Some embodiments of the present disclosure provide manufacturing methods for a wheel rim, a spoke and a steel wheel and a steel wheel formed by the methods. The methods includes that: a wheel rim/a spoke blank is heated in a heating furnace, and the heated wheel rim/the heated spoke blank is transferred onto a hot press. A temperature of the wheel rim/the spoke blank being required to be kept above a required temperature in a process of transferring the heated wheel rim/the heated spoke blank to the hot press. Then the wheel rim/the spoke blank is formed in the hot press. A formed wheel rim and a formed spoke are connected to product a steel wheel.

A method of producing a hot press-formed product, in which a die includes a hard layer having a skewness (Rsk), as measured in a direction from the outside of a die hole toward an inside of the die hole, of from −5.0 to 1.2, and a hardness Hv_Die of from HV 1,000 to 1,800, over the entirety of a region of a steel sheet contact surface that is adjacent to a die shoulder portion. The steel sheet contact surface is a surface located outside of the die hole and configured to contact a hot-dip galvannealed steel sheet that is to be subjected to hot press forming.

A zinc-plated steel sheet for hot stamping according to an aspect of the present invention includes a base steel sheet satisfying a predetermined composition of chemical components, wherein an amount of solid-soluted B is 10 ppm or more and the base steel sheet has a hot-dip galvannealed layer or a hot dip galvanized layer on at least one face thereof.

A hot stamped body comprising a steel base material and an Al—Zn—Mg-based plating layer formed on a surface of the steel base material, wherein the plating layer has a predetermined chemical composition, the plating layer comprises an interfacial layer positioned at an interface with the steel base material and containing Fe and Al and a main layer positioned on the interfacial layer, the main layer comprises, by area ratio, 10.0 to 70.0% of an Mg—Zn containing phase and 30.0 to 90.0% of an Fe—Al containing phase, the Mg—Zn containing phase comprises at least one selected from the group consisting of an MgZn phase, Mg.sub.2Zn.sub.3 phase, and MgZn.sub.2 phase, and the Fe—Al containing phase comprises an FeAl phase and Fe—Al—Zn phase and an area ratio of the Fe—Al—Zn phase in the main layer is more than 10.0 to 75.0%.

A manufacturing method of a plate member, in which a strip material can be positioned with respect to a die all through stamping operations using a pilot hole formed in an initial phase of the stamping operations. The plate member is manufactured by a press machine in which a progressive stamping die having a plurality of stations is placed. The manufacturing method comprises: forming an oval pilot hole 14 in an uncoiled strip 13; and stamping the uncoiled strip 13 by a plurality of operations while bringing a pilot pin 17 into contact with an inner edge of the pilot hole 14 at the operation before the pilot hole 14 is displaced, and at the operation after the pilot hole 14 is displaced.

A manufacturing method of a plate member, in which a strip material can be positioned with respect to a die all through stamping operations using a pilot hole formed in an initial phase of the stamping operations. The plate member is manufactured by a press machine in which a progressive stamping die having a plurality of stations is placed. The manufacturing method comprises: forming an oval pilot hole 14 in an uncoiled strip 13; and stamping the uncoiled strip 13 by a plurality of operations while bringing a pilot pin 17 into contact with an inner edge of the pilot hole 14 at the operation before the pilot hole 14 is displaced, and at the operation after the pilot hole 14 is displaced.

A stamping part design method including obtaining a first B-rep model having a 3D boundary curve formed by boundary-curve edges and obtaining a first and second value representing a g1-continuity and a g2-continuity extrapolation length requirement. The method includes determining a second B-Rep model comprising an extrapolation of the first B-Rep model and presenting at least a g2-continuity over a length of the extrapolation patches equal to the second value and then at least a g1-continuity over a length of the extrapolation patches equal to the first value. The determination of the second B-Rep model includes partitioning the boundary-curve edges into first groups of consecutive first boundary-curve edges, and second groups of consecutive second boundary-curve edges and applying a surface-extension operator to each first group and filling the gaps. This forms an improved solution of stamping part design.

A die includes a die body and a removable shell. The die body includes a supply flow channel formed inside the die body. One end of the supply flow channel opens at the surface of the die body. The supply flow channel is to be supplied with a fluid for temperature adjustment. The removable shell is mounted removably to the surface of the die body. The removable shell includes an outer surface that constitutes at least a part of the forming surface of the die. A temperature adjustment space is provided in the surface of the die body or in the removable shell. The temperature adjustment space is in communication with the supply flow channel. The removable shell is divided into a plurality of shell pieces. The plurality of shell pieces are arranged in a direction intersecting the longitudinal direction of the die on the surface of the die body.

Steel sheet coating compositions in which polymeric resin or ceramic properties are produced by admixing an aluminum coordinate complex and an aluminum resin, a polysilazane as a source of silicon, an organic solvent, an organic synthesis catalyst, and optionally a non-metallic, non-ionic, low-nucleophilic base. The admixed coating is applied to sheet steel prior to hot-stamping in order to inhibit surface formation of iron oxides and to improve steel sheet surface characteristics.

Steel sheet coating compositions in which polymeric resin or ceramic properties are produced by admixing an aluminum coordinate complex and an aluminum resin, a polysilazane as a source of silicon, an organic solvent, an organic synthesis catalyst, and optionally a non-metallic, non-ionic, low-nucleophilic base. The admixed coating is applied to sheet steel prior to hot-stamping in order to inhibit surface formation of iron oxides and to improve steel sheet surface characteristics.