A panel that is excellent in both appearance and dent resistance after being formed from a starting material is provided. The panel has a steel sheet including martensite, and a surface roughness parameter (Sa) at a flat part of a center-side portion of the panel is Sa≤0.500 μm. In laths of the martensite, the panel has precipitates having a major axis of 0.05 μm to 1.00 μm and an aspect ratio of 3 or more in an amount of 15 precipitates/μm.sup.2 or more. A ratio YS.sub.1/YS.sub.2 between a yield stress YS.sub.1 measured in a tensile test specimen cut out from the flat part of the center-side portion of the panel and a yield stress YS.sub.2 measured in a tensile test specimen cut out from an end part of the panel is 0.90 to 1.10.

Improved steel compositions and methods of making the same are provided. More particularly, the present disclosure provides high manganese (Mn) steel having enhanced strength and/or performance at cryogenic temperatures, and methods for fabricating high manganese steel compositions having enhanced strength and/or performance at cryogenic temperatures. The advantageous steel compositions/components of the present disclosure improve one or more of the following properties: strength, toughness, elastic modulus, thermal expansion coefficient and/or thermal conductivity. In general, the present disclosure provides high manganese steels tailored to resist wear and/or deformation at cryogenic temperatures.

The invention relates to a method for producing a flat steel product made of a medium manganese steel having a TRIP/TWIP effect. The aim of the invention is to achieve an improvement in the yield strength when a sufficient residual deformability of the produced flat steel product is obtained. This aim is achieved by the following steps: cold rolling a hot or cold strip, annealing the cold-rolled hot or cold strip at 500 to 840° C. for 1 minute to 24 hours, temper rolling or finishing the annealed hot or cold strip to form a flat steel product having a degree of deformability between 0.3% and 60%. The invention further relates to a flat steel product produced according to said method and to a use thereof.

Medical instruments, particularly, endodontic instruments with unique limited memory characteristics, and methods for making such instruments. One embodiment includes heat treating a finished endodontic instrument. A related embodiment includes electropolishing a finished endodontic instrument and then heat treating the endodontic instrument.

A steel product includes the following chemical composition in wt. %: C: 0.01 to <0.3, Mn: 4 to <10, Al: 0.003 to 2.9, Mo: 0.01 to 0.8, Si: 0.02 to 0.8, Ni: 0.005 to 3, P: <0.04, S: <0.02, N: <0.02, with the remainder being iron including unavoidable steel-associated elements, wherein an alloy composition satisfies the equation 6<1.5 Mn+Ni<8; or the equation 0.11<C+Al<3, or an alloy composition contains, in addition to Ni, at least one or more of the elements, in wt. %, B: 0.0005 to 0.014; V: 0.006 to 0.1; Nb: 0.003 to 0.1; Co: 0.003 to 3; W: 0.03 to 2 or Zr: 0.03 to 1. The steel product has a microstructure of 2 to 90 vol. % austenite, less than 40 vol. % ferrite and/or bainite, with the remainder being martensite.

The invention relates to a method for manufacturing a ferritic-austenitic stainless steel having good formability and high elongation. The stainless steel is heat treated so that the microstructure of the stainless steel contains 45-75% austenite in the heat treated condition, the remaining microstructure being ferrite, and the measured M.sub.d30 temperature of the stainless steel is adjusted between 0 and 50° C. in order to utilize the transformation induced plasticity (TRIP) for improving the formability of the stainless steel.

A method for the manufacture of a cold rolled, recovered TWIP steel sheet coated with a metallic coating is provided including the following steps: (A) the feeding of a slab having the following composition: 0.1<C<1.2%, 13.0≤Mn<25.0%, S≤0.030%, P≤0.080%, N≤0.1%, Si≤3.0%, and on a purely optional basis, one or more elements such as Nb≤0.5%, B≤0.005%, Cr≤1.0%, Mo≤0.40%, Ni≤1.0%, Cu≤5.0%, Ti≤0.5%, V≤2.5%, Al≤4.0%, 0.06≤Sn≤0.2%, the remainder of the composition making up of iron and inevitable impurities resulting from elaboration; (B) Reheating such slab and hot rolling it; (C) A coiling step; (D) A first cold-rolling; (E) A recrystallization annealing; (F) A second cold-rolling; and (G) A recovery heat treatment performed by hot-dip coating.

A method for the manufacture of a galvannealed steel sheet including the provision of a specific steel sheet, a recrystallization annealing with specific heating, soaking and cooling sub-steps using an inert gas, a hot-dip galvanizing and an alloying treatment; the galvannealed steel sheet and the use of the galvannealed steel sheet.

A method for the manufacture of a galvannealed steel sheet including the provision of a specific steel sheet, a recrystallization annealing with specific heating, soaking and cooling sub-steps using an inert gas, a hot-dip galvanizing and an alloying treatment; the galvannealed steel sheet and the use of the galvannealed steel sheet.

A galvannealed steel sheet ontainabel by a method including the provision of a specific steel sheet, a recrystallization annealing with specific heating, soaking and cooling sub-steps using an inert gas, a hot-dip galvanizing and an alloying treatment.