NO134492B

• Main Authors: SWOBODA K, BLOECH R, KULMBURG A
• Format: Patent
• Language: English
• Published: 12.07.1976
• Subjects: CHEMISTRY; ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR; ELECTRICITY; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUSMETALS OR ALLOYS; MAKING METAL MALLEABLE BY DECARBURISATION, TEMPERING OR OTHERTREATMENTS; METALLURGY; METALLURGY OF IRON; MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; PLASMA TECHNIQUE; PRODUCTION OF ACCELERATED ELECTRICALLY-CHARGED PARTICLES OR OFNEUTRONS; PRODUCTION OR ACCELERATION OF NEUTRAL MOLECULAR OR ATOMICBEAMS

1365180 Hardening ferrous metal surfaces BOHLER & CO AG Gebr 8 Nov 1972 [23 Nov 1971] 51595/72 Addition to 1347555 Heading C7N In a modification of the process of Specification 1347555, according to which material is surface hardened by scanning with a jet of cold plasma followed by self-quenching to produce a surface zone of metastable austenite, use of greater power input to obtain a deeper zone is permitted by immersing the work in an electrically non- conductive liquid so that the area to be hardened is covered by a layer of uniform thickness which is displaced by the plasma stream. The liquid may be a mineral or silicone oil and may be cooled during the operation. As exemplified, steel 3 containing 0À8% C and of cross-section suitable for making edges for skis was heat treated to a strength of 135 kg/mm2 and then advanced at 830 mm/min through oil 5 having a flash point of 280‹ C and which was cooled by water circulating through copper tubes. The edge of the strip was covered intially with 1 mm. of oil and was subjected to plasma jet 2 from torch 1 operated at 400 watts, whereby a 1 mm. metastable austenite zone was obtained having a micro hardness of 930-940 kgm/mm2 at 100gm.