Expert analysis: surface strengthening treatment method of high manganese steel

High manganese steel is widely used in mining machinery, metallurgy and other fields due to its high wear resistance. High manganese steel is prone to thermal cracking before use, and shortcomings such as brittle fracture, cracking and short service life may occur during use. Using surface strengthening treatment can improve the original hardness of high manganese steel products and reduce the initial wear of the products. Common methods are:

1. Surface decarburization technology

Using the mechanism of deformed martensite, it is possible to reduce the surface carbon content of high manganese steel castings to make the surface of high manganese steel castings appear deformed martensite to strengthen high manganese steel and improve wear resistance. The available surface decarburization technologies are:

1 Heating in a reducing atmosphere, the surface decarburization is achieved through the chemical reaction of H2 and the surface matrix.

Fer(C+2H2Fe+CH4

2Ar ion bombardment method: Through ion bombardment in the metalizing furnace, the carbon atoms on the surface of the high manganese steel can be bombarded out. The working gas is industrial pure Ar.

2, surface alloying

1 Using the inlay casting process, by brushing alloy coatings on the surface of the mold, sprinkling ferromanganese powder or pasting alloy cast iron sheets, the molten steel is poured and these materials are melted and welded, which greatly improves the surface of the casting. performance.

2 Use Cr-containing electrodes for surfacing on high-manganese steel to improve wear resistance. The surfacing hardness of chromium-manganese steel surfacing electrodes is about HRC31, and the surfacing hardness of general chromium-molybdenum steel surfacing electrodes can reach ≥ HRC40, chrome-manganese-silicon steel surfacing electrode surfacing hardness can reach ≥HRC50. .

3, shot peening

Through shot peening, a layer of fine grains is formed on the surface of high manganese steel castings to increase the initial hardness of the surface, and also improve the fatigue strength of the parts or prevent stress corrosion damage.

4, explosive hardening

Explosive hardening is an effective method of pre-hardening the surface of high manganese steel parts by exploding with explosives. At present, it is only applied to high manganese steel castings, such as forks on railways and bucket teeth of excavators. And the tooth plate of the jaw crusher, etc., used to increase the hardness of the working surface of the parts and improve the wear resistance.