

The invention relates to mechanical engineering and can be used in massorah used in mechanical engineering. The nitriding are part having final dimensions. The thickness of the corrosion-resistant diffusion layer is usually from a few micrometers to tens of microns. Additional hardening of parts nitriding complete quenching with rapid cooling and subsequent vacation: "the Metallography and heat treatment of steel and cast iron. The Handbook. M: Metallurgizdat. 1956. S. 626.

This method is adopted for the prototype.

The disadvantages of the prototype: hardening directly into the nitriding furnace or furnace with rapid cooling is difficult, with a sudden cooling violated the dimensions of the parts due to warping, significant volumetric deformation during hardening of the core parts, which is difficult to predict and take into account.

The objective of the invention to develop a method multiformation, facilitate its implementation, providing the hardening of parts and mass production of heat-treated parts.

The problem is solved by replacing the induction hardening preliminary normalization of the material with subsequent corrosion nitriding details.

Common symptoms with prototype: running hardening heat treatment and corrosion AZ is e air) additional hardening create nitriding of the workpiece surface (compressive stresses diffusion layer).

To implement the method perform the operations of:

1. Make cake mix with an allowance under mechanical processing.

2. Perform normalization (hardness 23...30 HRC_e).

3. Make experimental details, determine their sizes, attiret, again determines the size and appreciate the "swelling" (resizing).

4. Make batches of parts with regard to "swelling" of sizes and attirbute.

5. Control the thickness of the corrosion phase (Microlife samples or details), the hardness and the absence of the fragility of the diffusion layer, the dimensions of the parts.

The method is tested practically in the manufacture of the casing perforators of steel 40X using a normalized semi-finished products (table. 1) and corrosion nitriding parts (PL. 2).

Before nitriding is performed degreasing in a hot alkaline solution with washing and drying. Nitriding is conducted in a furnace "OKB" at a temperature of 600^oWith aged 1 hour.

Details were grey with patches of flowers of discolouration. Corrosion of ocuparea (copper is not deposited) and exposure in tap water a day (corrosion is not detected). The thickness of the phase is equal to 6...12 μm, the total thickness of the corrosion layer to 160 μm. The microhardness of the core parts is equal to 264 HV 0,1, -phase 579 HV 0,02.

The technical result is to create a reliable technology of hardening and corrosion protection, providing small deformation, the mass production of parts by reducing the cycle time of manufacturing, because the normalization simplifies and reduces the heat treatment allows to automate the process, to repeal mandatory testing hardness of each part (if normalization does not occur fragile structure of martensite). Nitriding can be performed large manufacture at the same time.

Method of corrosion nitriding parts made of steel 40X, including hardening heat treatment and nitriding, characterized in that the manufactured semi-finished product with an allowance under mechanical processing, perform hardening heat treated by normalizing, made experimental details, then attirbute determine the sizes before and after nitriding, assess changes in the size of the experimental details, and then make batches of parts with regard to resize an experienced parts and their attirbute.