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US 12,644,162 B2Granted
Method for producing a screw, and screw
AssigneeEJOT GmbH & Co. KG
InventorsRalph J. Hellmig, Michael Achenbach, Fabian Simonsen
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AssigneeEJOT GmbH & Co. KG
InventorsRalph J. Hellmig, Michael Achenbach, Fabian Simonsen
Estimating the term…
The invention relates to a method for producing a screw, having the following steps: (a) rolling a screw wire made of low-alloy carbon steel to produce screw (10) having a thread; (b) heating the entire screw (10) to an austenitizing temperature under a carbon atmosphere and/or nitrogen atmosphere and maintaining the temperature; (c) quenching the entire screw (10) to a bainitizing temperature and maintaining the bainitizing temperature until the screw has a bainitic structure over its cross-section. The invention is characterized in that the screw (10) is subsequently hardened locally at its tip (22), by the tip (22) being heated to an austenitizing temperature and the screw (10) being subsequently quenched to a temperature below the martensite starting temperature (MS).
A screw formed from low alloy carbon steel comprising a thread-bearing shaft, a tip, a core and an edge zone, wherein the edge zone of the screw has an edge zone of the thread-bearing shaft and an edge zone of the tip, the thread-bearing shaft consisting of a bainitic structure over an entire cross-section, the edge zone of the thread-bearing shaft having a bainitic structure and a higher carbon content than the core, and wherein at least the edge zone of the tip substantially consists of a hardened martensitic structure, the edge zone of the tip having a higher carbon content than a core of the tip, wherein an alloy content of the low alloy carbon steel is less than 3%.
A screw formed from low alloy carbon steel comprising a thread-bearing shaft, a tip, a core and an edge zone, wherein the edge zone of the screw has an edge zone of the thread-bearing shaft and an edge zone of the tip, the thread-bearing shaft consisting of a bainitic structure over an entire cross-section, the edge zone of the thread-bearing shaft having a bainitic structure and a higher carbon content than the core, and wherein at least the edge zone of the tip substantially consists of a hardened martensitic structure, the edge zone of the tip having a higher carbon content than a core of the tip, wherein the low alloy carbon steel is formed from at least one of 23MnB4 and 38B2 steel.
Dependencies are inferred from the claim text.