PURPOSE: To form a nitrided layer having high abrasion resistance easily in a short time in a method of fusion-nitriding the surface of Al etc. in an inert gas atmosphere, by continuously or intermittently scanning an arc heat source thereby nitriding said surface continuously or in a spotlike manner.
CONSTITUTION: In a fusion-nitriding method of holding the surface of the work 1 such as Al and Al alloy in a fused state for a predetermined time by a heating source such as arc or laser in an inert gas (contg. 0.5W2% N2 gas in an Ar gas) atmosphere and cooling slowly, said inert gas is supplied from a supply pipe 2 to the torch 3 inside and voltage is applied between a tungsten electrode 4 and the work 1 thence the generated arc 5 is scanned continuously at predetermined speeds. In the case of intermittent scanning, the treatment of holding the arc for a predetermined time in a fixed position then interrupting the generation of the arc 5 and scanning the same up to the next treating position is repeated. In this way, the nitrided layer of abrasion resistance is easily formed in a short time.
YAMADA TOSHIHIRO
IBARAKI YOSHIAKI
HIOKI SUSUMU
