Surface Hardening

The combination of a hard surface and a soft interior is greatly valued in modern metal engineering because it offers very high stress and fatigue for applications such as gears and anti-friction bearings. Surface-hardened steel is also valued for its low cost and superior flexibility in manufacturing.
Surface hardening is the treatment of metallic materials by heat or mechanical means to increase the hardness of the outer surface while the inner core remains relatively soft. Most common surface hardening techniques include transformation hardening and shock hardening. Transformation hardening refers to the heat-treatment process which the surface layer is heated above the critical temperature Ta to austenitize and during subsequent quenching hard martensite is formed. The temperature of the heated material reaches the phase transition point, but melting does not occur. The inside core temperature being at below the Ta, it is remaining unhardened and so softer. A high-power laser beam irradiation is usually used to heat the materials. Compared to conventional heat treatment, the laser modification process induces an increase of 15–20% in the hardness of the material. For shock hardening, a high-strength shock wave or stress wave is applied on the metal surface, and then a strong plastic deformation occurs. In the impacted zone, the microstructure of the material shows a network of dislocation tangles, which is similar to the substructure produced by an explosive shock or fast plane shock, significantly improving the surface hardness, yield strength, and fatigue life of the material. Transformation hardening relies on the thermal properties of materials, while shock hardening relies on the dynamics properties of materials. Besides above means, another approach to surface hardening consists of changing surface chemistry.

Matexcel conducts surface hardening treatment for all kinds of metals, including steel, aluminum, titanium, superalloy, composite, etc. Our scientists are experienced with all technologies, and provide relevant supporting research directions and batch production capability of surface hardening metallic products.

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