MANUFACTURE OF CYLINDER BLOCK

PURPOSE:To provide a cast steel cylinder block of high quality generating no blow hole at casting by casting cylinder block pieces divided into small blocks out of cast steel, and thereafter forming these cylinder block pieces into one body by welding. CONSTITUTION:When a cylinder block 1 is manufactured, cylinder block pieces 4a-4c cut into round slices at dividing faces 3 between adjoining two main bearing parts 2, 2 are cast out of cast steel. Adjoining cylinder block pieces 4a-4c are butted with each other, beveling parts are formed, and the beveling parts are welded so as to combine them together into one body. Such cylinder block 1 is manufactured out of cast steel of high Young's modulus, and hence the strength is high and the weight can be reduced due to the high strength. Casting is carried out against every cylinder block piece 4a-4c, and hence generation of blow holes can be restrained.