143 results about "Maraging steel" patented technology

A pencil-type glow plug for a self-igniting internal combustion engine is described. The pencil-type glow plug includes a plug body in which a combustion chamber pressure sensor is integrated, and a bar-shaped heating element that protrudes out from the plug body at one end, into the combustion chamber of the internal combustion engine. A force-measuring element of the combustion chamber pressure sensor is accommodated behind the heating element, which moves axially under the influence of force. The force-measuring element is sealed against combustion chamber gases by a steel diaphragm made of a stainless precipitation-hardened maraging steel.

The object of the present invention is to manufacture mechanically manipulated rotary tools, preferably drilling, milling, grinding and cutting tools, which have stable corrosion resistance and biocompatibility, but also have high mechanical strength properties and good ductility . For this purpose, the present invention relates to the use of a precipitation-hardening martensitic stainless chromium-nickel steel having the following composition (in wt.-%): chromium: 10 to 14, nickel: 7 to 11, molybdenum: 0.5 to 6, copper: 0.5 to 4, aluminum: 0.05 to 0.55, titanium: 0.4 to 1.4, carbon + nitrogen: up to 0.3, sulfur: less than 0.05, phosphorus: less than 0.05, manganese: up to 0.5, silicon: up to 0.5, tantalum, niobium, vanadium and tungsten: maximum content of 0.2 each, cobalt: up to 9.0 when appropriate, boron: 0.0001 to 0.1 when appropriate, the remainder being iron and usual impurities.

A metal ring made of maraging steel is heated in the presence of a halogen compound gas, so as to eliminate an oxide film from the surface of the metal ring and to form a halogenous compound film. Thereafter, the metal ring is heated under a vacuum or reduced pressure atmosphere to eliminate the halogenous compound film, and then it is maintained under an atmosphere comprising ammonia at a processing temperature ranging between 450 DEG C and 500 DEG C for a processing time ranging between 30 and 120 minutes, so as to carry out a nitriding processing. The above nitriding processing comprises the steps of: placing the above metal ring into a heating furnace and raising the temperature inside the heating furnace to the above processing temperature; introducing a first mixed gas consisting of 50% to 90% ammonia by volume, 0.1% to 0.9% oxygen by volume, and a residual volume consisting of nitrogen into the heating furnace, and maintaining the above processing temperature, so as to form a nitrided layer on the surface of the metal ring; and when the one-third to one-half of the processing time has passed, replacing the atmosphere inside the heating furnace by a second mixed gas consisting of 0% to 25% ammonia by volume and a residual volume consisting of nitrogen, and maintaining the above processing temperature until the remaining processing time passes.