Abstract: A hole-forming and thread-forming screw for screwing into a sheet piece, including a slotted screw head for accommodating a tool, a threaded shank and a tapering hole-forming part having outer sides with a continuous convex-shaped curve along an entire length thereof, ribs running like threads along the hole-forming part being provided. The hole-forming part ends in a rounded, blunt end piece, and the rounded ribs, which chiplessly displace the material of the sheet part, are situated symmetrically opposite one another and have a pitch that is a multiple of the thread pitch.

Abstract: The invention relates to a hole-forming and thread-forming screw for screwing into a sheet piece, comprising a slotted head for accommodating a tool, a threaded shank and a conically tapering hole-forming part, ribs running like threads along the hole-forming part being provided. The hole-forming part ends in a rounded, blunt end piece, and the rounded ribs, which chipless displace the material of the sheet part, are situated symmetrically opposite one another and have a pitch that is a multiple of the thread pitch.

Abstract: The invention relates to a self-tapping drill screw that is screwable into a sheet piece and comprises a slotted head for accommodating a tool, a threaded shank, a slightly conically tapering hole-forming part and a hole-grinding part having a conical piece. The hole-grinding part has a radial shoulder that forms a hole and coaxially surrounds the conical piece, engagable with the sheet piece, in a ring-like manner, has a much larger diameter than the conical piece and merges with the hole-forming part via a rounded annular edge.

Abstract: In a process for the production of a screw comprising a low-alloy carbon steel, having a head, an adjoining holding portion and a functional tip which, in the outer region of limited radial depth, is of a greater hardness than the holding portion, in which the screw body is shaped by pressing and rolling and then the functional tip is subjected to a hardening operation, hardening is effected by momentary heating with a high level of energy transfer and subsequent quenching and is limited to portions of the periphery of the functional tip.

Abstract: The invention relates to a cold-rolled fixing screw consisting of a low-alloy carbon steel with a high degree of deformation according to the ratios of external diameter to core diameter of >1.2 and pitch to external diameter of >0.23, with a self-tapping thread for screwing into materials, in particular plastics. The screw material of said steel screw with a ferritic structure contains additional constituents with a substantially higher carbon content than the carbon that is contained in the ferrite. Said mixed structure has a maximum carbon content of 0.42 weight percent and a maximum grain size that corresponds to at least 2000 grain/mm2, preferably at least 3000 grains/mm2, with a residual stress that is impressed and maintained by the cold rolling process.

Abstract: The invention provides a self-screwthread-forming screw comprising an artificially ageable light metal alloy as the screw material, whose shank is provided with a screwthread having screwthread flanks, and which is distinguished in that in at least one region of the screw by virtue of a differing heat treatment the material has a different structure from in the rest of the screw. The invention also provides a process for the production of a screw having the following process steps: forming the screw by rolling or cutting production of the screwthread geometry, solution heat treatment of the screw, quenching of the screw in water, and artificial ageing of the screw, in which the screw if subjected to differing heat treatment in various portions thereof.

Abstract: A fixing element which comprises carbon-bearing steel and has a hardened functional tip is overall heated to the austenitisation temperature, held at that temperature and then quenched and is then subjected to an annealing operation which is effected by inductive heating and limited to the region of the fixing element, which lies outside the functional tip. In that way the structure of the fixing element comprises in part martensite and in part annealed martensite, wherein the functional tip comprises throughout martensite and the remainder of the fixing element comprises a martensite which is annealed by short-term inductive heating.

Abstract: A fixing element which comprises carbon-bearing steel and has a hardened functional tip is overall heated to the austenitisation temperature, held at that temperature and then quenched and is then subjected to an annealing operation which is effected by inductive heating and limited to the region of the fixing element, which lies outside the functional tip. In that way the structure of the fixing element comprises in part martensite and in part annealed martensite, wherein the functional tip comprises throughout martensite and the remainder of the fixing element comprises a martensite which is annealed by short-term inductive heating.

Abstract: In a process for the production of a screw comprising a low-alloy carbon steel, having a head, an adjoining holding portion and a functional tip which, in the outer region of limited radial depth, is of a greater hardness than the holding portion, in which the screw body is shaped by pressing and rolling and then the functional tip is subjected to a hardening operation, hardening is effected by momentary heating with a high level of energy transfer and subsequent quenching and is limited to portions of the periphery of the functional tip.

Abstract: The invention relates to semifinished and finished products made from special corrosion-resistant precipitation-hardened austenitic steel containing a large amount of intersticially dissolved nitrogen, comprising substantially smooth surfaces. The invention also relates to a method for producing corresponding semifinished and finished items. The aim of the invention is to produce semifinished and finished item and to provide an economical method for the production thereof, combining both solidity and resistance to corrosion. This is achieved by precipitation-hardening areas of the steel material.

Abstract: A screw element with a tool engagement means (5, 6) and a spring element (8) which is formed on the screw element in one piece in coaxial relationship with the screw axis (7) and which with its free edge defines a workpiece contact plane which is perpendicular to the screw axis and which is at an axial spacing from the screw element (1), is distinguished in that the spring element (8) is mounted at the periphery of the screw element, that is to say a screw head (4) or a screw nut, it projects radially beyond the periphery and it forms a workpiece contact means (9) which is disposed outside the periphery and which is in concentric relationship with the screw axis (7).

Abstract: A fixing element which comprises carbon-bearing steel and has a hardened functional tip is overall heated to the austenitisation temperature, held at that temperature and then quenched and is then subjected to an annealing operation which is effected by inductive heating and limited to the region of the fixing element, which lies outside the functional tip. In that way the structure of the fixing element comprises in part martensite and in part annealed martensite, wherein the functional tip comprises throughout martensite and the remainder of the fixing element comprises a martensite which is annealed by short-term inductive heating.

Abstract: A screw connection, which is intended in particular for plastic members comprises a screw and an insert member which is to be nonrotatably fitted into one of the components involved in the connection and which receives the screwthread of the screw in an axial passage. In accordance with the invention the axial passage of the insert member is of a smooth-walled, that is to say screwthread-free, configuration and the screw has a screwthread, which cuts or grooves the female screwthread of the insert member. The screw, like the insert, can comprise an aluminum alloy, in which case however the alloy of the screw is of a substantially greater hardness than that of the insert member.

Abstract: The invention provides a self-screwthread-forming screw comprising an artificially ageable light metal alloy as the screw material, whose shank is provided with a screwthread having screwthread flanks, and which is distinguished in that in at least one region of the screw by virtue of a differing heat treatment the material has a different structure from in the rest of the screw. The invention also provides a process for the production of a screw having the following process steps: forming the screw by rolling or cutting production of the screwthread geometry, solution heat treatment of the screw, quenching of the screw in water, and artificial ageing of the screw, in which the screw if subjected to differing heat treatment in various portions thereof.

Abstract: The invention comprises a self-screwthread-forming screw of corrosion-resistant steel, which screw is partially precipitation-hardened. The invention also concerns a process for producing such a screw in which the screw is firstly shaped by pressing and rolling or by screwthread rolling or cutting or in other known fashion characterized in that the screw is then partially precipitation-hardened.

Abstract: The invention comprises a self-screwthread-forming screw of corrosion-resistant steel, which screw is partially precipitation-hardened. The invention also concerns a process for producing such a screw in which the screw is firstly shaped by pressing and rolling or by screwthread rolling or cutting or in other known fashion characterized in that the screw is then partially precipitation-hardened.