This hot-stamping formed article includes a steel sheet, all or part of the steel sheet has a predetermined chemical composition, at a ¼ depth position of a sheet thickness from a surface of the steel sheet, a microstructure contains, by vol %, more than 90.0% of martensite, the average value of Vickers hardness in a region that is 0.3 mm in a sheet thickness direction and 0.6 mm in a direction orthogonal to the sheet thickness direction is 670 or more, the standard deviation of the Vickers hardness in the region is 20 or less, and the tensile strength is 2300 MPa or more.

These steel sheet for hot stamping and hot-stamping formed body have predetermined chemical composition and metallographic structures, and, in textures of a surface layer region and an inside region, ratios between a pole density of an orientation group consisting of {001}<1-10> to {001}<−1-10> and a pole density of an orientation group consisting of {111}<1-10> to {111}<−1-12> are controlled.

The present disclosure relates to an austenitic stainless alloy comprising in weight % (wt %): C less than 0.03; Si less than 1.0; Mn less than or equal to 1.2; Cr 26.0 to 30.0; Ni 29.0 to 37.0; Mo 6.1 to 7.1 or (Mo+W/2) 6.1 to 7.1; N 0.25 to 0.36; P less than or equal to 0.04; S less than or equal to 0.03; Cu less than or equal to 0.4; balance Fe and unavoidable impurities and to the use thereof and to products made thereof. Thus, the austenitic stainless alloy comprises a low content of manganese in combination with a high content of nitrogen. The present disclosure also relates to the use of said austenitic stainless alloy, especially in highly corrosive environments and to products made of thereof.

The present disclosure relates to an austenitic stainless alloy comprising in weight % (wt %): C less than 0.03; Si less than 1.0; Mn less than or equal to 1.2; Cr 26.0 to 30.0; Ni 29.0 to 37.0; Mo 6.1 to 7.1 or (Mo+W/2) 6.1 to 7.1; N 0.25 to 0.36; P less than or equal to 0.04; S less than or equal to 0.03; Cu less than or equal to 0.4; balance Fe and unavoidable impurities and to the use thereof and to products made thereof. Thus, the austenitic stainless alloy comprises a low content of manganese in combination with a high content of nitrogen. The present disclosure also relates to the use of said austenitic stainless alloy, especially in highly corrosive environments and to products made of thereof.

The present invention provides a microalloyed steel mechanical property prediction method based on globally additive model, including the following steps: determining some influencing factors of the microalloyed steel mechanical property prediction model; calculating the components and contents of carbonitride precipitation in a microalloyed steel rolling process; expressing the microalloyed steel mechanical property prediction model as an additive form of several submodels according to generalized additive model; estimating the microalloyed steel mechanical property prediction model; and verifying reliability of the submodels. The microalloyed steel property prediction models obtained in the foregoing solution have advantages such as high prediction precision and a wide adaptation range, and may be used for design of new products and steel grade component optimization, so as to reduce the quantity of physical tests, shorten the product research and development cycle, and reduce costs.

The production method of a seamless steel pipe includes a heating step of heating an Nb-containing steel material to 800 to 1030° C., a pipe-making step of producing a hollow shell by performing piercing-rolling or elongation-rolling on the Nb-containing steel material, by using a piercing mill including a plurality of skewed rolls, a plug disposed between the plurality of skewed rolls, and a mandrel bar, and a cooling step immediately after rolling, of carrying out cooling using a cooling liquid on a hollow shell portion that passes between rear ends of the plurality of skewed rolls, in the hollow shell, so as to reduce an outer surface temperature of the hollow shell portion to 700 to 1000° C. within 15.0 seconds after the hollow shell portion passes between the rear ends of the plurality of skewed rolls.

Examples of methods of hot forming structural components are provided. The methods include heating a blank made from an Ultra High Strength Steel with an aluminum coating and forming the heated blank in a multi-step apparatus.

A quench and temper steel alloy is disclosed having the following composition in weight percent. TABLE-US-00001 C 0.1-0.4 Mn 0.1-1.0 Si 0.1-1.2 Cr 9.0-12.5 Ni 3.0-4.3 Mo   1-2 Cu 0.1-1.0 Co   1-4 W  0.2 max. V 0.1-0.6 Ti  0.1 max. Nb up to 0.01 Ta up to 0.01 Al   0-0.25 N 0.1-0.35 Ce 0.006 max. La 0.006 max.
The balance of the alloy is iron and the usual impurities found in similar grades of quench and temper steels intended for similar use or service, including not more than about 0.01% phosphorus and not more than about 0.010% sulfur. A quenched and tempered steel article made from this alloy is also disclosed. Further disclosed is a method of making the alloy.

A method for manufacturing a forged component includes: performing hot forging on a material; heating the hot forged material to a first set temperature; and performing warm coining to correctly shape the heated material. The material may be heated to a second set temperature before hot forging. The material heated to the second set temperature may be hot forged. The second set temperature may be higher than the first set temperature. The hot forged material may be subjected to controlled cooling to a third set temperature at a predetermined cooling rate. The controlled cooled material may be heated to the first set temperature. The third set temperature may be lower than or equal to the first set temperature.

A coated metal sheet includes a steel substrate and a coating on at least one surface of the steel substrate. The coating includes between 0.2 and 0.7% by weight of Al, with a remainder of the metal coating being Zn and inevitable impurities. The coated metal sheet was subjected to a skin pass operation after coating. An outer surface of the metal coating has a waviness Wa.sub.0.8 of less than or equal to 0.55 μm.