| 摘要 |
PURPOSE:To increase the service life of a metal die and to reduce the production cost by forming the ground organization in the mixed organization of a bainite and austenite with the execution of the heating and rapid cooling at specific temp. and for specific time on the sheet metal forming die made of a spherical graphite cast iron. CONSTITUTION:The die 1 made of a spherical graphite cast iron (a circular die) is held by heating for 0.5-3hr at 830-900 deg.C after its rough working. An austempering is then executed with the rapid cooling by dipping in the salt bath, etc. of 200-400 deg.C quickly and holding for >=0.5hr. It is worked in the regular size by cooling upto room temp. after making it in the mixed organization of austenite and bainite. It is more effective for a scuffing causing to perform a phosphate coating treatment on the surface of the is die. In this way the durable life as to the wear resistance and scuffing resistance improvements of the die is increased and the production cost can be reduced.
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