Danmarks Tekniske Universitet

Expanite A/s

Expanite Technology A/s

Elos Medtech Pinol A/s

Marcel A J Somers

Thomas Lundin Christiansen

Thomas Strabo Hummelshoj

Morten Stendahl Jellesen

Thomas Strabo Hummelshøj

Per Møller

Niklas Brinckman Gammeltoft-Hansen

Andreas Frederik Kielsholm Körkel

The present invention relates to a method of oxygen hardening a Group IV metal, the method comprising the steps of: providing a workpiece of a Group IV metal in its final shape; oxidising the Group IV metal over an oxidising duration of at least 10 minutes in an oxidising atmosphere at a first temperature to provide a non-stratified Group IV metal oxide on the surface of the workpiece using a gaseous oxidising species having an upper temperature limit of up to 800° C. wherein the first temperature is in the range of 500° C. and the upper temperature limit of the gaseous oxidising species; diffusing oxygen from the non-stratified Group IV metal oxide into the Group IV metal in an inert atmosphere at a second temperature in the range of 500° C. to 800° C. and at a partial pressure of the gaseous oxidising species of up to 10-4 mbar over a diffusive duration of at least 0.1 hour to provide a superficial diffusion zone comprising oxygen in solid solution. In another aspect, the invention relates to a Group IV metal component comprising a material core having a core hardness and a surface hardness of at least the core hardness +200 HV. The component is obtainable in the method of the invention.

Low temperature titanium hardening

The present invention relates to a case hardened component of a titanium alloy, the component having a diffusion zone of a thickness of at least 50 &#x3bc;l&#x3c4;l, as calculated from the surface of the component, the diffusion zone comprising oxygen and carbon in solid solution and having a distinct phase of a carbo-oxide compound having the composition TiOC, wherein x is a number in the range of 0.01 to 0.99, which diffusion zone has a microhardness of at least 800 HV0.025 and which carbo-oxide compound has a microhardness of at least 1200 HV0.025. In another aspect the invention relates to a method of producing the case hardened component. In a further aspect the invention relates to a method of oxidising a component of a Group IV metal.

Case hardened component of titanium

A method for method for solution hardening of a cold deformed workpiece of a passive alloy containing at least 10% chromium, which method includes dissolving at least nitrogen in the workpiece at a temperature T1, which is higher than the solubility temperature for carbide and/or nitride and lower than the melting point of the passive alloy, wherein dissolution of nitrogen at temperature T1 is performed to obtain a diffusion depth in the range of 50 &#x3bc;m to 5 mm, and cooling the workpiece after the dissolution step at temperature T1 to a temperature which is lower than the temperature at which carbides and/or nitrides form in the passive alloy, wherein the cooling step takes place in an inert gas not containing nitrogen. Further, a member, such as a lock washer for securing bolts or nuts prepared using the method.

Method for solution hardening of a cold deformed workpiece of a passive alloy, and a member solution hardened by the method

The invention relates to a method for method for formation of expanded austenite and/or expanded martensite by solution hardening of a cold deformed workpiece of a passive alloy, which method comprises a first step of dissolving at least nitrogen in the workpiece at a temperature T, which is higher than the solubility temperature for carbide and/or nitride and lower than the melting point of the passive alloy, and a subsequent second step of dissolving nitrogen and/or carbon in the work piece at a temperature T, which is lower than the temperature at which carbides and/or nitrides form in the passive alloy. The invention further relates to a member, such as a lock washer for securing bolts or nuts prepared using the method.

A method of activating an article of passive ferrous or non-ferrous metal by heating at least one compound containing nitrogen and carbon, wherein the article is treated with gaseous species derived from the compound. The activated article can be subsequently carburized, nitrided or nitrocarburized in shorter time at lower temperature and resulting superior mechanical properties compared with non-activated articles and even articles of stainless steel, nickel alloy, cobalt alloy or titanium based material can be carburized, nitrided or nitrocarburized.

Method of activating an article of passive ferrous or non-ferrous metal prior to carburising, nitriding and /or nitrocarburising

The invention relates to case-hardening of a stainless steel article by means of gas including carbon and/or nitrogen, whereby carbon and/or nitrogen atoms diffuse through the surface into the article. The method includes activating the surface of the article, applying a top layer on the activated surface to prevent repassivation. The top layer includes metal which is catalytic to the decomposition of the gas.

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Billund, Denmark

Marcel A J Somers