| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a fracture split connecting rod, wherein fracture splittability and machinability are satisfactory, and the forging finishing temperature capable of sufficiently securing hardness after forging is made low, thus variation in the proof stress of parts is reduced, and forging efficiency is satisfactory. <P>SOLUTION: In the composition of a non-heat treated steel serving as the constituting stock of the fracture split connecting rod 1, sufficient proof stress and fracture splittability are secured by optimizing the contents of C, V, P and Ti. By making the content of Ti lower than the content level in the conventional non-heat treated steel for a fracture split connecting rod, the forging finishing temperature for sufficiently securing hardness after forging is made lower, and the fracture split connecting rod in which variation in the proof stress of parts is reduced, and forging efficiency is also satisfactory is achieved. On the other hand, by optimizing an Mn content and an S content, an MnS forming amount in the steel structure contributing to the improvement of machinability is increased, and, cutting to a connecting rod shape after forging is efficiently performed. <P>COPYRIGHT: (C)2010,JPO&INPIT |
