Railway freight car brake round pin surface controlled atmosphere heat treatment

Abstract

The invention relates to a railway freight car brake round pin surface controlled atmosphere heat treatment, comprising the following steps of: blowing gases such as nitrogen, methanol, enriched gas and the like into a heat treatment furnace according to a certain proportion during the brake round pin surface heat treatment process, heating the temperature in the furnace to 850-950 DEG C so as to generate cracking reaction of methanol and the enriched gas and form a nitrogen-based nitrogen with a certain carbon potential, and determining the height of the carbon potential in the furnace to adjust the proportion of nitrogen, methanol and the enriched gas, change basic components of the atmosphere in the furnace and control the carbon potential in the furnace. Therefore, it is ensured that the depth of the brake round pin carbon-free surface layer is controlled within technological setting value. The heat treatment method is safe, applicable, economical and energy saving. The atmosphere in the furnace is easy to control. The technology is easy to operate. And brake round pin surface heat treatment decarburization degree can be effectively controlled.

Description

technical field [0001] The invention relates to a controllable atmosphere heat treatment of metal parts, in particular to a controllable atmosphere heat treatment of the surface of a railway freight car brake round pin, which is mainly used for the heat treatment of the depth control of the decarburization layer on the surface of the railway freight car brake round pin workpiece. Background technique [0002] The railway freight car brake round pin is one of the key parts connected by the levers of the railway freight car foundation brake device, and plays an important role in the process of vehicle braking and relief. With the great increase of the running speed of railway wagons, higher requirements are put forward for the connection quality of brake round pins. At present, the "Technical Conditions for Brake Flat Hole Round Pins and Round Pins for Railway Freight Cars" has put forward new requirements for the performance and quality of brake round pins. To make brake roun...

AI Technical Summary

Problems solved by technology

[0003] The existing heat treatment process generally has the defects of easy deformation, high brittleness and easy oxidation and corrosion, which leads to the oxidation of the surface of the brake round pin workpiece during the heat treatment process, which reduces the carbon content of the surface layer and forms a decarburized layer on the surface

Decarburization will increase the critical cooling rate on the surface of the workpiece, and the austenite structure may dec