24 July 2021 Gear Steel Bar
45MnBH Gear Steel Bar
45MnBH hardenability steel, mainly used in the automotive, railways, ships, construction machinery, the use of special alloy steel, one of the more critical materials, but also for gear steel, is to ensure the safety of the core components of manufacturing materials. In recent years, gear steel is moving in the direction of high performance, long life, stable running of gears, low noise, safety, low cost, easy processing and many varieties.
Hardenability is one of the important performance indicators of gear steel, it is mainly to ensure that the core of different sizes of the hardness, and is conducive to control gear heat treatment deformation. Control of hardenability and hardenability bandwidth of gear steel depends mainly on the chemical composition and its homogeneity. That is, the hardenability of large elements such as carbon, manganese and other control, according to the steel carbon and alloy elements on the hardenability of the hardness value of each point to determine the scope of the steel control components.
The presence of oxides and sulfide in steel, harmful elements such as nitrogen, hydrogen, oxygen, etc., will reduce the mechanical properties of steel, deterioration of the steel performance, thus affecting the service life of car carburized gears.
At present, the domestic and foreign requirements on the oxygen content of gear steel are controlled below 20 × 10-6, the international advanced level is below 12 × 10-6, while some domestic special steel plants have reached below 15 × 10-6.
Grain size is an important indicator of gear steel. Fine and uniform austenite grains in gear steel are obtained after quenching to obtain fine martensite structure, which obviously improves the fatigue performance of gears and reduces the deformation after gear heat treatment. Gear steel grain size requirements of ≥ 6, usually in the control of steel smelting residual aluminum content to achieve grain refinement.