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Applicable models XCMG QY25K5C_2 QY70KC QY50KC QY25K5D_2 QY25KC XCT35_BR QY25K5D_3 QY25K5D_3 QY25K5C_1 QY55KC_1 QY25K5F_1 QY50KC QY50K5C_1 QY25K5C_2 QY25K5F qy25k5c qy25k5d_2 qy30kc qy55k5c_2 qy25k5f_1 qy25k5d_1 qy30kc qy55k5d
XCT80L6 XCT130_1 XCT12 XCT80L6 XCT25L4_S XCA40_M XCA30_JY XCT25L5_3 XCT55L5 XCT110_1 XCT60L6 XCT12 XCT25L5_SR XCT25L5_2 XCT95L7 XCT75L7 QY110K8C  QY95K7C QY110K7C XCT100 XCT75_S QY40KC XCT90 XCT25 XCT25L5_E QY70KC QY40K5C_2 XCT60L6_1 QY75KC QY100K7C QY95KH QY100K6C QY50JW XCT16_1 XCT100_BR  XCT60 QY20K5D QY85KC XCT25 XCT80L5 XCT100 XCT20L5_1 XCT75L6 XCT20L5 XCT80_S XPD36 QY16KC QY16KC QY40K5D_1 QY25K5L XCA40 QY40KD QY80K5D QY70K5D_1   QY50KD QY20K5C XCT50_Y XCT16_Y XCT25L4_Y XCT80_Y XCT60_Y XCT50_Y and other XCT QY RT series models.

The inner surface of the cylinder liner is directly affected by the high temperature and high pressure gas, and always has high-speed sliding friction with the piston ring and the piston skirt. The surface is in contact with the cooling water, resulting in severe thermal stress under a large temperature difference, and is corroded by the cooling water. The side thrust of the piston on the cylinder liner not only increases its inner surface friction, but also causes it to bend. The piston also hits the cylinder liner when the side thrust changes direction. In addition, it is subject to a large installation preload.
The gas pressure produces tangential tensile stress and radial compressive stress on the cylinder wall, and is the largest on the inner surface, all of which are high-frequency pulsating stress.
Due to the great thermal stress caused by the temperature difference between the inside and outside of the cylinder wall, compressive stress occurs on the inner surface and tensile stress exists on the cooling surface under normal temperature. However, under extremely high temperature, the metal near the inner surface will undergo creep plastic deformation, and after cooling, residual tensile stress will be formed on the inner surface. This low-frequency stress caused by starting and stopping changes will cause material fatigue.
The cylinder liner should have sufficient strength, rigidity and heat resistance, as well as good wear resistance. There should be good lubrication and cooling during work.
The cylinder liner is generally made of wear-resistant alloy cast iron containing phosphorus or boron, such as HT25-47, HP-CuCrMo, etc. The inner surface of the cylinder liner is sometimes treated with chrome plating (chrome plating on loose holes, chrome plating on oil storage outlets), nitriding or phosphating to improve wear resistance. The inner surface hardness of the cylinder liner is usually required to be greater than HB200, and has a good match with the hardness of the piston ring. The inner surface should also have appropriate roughness, so that it has a certain oil storage capacity and running-in performance. The inner surface should have sufficient roundness and cylindricity accuracy, and the mounting support facing the center of the inner hole should have high positional accuracy.