PARTS AND JIG FOR GAS CARBURIZING FURNACE EXCELLENT IN CARBURIZING RESISTANCE AND HIGH-TEMPERATURE OXIDIZING RESISTANCE

摘要

PROBLEM TO BE SOLVED: To provide parts and jigs which are stably usable for a long time in a gas carburizing furnace severe in a thermal shock by performing chromizing treatment and providing a chromium cementation layer in which the chromium concentration of the outermost surface is in a specified range on the surface. ;SOLUTION: A chromium cementation layer of ≥40 wt.% in chromium concentration is provided on the outermost surface of parts. Preferably, the hardness of the chromium cementation layer is 400-2000 mHv and the thickness is 10-200 μm. In chromizing treatment, a cementation agent in which iron-chromium alloy powder of 55-70 wt.% in chromium concentration or 40-80 wt.% chromium powder, 20-60 wt.% alumina, 0.1-2.0 wt.% ammonium chloride powder of a cementation promoting agent are mixed and a material to be treated are filled in a semi-closed container, heated and kept in a heating furnace at 900-1200°C for 5-20 hours while the inside of the container is maintained in an inert gas such as an argon gas or in a reducing gas atmosphere such as a hydrogen gas. The chromizing treated parts are improved in carburizing resistance and are hardly carburized and stable even when they are used for a long time.;COPYRIGHT: (C)1999,JPO