The present invention relates to the application of at least partially bainitic or interstitial martensitic heat treatments on steels, often tool steels or steels that can be used for tools. The first tranche of the heat treatment implying austenitization is applied so that the steel presents a low enough hardness to allow for advantageous shape modification, often trough machining. Thus a steel product is obtained which can be shaped with ease and whose hardness can be raised to a higher working hardness with a simple heat treatment at low temperature (below austenitization temperature).

The present invention relates to the application of at least partially bainitic or interstitial martensitic heat treatments on steels, often tool steels or steels that can be used for tools. The first tranche of the heat treatment implying austenitization is applied so that the steel presents a low enough hardness to allow for advantageous shape modification, often trough machining. Thus a steel product is obtained which can be shaped with ease and whose hardness can be raised to a higher working hardness with a simple heat treatment at low temperature (below austenitization temperature).

The present invention relates to a method for producing an article out of a maraging steel, wherein the article is successively subjected to a solution annealing and heat treatment, wherein the steel has the following composition in weight percent: C=0.01-0.05 Si=0.4-0.8 Mn=0.1-0.5 Cr=12.0-13.0 Ni=9.5-10.5 Mo=0.5-1.5 Ti=0.5-1.5 Al=0.5-1.5 Cu=0.0-0.05 Residual iron and smelting-induced impurities.

A valve spring which has an excellent fatigue limit is provided. A chemical composition of the valve spring according to the present embodiment contains, in mass %, C: 0.50 to 0.80%, Si: 1.20 to less than 2.50%, Mn: 0.25 to 1.00%, P: 0.020% or less. S: 0.020% or less: Cr: 0.40 to 1.90%, V: 0.05 to 0.60%, Ca: 0.0001 to 0.0050%, and N: 0.0100% or less, with the balance being Fe and impurities. In the valve spring, a number density of V-based precipitates having a maximum diameter ranging from 2 to 10 nm is 5000 to 80000 pieces/μm.sup.3, and a numerical proportion of Ca sulfides with respect to a total number of oxide-based inclusions and sulfide-based inclusions is 0.20% or less.

A steel wire which has excellent cold coiling workability, and which has an excellent fatigue limit when made into a spring is provided. A chemical composition of the steel wire according to the present, embodiment containing, in mass %, C: 0.50 to 0.80%, Si: 1.20 to less than 2.50%, Mn: 0.25 to 1.00%, P: 0.020% or less, S: 0.020% or less, Cr: 0.40 to 1.90%, V: 0.05 to 0.60%, and N: 0.0100% or less, with the balance being Fe and impurities. In the steel wire, a number density of V-based precipitates having a maximum diameter ranging from 2 to 10 nm is 5000 to 80000 pieces/μm.sup.3.

A damper spring which has an excellent fatigue limit is provided. A chemical composition of the damper spring according to the present embodiment contains in mass %, C: 0.50 to 0.80%, Si: 1.20 to less than 2.50%, Mn: 0.25 to 1.00%, P: 0.020% or less, S: 0.020% or less, Cr: 0.40 to 1.90%, V: 0.05 to 0.60%, and N: 0.0100% or less, with the balance being Fe and impurities. In the damper spring, a number density of V-based precipitates having a maximum diameter ranging from 2 to 10 nm is 5000 to 80000 pieces/m3.

The disclosure discloses a spinning process of a magnesium alloy wheel hub, which comprises the following steps: step 1, heating a magnesium alloy bar at 350-430° C. and keeping the temperature for 20 minutes; step 2, initially forging and forming on the bar under a forging press, wherein the forging down-pressing speed is 6-15 mm/s; step 3, finally forging and forming on the bar under a forging press, wherein the forging down-pressing speed is 5-8 mm/s; step 4, stress relief annealing on the final forged magnesium alloy blank; step 5, solid dissolving on the annealed magnesium alloy blank; step 6, taking out the solid-dissolved blank and directly spinning by a spinning machine; step 7, heating treatment and aging treatment. The magnesium alloy wheel hub with excellent performance is obtained by the process, and the spinning process and processing efficiency are greatly improved.

Embodiments of the disclosure relate to a ferritic alloy having excellent ability to withstand nuclear power plant accidents and a method of manufacturing a nuclear fuel cladding tube using the same. The alloy includes iron (Fe), aluminum (Al), chromium (Cr), and nickel (Ni). The nickel (Ni) may be included 0.5 to 10 wt % based on a total amount of the alloy. The chromium may be included 13 to 18 wt % based on the total amount of the alloy. The aluminum may be included 5 to 7 wt % based on the total amount of the alloy.

Extrados structural element made from an aluminum, copper and lithium alloy and method for manufacturing same. An alloy with composition (in wt %) 4.2-5.2 Cu, 0.9-1.2 Li, 0.1-0.3 Ag, 0.1-0.25 Mg, 0.08-0.18 Zr, 0.01-0.15 Ti, an Fe and Si content level less than or equal to 0.1% each, and other element with content level less than or equal to 0.05% each and 0.15% in total, is poured, homogenized, deformed hot, placed in a solution at a temperature of at least 515° C., pulled from 0.5 to 5% and annealed. The combination of magnesium, copper and manganese content with the temperature in solution can reach an advantageous elasticity under compression limit. Products having a thickness of at least 12 mm have, in the longitudinal direction, an elasticity under compression limit of at least 645 MPa and an elongation of at least 7%.

Extrados structural element made from an aluminum, copper and lithium alloy and method for manufacturing same. An alloy with composition (in wt %) 4.2-5.2 Cu, 0.9-1.2 Li, 0.1-0.3 Ag, 0.1-0.25 Mg, 0.08-0.18 Zr, 0.01-0.15 Ti, an Fe and Si content level less than or equal to 0.1% each, and other element with content level less than or equal to 0.05% each and 0.15% in total, is poured, homogenized, deformed hot, placed in a solution at a temperature of at least 515° C., pulled from 0.5 to 5% and annealed. The combination of magnesium, copper and manganese content with the temperature in solution can reach an advantageous elasticity under compression limit. Products having a thickness of at least 12 mm have, in the longitudinal direction, an elasticity under compression limit of at least 645 MPa and an elongation of at least 7%.