Surface reinforcement (also known as pressurization) of steel balls is within the elastic-plastic deformation range of the surface of steel balls. The collision of the steel ball will cause the macroelastic deformation and microscopic plastic deformation of the surface, which can increase the hardness of the surface of the steel ball, improve the uniformity, and strengthen the surface through the compressive stress distribution. When ball bearings work, fatigue cracks are easy to occur at a large shear stress depth below the surface, and then microcracks are propagated to the surface under the action of alternating stress, causing fatigue disengagement.
The steel ball surface strengthening process generates residual compressive stress at a large shear stress depth, eliminates the tensile stress conducive to the formation and propagation of microcracks, converts the tensile stress on the surface of the steel ball into compressive stress, and improves and improves the fatigue strength and wear resistance of the steel ball. Bearing life assembled with rebar more than doubles.
The surface strengthening method of steel ball is achieved by the surface heat treatment method of steel ball, and the commonly used methods of surface strengthening include surface heat treatment and surface mechanical treatment. Heat treatment and pre-quenching change the metallographic structure on the surface of the steel ball, making it more evenly distributed. If the diameter of the steel ball is less than 10mm, the surface hardness can be increased by about 05HRC-2HRC. If the diameter of the steel ball is 10mm, the hardness of the steel ball surface material increases by about 15HRC-3HRC. The surface hardness of steel balls is very good for improving the contact fatigue life of metals. The reinforced surface of the ball shows the compressive stress state associated with the cold plastic deformation of the metal. When the metal is plastically deformed at low temperatures, the crystal lattice is twisted, stretched or broken, many atoms are detached from the original dense atomic arrangement, the metal becomes less dense, the volume of the underground and the metal have no plastic deformation, it has elasticity, which can prevent the volume of the surface gold house from increasing, so that compressive stress is applied to the surface metal.