Surface treatment of MIM- steam treatmen

Surface treatment of MIM (powder injection molding) steam treatment is through the pressure of steam and in the range temperature (such as 550-570 degree ) for a period of time, make the oxide films on the iron-based surface , which prevent iron further corrosion; General process of steam treatment is the removal of oil ,then water washing, then pickling, then water washing (surface is dealt with in the smooth state)  then loaded furnace steam treatment (1-2) and oil immersion treatment; steam treatment need to spent a long time and large energy consumption, temperature and pressure change can produce iron oxide, Fe2O3, or the Fe3O4 ;  if it has dark red on the surface after steam treatment which means the parts have been corroded.

For the expansion of steam treatment, which can increase of the powder metallurgy parts hardness and brittleness; Through the adjusting the temperature or pressure not sure to solve the problem; Fe3O4 can seal the micro-hole and maybe change the local structural through expansion; steam treatment’s loading, due to product overlap, some products can appear grow dim in visible or invisible.

Original article link：

http://www.zcmim.com/article/mim-powder-injection-molding-stom_1.html