Developing a hardening process for steel micro components in a drop‐tube furnace

Abstract

Due to the rising demand for small high-performance products needed in wide sections of applications (for example automotive, micro electronics) the requirements for micro components concerning size scale (miniaturizing), quantity, costs and quality require new micro production processes to be developed. Dealing with the challenges of micro production the Collaborative Research Center 747 (CRC) "Micro Cold Forming" funded by the German Research Foundation was established at the University of Bremen in 2007. One of the elementary process steps during production is the heat treatment. The heat treatment process is responsible for the adjustment of the material properties in order to ensure the ability to form and furthermore to obtain the required mechanical properties. Given the challenges of handling the small and extremely sensitive components with an approximate volume of a cubic millimeter a new heat treatment process has been developed. An integrated 5.5 m high vertical drop-tube furnace enables a short-term austenitisation of steel components during falling. At the bottom of the furnace the quenching takes place by using water or ambient air as quenching medium. By this procedure the hardness of soft-annealed components made of steel quality C100 could be increased from 2196 € 241 HM 0.05/5.0 (revalued 254 € 45 HV 0.005) up to nearly 6700 HM 0.05/5.0 (revalued 1050 HV 0.005).

Effect of Heat Treatment Parameters on the Hardness of Soil Working Parts

“…And the hardness value of 65Mn decreased with the increasing of the tempering temperature within a certain range. When the quenching heating time is over 18min, the hardness value began to decrease if the heating time continuously raised [8].…”