The present invention discloses a method for ultra-low temperature forming an ultra-thin curved part of a high-strength aluminum alloy. The method includes the following steps: step 1: selecting a cladding with a suitable thickness according to a wrinkle limit of a sheet; step 2: stacking the sheet and the cladding, then putting into a die, and closing a blank holder; step 3: filling a cavity of a female die with an ultra-low temperature medium to cool the sheet to below −160° C.; step 4: applying a set blank holding force by the blank holder, and enabling a male die to go down to form a thin-walled curved part; and step 5: opening the die and taking out the formed thin-walled curved part. The present invention utilizes the favorable formability of the high-strength aluminum alloy at the ultra-low temperature and the instability resistance of the thick sheet.

The present invention discloses a method for ultra-low temperature forming an ultra-thin curved part of a high-strength aluminum alloy. The method includes the following steps: step 1: selecting a cladding with a suitable thickness according to a wrinkle limit of a sheet; step 2: stacking the sheet and the cladding, then putting into a die, and closing a blank holder; step 3: filling a cavity of a female die with an ultra-low temperature medium to cool the sheet to below −160° C.; step 4: applying a set blank holding force by the blank holder, and enabling a male die to go down to form a thin-walled curved part; and step 5: opening the die and taking out the formed thin-walled curved part. The present invention utilizes the favorable formability of the high-strength aluminum alloy at the ultra-low temperature and the instability resistance of the thick sheet.

One embodiment of the present invention provides an Fe-based amorphous alloy ribbon for an Fe-based nanocrystalline alloy, the Fe-based amorphous alloy ribbon being a cooled body of a molten metal that has been applied to a surface of a chill roll, wherein the Fe-based amorphous alloy ribbon includes a recess having a depth of 1 μm or more in a 0.647 mm×0.647 mm region located in a central part, in the ribbon width direction, of a ribbon surface, which is a cooled surface, in which a maximum area of the recess having a depth of 1 μm or more is 3000 μm.sup.2 or less; and a method of manufacturing the same.

One embodiment of the present invention provides an Fe-based amorphous alloy ribbon for an Fe-based nanocrystalline alloy, the Fe-based amorphous alloy ribbon being a cooled body of a molten metal that has been applied to a surface of a chill roll, wherein the Fe-based amorphous alloy ribbon includes a recess having a depth of 1 μm or more in a 0.647 mm×0.647 mm region located in a central part, in the ribbon width direction, of a ribbon surface, which is a cooled surface, in which a maximum area of the recess having a depth of 1 μm or more is 3000 μm.sup.2 or less; and a method of manufacturing the same.

The invention relates to a brake piston 1 for a brake caliper 9 of a disk brake, which is produced using working processes from a metallic material, in particular from a flat metal sheet, and is formed in one piece as a unilaterally open pot with a piston longitudinal axis A, with a piston wall 2 and with a piston head 3. There is a need for robust and light as well as alternatively constructed, efficiently producible and well guided brake pistons. The object is achieved firstly in principle on the basis of a cup-shapedly worked brake piston blank 19, in that at least one locally defined, i.e. partially cold-upset or partially ironed, cylindrical piston wall portion is present with a partially deformed piston wall 2 which is configured in adaptively modified manner by plastic material deformation by means of material redistribution (flow) including strain-hardening of its piston wall thickness of sl−x.

The invention relates to a brake piston 1 for a brake caliper 9 of a disk brake, which is produced using working processes from a metallic material, in particular from a flat metal sheet, and is formed in one piece as a unilaterally open pot with a piston longitudinal axis A, with a piston wall 2 and with a piston head 3. There is a need for robust and light as well as alternatively constructed, efficiently producible and well guided brake pistons. The object is achieved firstly in principle on the basis of a cup-shapedly worked brake piston blank 19, in that at least one locally defined, i.e. partially cold-upset or partially ironed, cylindrical piston wall portion is present with a partially deformed piston wall 2 which is configured in adaptively modified manner by plastic material deformation by means of material redistribution (flow) including strain-hardening of its piston wall thickness of sl−x.

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.

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.

This steel sheet has a predetermined chemical composition, and, on a surface parallel to a surface at a ¼ position of a sheet thickness in a sheet thickness direction from the surface, with respect to a total area of three types of oxides of MnO, Cr.sub.2O.sub.3 and Al.sub.2O.sub.3 having a major axis of more than 1.0 μm, a total area ratio of the MnO and the Cr.sub.2O.sub.3 is 98.0% or more, and an area ratio of the Al.sub.2O.sub.3 is 2.0% or less.

This steel sheet has a predetermined chemical composition, and, on a surface parallel to a surface at a ¼ position of a sheet thickness in a sheet thickness direction from the surface, with respect to a total area of three types of oxides of MnO, Cr.sub.2O.sub.3 and Al.sub.2O.sub.3 having a major axis of more than 1.0 μm, a total area ratio of the MnO and the Cr.sub.2O.sub.3 is 98.0% or more, and an area ratio of the Al.sub.2O.sub.3 is 2.0% or less.