Cylinder liner and manufacturing method for same

A method of manufacturing a cylinder liner, wherein a cylinder liner having a cylindrical shape and formed of flaky graphite cast iron is cast, a process in forming a cylinder liner inner periphery includes undergoing a first honing process of making an inner diameter of the inner periphery close to that for finishing after cutting, in a second honing process using a grinding wheel two-stage expansion method provided with a first expansion grinding wheel and a second expansion grinding wheel, a surface roughness of the inner periphery being made to have a ten-point average roughness Rz of 1.6 μm or less and a maximum height Rmax of 2.6 μm or less, and the cylinder liner in which the roughness curve of the inner periphery has a plateau honing shape, the ten-point average roughness Rz of the inner periphery pursuant to JIS B0601:1982 is 4.0 μm or less, and an average value of an area ratio of pits generated in the inner periphery is 8% or less being obtained.

A cylinder liner mounted on a cylinder block and formed of flaky graphite cast iron, wherein at least a nitrided layer is provided on an inner periphery of the cylinder liner, and a cross hatching section is formed on the inner periphery, a roughness curve of the inner periphery has a plateau honing shape, a ten-point average roughness Rz of the inner periphery pursuant to JIS B0601:1982 is 4.0 μm or less, and an average value of an area ratio of pits generated in the inner periphery is 8% or less, and

• wherein the cylinder liner has a metal structure in which flaky free graphite is dispersed and crystallized in a cast iron matrix, some of the free graphite present in a surface part to a depth of 20 μm of the inner periphery of the cylinder liner is dispersed such that a part of some of the free graphite reaches to the inner periphery as an exposed part, and the other free graphite present in the surface part of the inner periphery extends to a vicinity of the inner periphery and is dispersed such that a part reaching the inner periphery from an extension part tip of the other free graphite is a covering section formed of a material that constitutes the cast iron matrix.