Material: They are usually made of high – quality alloy steel, such as 35MnB, 40MnB, or 50Mn. For example, some track carrier rollers use 50Mn steel, and the surface hardness can reach 56 – 62 HRC.
Surface Hardness and Hardening Depth: The surface hardness is generally in the range of HRC 52 – 58, and the hardening depth is 8 – 12 mm. But different manufacturing processes and heat – treatment methods may lead to some differences.