| 摘要 |
PROBLEM TO BE SOLVED: To provide a method for producing a cylinder block which is more lightweight and has more reduced in cost than the conventional cylinder block. SOLUTION: A cylindrical auxiliary member 20 is disposed at a bore portion in a metallic mold 10 and metal is poured into a cavity C around the auxiliary member 20 to form a rough cylinder block. The auxiliary member 20 and a part of the rough cylinder block adjacent to the auxiliary member 20 are removed by machining. That is, the rough cylinder block is formed so that the cylindrical auxiliary member is included in the bore portion in the cylinder block and thus, the core portion can be formed without arranging the tapered part. Thereafter, the rough cylinder block together with the auxiliary member are machined to form the bore portion and thus, a linear with a thermal-sprayed layer, is formed in this bore portion. In this case, since the formed bore portion can be formed as a surface having a fixed depth from the casting boundary, the surface which can reduce number of defects, such as blow hole, is obtained.
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