A sandwich structure forming method including the steps of (1) providing a sandwich structure comprising a core positioned between a first liner sheet and a second liner sheet; (2) positioning the sandwich structure into a cavity of a die assembly; and (3) pressurizing the core to expand the sandwich structure into engagement with the die assembly.

A method for producing an alloy steel composition includes the following steps: performing a first heat treatment on an alloy steel composition and maintaining for a first time period to soften the alloy steel composition; performing a first cooling treatment on the softened alloy steel composition; performing a treatment on the softened the alloy steel composition to form a workpiece; performing a second heat treatment on the workpiece and maintaining for a second time period; and performing a second cooling treatment on the workpiece to make the workpiece become to be a Bainite structure, and a cooling rate of the second cooling treatment is high than the cooling rate of the first cooling treatment.

Disclosed are a ferritic stainless steel capable of inhibiting high temperature oxidation through generation of an effective oxide scale, and manufacturing method thereof. The ferritic stainless steel excellent in oxidation resistance at high temperature according to an embodiment of the present disclosure includes, in percent (%) by weight of the entire composition, Cr: 10 to 30%, Si: 0.2 to 1.0%, Mn: 0.1 to 2.0%, W: 0.3 to 2.5%, Ti: 0.001 to 0.15%, Al: 0.001 to 0.1%, the remainder of iron (Fe) and other inevitable impurities, and satisfies a following equation (1).

W/(Ti+Al)10(1)

An alloy composition is provided. The alloy composition includes chromium (Cr) at a concentration of greater than or equal to about 0.5 wt. % to less than or equal to about 9 wt. %, carbon (C) at a concentration of greater than or equal to about 0.15 wt. % to less than or equal to about 0.5 wt. %, manganese (Mn) at a concentration of greater than or equal to about 0 wt. % to less than or equal to about 3 wt. %, silicon (Si) at a concentration of greater than or equal to about 0.5 wt. % to less than or equal to about 2 wt. %, and a balance of the alloy composition being iron. Methods of making shaped steel objects from the alloy composition are also provided.

The present disclosure provides a wire rod for cold heading that can shorten the spheroidizing heat treatment time, processed products using the same, and manufacturing method thereof. A wire rod for cold heading according to an embodiment of present disclosure includes, in percent (%) by weight of the entire composition, C: 0.15 to 0.5%, Si: 0.1 to 0.4%, Mn: 0.3 to 1.5%, Cr: 0.1 to 1.5%, Al: 0.02 to 0.05%, N: 0.004 to 0.02%, at least one selected from the group consisting of Nb: 0.001 to 0.03%, V: 0.01 to 0.3%, Mo: 0.01 to 0.5%, Ti: 0.001 to 0.03%, and the remainder of iron (Fe) and other inevitable impurities, and the microstructure has a long and short axis ratio of cementite present in pearlite colonies of 200:1 or less.

A bolt of the present invention is a high-strength bolt of high-carbon steel having a tempered martensite structure, wherein the composition of the bolt comprises: 0.50 mass % or more and 0.65 mass % or less of carbon (C); 1.5 mass % or more and 2.5 mass % or less of silicon (Si); 1.0 mass % or more and 2.0 mass % or less of chromium (Cr); 0.2 mass % or more and 1.0 mass % or less of manganese (Mn); and 1.5 mass % or more and 5.0 mass % or less of molybdenum (Mo); a total content of impurities being phosphor (P) and sulfur (S) is 0.03 mass % or more; and the remaining is iron (Fe). Furthermore, the carbon concentration satisfies the following Formula (1): 0.75X<1 . . . Formula (1) wherein, in Formula (1), X represents surface carbon concentration/inner carbon concentration. Therefore, the bolt of the present invention has low quench cracking susceptibility and excellent delayed fracture resistance, because an increase in temperature at which martensite transformation occurs (Ms point) on the surface side is held down.

A vacuum heat treatment apparatus capable of charging or withdrawing an object into or from either a heating chamber or a cooling chamber by a transport means. The vacuum heat treatment apparatus includes: A vacuum heat treatment apparatus, including: a plurality of heating chambers charged with an object and subjected to a heat treatment process; a rail disposed between the plurality of heating chambers; a bogie moving while being disposed on the rail; a cooling chamber disposed on the bogie and cooling the object; and a transport means disposed on the bogie and provided to charge or withdraw the object into or from any one of the plurality of heating chambers and the cooling chamber.

An additive layer manufactured hot work tool according to the present disclosure includes a component composition of by mass %, C: 0.3-0.5% to Si: 2.0% or less, Mn: 1.5% or less, P: 0.05% or less, S: 0.05% or less, Cr: 3.0 to 6.0%, 1 or 2 kinds of compounds of Mo and W, a relation between Mo and W being represented by a relational expression of (Mo+1/2W): 0.5 to 3.5%, V: 0.1 to 1.5%, Ni: 0 to 1.0%, Co: 0 to 1.0%, and Nb: 0 to 0.3%, and with Fe and an unavoidable impurity as a remainder, and an area ratio of defects having an area of 1 m.sup.2 or more is 0.6% or less in a cross section parallel to the amination direction.

A tool for simultaneous local stress relief of each of a multiple of linear friction welds includes a columnar track defined along an axis, the columnar track having a helical slot; and a support structure engaged with the helical slot to translate and rotate a heat treat fixture portion along the axis.

A system for manufacturing a part is provided. The system includes a gantry, a first mobile arm and a second mobile arm, at least one conveyor and at least one sensor. The gantry has a first member and a second member disposed opposite the first member so as to define an opening. The first and the second mobile arms are disposed on the first and the second members, respectively. The at least one conveyor is operative to move the part through the opening so as to position the part within access of the first and the second mobile arms. The at least one sensor is operative to guide the first and the second mobile arms to one or more areas of the part. The first and the second mobile arms are operative to perform a manufacturing process on the part at the one or more areas.