The bimetallic cylinder liner is composed of two types of metals: the inner and outer. The outer jacket is made of high-quality carbon steel, and the inner cylinder is made of high chromium wear-resistant alloy iron. After heat treatment, the hardness of the inner cylinder reaches HRC62 or above, and the inner surface is smooth and mirror like. The size tolerance of the inner hole is strict, and the normal service life can reach over 800 hours. The monthly sales volume can reach 300 pieces.