摘要:
A steel which is excellent in delayed fracture resistance containing, by mass%, C: 0.10 to 0.55%, Si: 0.01 to 3%, and Mn: 0.1 to 2%, further containing one or more of Cr: 0.05 to 1.5%, V: 0.05 to 0.2%, Mo: 0.05 to 0.4%, Nb: 0.001 to 0.05%, Cu: 0.01 to 4%, Ni: 0.01 to 4%, and B: 0.0001 to 0.005%, and having a balance of Fe and unavoidable impurities, the structure being a mainly tempered martensite structure, the surface of the steel being formed with (a) a nitrided layer having a thickness from the surface of the steel of 200 µm or more and a nitrogen concentration of 12.0 mass% or less and higher than the nitrogen concentration of the steel by 0.02 mass% or more and (b) a low carbon region having a depth from the surface of the steel of 100 µm or more to 1000 µm or less and having a carbon concentration of 0.05 mass% or more and 0.9 time or less the carbon concentration of the steel.
摘要:
Die Erfindung betrifft eine Behandlungsanordnung (1) für ferromagnetische Teile, insbesondere Schrauben und Muttern, umfassend wenigstens ein Behandlungsrad (3) mit wenigstens einem Magneten zum Halten der ferromagnetischen Teile (5, 5') am Umfang des Behandlungsrades, eine Zuführvorrichtung (7) zum Zuführen der ferromagnetischen Teile zum Behandlungsrad und zum Platzieren der ferromagnetischen Teile auf eine erste Umfangslinie des Behandlungsrades, eine Behandlungsvorrichtung (13) zum Behandeln der ferromagnetischen Teile und eine Abführvorrichtung zum Entfernen der ferromagnetischen Teile vom Behandlungsrad (3) und ist dadurch gekennzeichnet, dass das Behandlungsrad wenigstens eine weitere Umfangslinie zum Halten der ferromagnetischen Teile umfasst und dass die Behandlungsanordnung (1) ferner Mittel (11, 15, 17, 19) zum Transferieren der ferromagnetischen Teile von der ersten Umfangslinie des Behandlungsrades zu einer zweiten benachbarten Umfangslinie des Behandlungsrades umfasst.
摘要:
Gegenstand der vorliegenden Erfindung ist ein Befestigungselement, wie ein Bolzen oder Nagel, eine Ankerstange, eine Schraube oder eine Niete, welches eine innenliegende Kernzone (14) aus einem relativ harten, kohlenstoffhaltigen Stahl und eine relativ zur Kernzone (14) aussenliegende Randzone (17) aus einem mit einem ersten Legierungsmetall legierten ersten kohlenstoffarmen austenitischen Stahl aufweist. Zur Verbesserung derartiger Befestigungselemente wird vorgeschlagen, zwischen der Kernzone (14) und der Randzone (17) wenigstens eine erste Zwischenzone (15a) aus einem zweiten kohlenstoffarmen Stahl anzuordnen, der eine geringere Härte aufweist, als der Stahl der Kernzone (14).
摘要:
The present invention relates to a method for heat treatment of a columnar work. In order to provide the method for heat treatment of a columnar work being able to attain a high productivity, a reduction of cost, and an improvement of quality, as compared with the prior art, the method for heat treatment of a columnar work of the present invention includes a quench-hardening step (S1) and a tempering step (S2) being carried out after the quench-hardening step (S1), the quench-hardening step (S1) includes a first quench-hardening step (S11) and a second quench-hardening step (S12) being carried out after the first quench-hardening step (S11), the entire region of the columnar work (3) from an outer circumferential surface (31f) to a core thereof (32), or a partial region thereof, is heated up to a temperature not lower than a transformation temperature Ac 3 , and then, the work is quench-hardened.
摘要:
There are provided a steel for warm working, to be subjected to warm working as various structures, components of cars, and the like, a warm working method thereof, and a steel material and a steel component obtainable from the warm working method. [Solving Means] A steel is to have a particle dispersion type fiber structure formed in the matrix by warm working. The steel is characterized in that the total amount of the dispersed second-phase particles at room temperature is 7 × 10 -3 or more in terms of volume fraction, and the Vickers hardness (HV) is equal to or larger than the hardness H of the following equation (2): H = (5.2 - 1.2 × 10 -4 λ) × 10 2 ... (2) when the steel is subjected to any of annealing, tempering, and aging treatments in the as-unworked state under conditions such that a parameter λ expressed by the following equation (1): λ = T(logt + 20) (T; temperature (K), t; time (hr)) ... (1) is 1.4 × 10 4 or more in a prescribed temperature range of 350°C or more and Ac1 point or less. This steel is taken as the steel for warm working.
摘要:
The invention relates to a fastening element, which is made of a carbon-containing steel and has a hardened functional tip. The entire fastening element is heated to an austenitizing temperature, held at this temperature, and is subsequently quenched before being subjected to a tempering process that ensues by inductive heating and is limited to the area of the fastening element located outside of the functional tip. This results in the microstructure of the fastening element being partially comprised of martensite and partially of tempered martensite, whereby the functional tip is comprised of martensite throughout, and the remainder of the fastening element is comprised of a martensite that is tempered by short-duration inductive heating.
摘要:
A screw or a tapping screw, comprising an ultra fine structure steel having ferrite grains of 3 µm or smaller in average grain size and a nitrided layer on a surface part, wherein a strength is increased, a surface hardness is increased, and the surface hardness and an inside hardness are kept in balance, whereby a novel tapping screw and novel general screws can be provided.
摘要:
A high-strength bolt having a bolt tensile strength of at least 1200 N/mm and being excellent in delayed fracture resistance characteristics and its steel product. A high-strength bolt having its head and shank formed of a steel product, wherein the steel product is so regulated in quality that the relation between a bolt tensile strength TS (N/mm ) and a tempering temperature T ( DEG C) satisfies the following expression (1), the relation between the bolt tensile strength TS and a carbon equivalent Ceq (%) calculated from its chemical components satisfies the following expression (2), and a bolt tensile strength by hardening and tempering ranges from 1200 N/mm to 1600 N/mm . TS
摘要:
The invention relates to a fastening element, which is made of a carbon-containing steel and has a hardened functional tip. The entire fastening element is heated to an austenitizing temperature, held at this temperature, and is subsequently quenched before being subjected to a tempering process that ensues by inductive heating and is limited to the area of the fastening element located outside of the functional tip. This results in the microstructure of the fastening element being partially comprised of martensite and partially of tempered martensite, whereby the functional tip is comprised of martensite throughout, and the remainder of the fastening element is comprised of a martensite that is tempered by short-duration inductive heating.