Disclosed is a stainless steel having excellent surface electrical conductivity for a fuel cell separator. According to an embodiment of the disclosed stainless steel having excellent surface electrical conductivity for a fuel cell separator, a value of the following surface oxide atomic ratio (1) may be 0.5 or less, as measured on the surface of a stainless steel containing 15 wt % or more of Cr by X-ray angle-resolved photoemission spectroscopy using an Al-Kα X-ray source under the condition where a take-off angle of photoelectrons is from 12° to 85°.

[00001]$\begin{array}{cc}\frac{\begin{array}{c}\mathrm{sum}\mathrm{of}\mathrm{atomic}\mathrm{concentrations}\left(\mathrm{at}\%\right)\\ \mathrm{of}\mathrm{metal}\mathrm{elements}\mathrm{in}\mathrm{metal}\mathrm{oxide}\left(\mathrm{MO}\right)\end{array}}{\begin{array}{c}\mathrm{sum}\mathrm{of}\mathrm{atomic}\mathrm{concentrations}\left(\mathrm{at}\%\right)\\ \mathrm{of}\mathrm{metal}\mathrm{elements}\mathrm{in}\mathrm{total}\mathrm{oxides}\mathrm{and}\mathrm{hydroxides}\end{array}}& \left(1\right)\end{array}$

The metal oxide (MO) includes a mixed oxide: M represents an alloying element other than Cr and Fe or a combination thereof in the matrix; and O represents oxygen. The total oxides and hydroxides include a Cr oxide, a Cr hydroxide, an Fe oxide, an Fe hydroxide, and the metal oxide (MO).

A novel method of blackening surgical needles is disclosed. Surgical needles having outer surfaces are first placed into a first pretreatment bath having a novel composition. The needles are then placed into a second blackening bath having a novel composition for a sufficient period of time to effectively blacken the surfaces of the needles. The novel methods for blackening the surfaces of a stainless steel alloy surgical needle provide a chromium (VI)-free alternative to current needle manufacturing processes. Another unique feature of this novel method is its short processing time. The blackening processes of the present invention can be utilized for in-line treatment processes which can be easily incorporated into high speed needle manufacturing processes, such as strip mounted processes. In addition, the processes of the present invention are readily adaptable to batch processes. Also disclosed are novel systems for blackening surgical needles and novel blackening baths for surgical needles.

This austenitic stainless steel contains, in terms of % by mass: C: 0.100% or less, Si: 3.00% or less, Mn: 0.01% or more and 5.00% or less, P: 0.100% or less, S: 0.0050% or less, Ni: 7.00% or more and 38.00% or less, Cr: 17.00% or more and 28.00% or less, Mo: 10.00% or less, and N: more than 0.100% and 0.400% or less, with a remainder being Fe and impurities, and a brightness difference ΔL of a surface of a stainless steel is 5 or less.

Disclosed is a stainless steel having excellent surface electrical conductivity for a fuel cell separator. According to an embodiment of the disclosed stainless steel having excellent surface electrical conductivity for a fuel cell separator, a value of the following surface oxide atomic ratio (1) may be 0.08 or more, as measured on the surface of a stainless steel containing 15 wt % or more of Cr by X-ray angle-resolved photoemission spectroscopy using an Al-Kα X-ray source under the condition where a take-off angle of photoelectrons is from 12° to 85°.

[00001]$\begin{array}{cc}\frac{\mathrm{sum}\mathrm{of}\mathrm{atomic}\mathrm{concentrations}\left(\mathrm{at}\%\right)\mathrm{of}\mathrm{Cr}\mathrm{in}\mathrm{Cr}\mathrm{hydroxide}}{\begin{array}{c}\mathrm{sum}\mathrm{of}\mathrm{atomic}\mathrm{concentrations}\left(\mathrm{at}\%\right)\mathrm{of}\mathrm{metal}\mathrm{elements}\\ \mathrm{in}\mathrm{total}\mathrm{oxides}\mathrm{and}\mathrm{hydroxides}\end{array}}& \left(1\right)\end{array}$

The Cr hydroxide represents CrOOH, Cr(OH).sub.2, or Cr(OH).sub.3. The total oxides and hydroxides include a Cr oxide, the Cr hydroxide, an Fe oxide, an Fe hydroxide, and a metal oxide (MO), and the metal oxide (MO) includes a mixed oxide, wherein M represents an alloying element other than Cr and Fe or a combination thereof in a matrix, and O represents oxygen.

A hot-rolled steel sheet for a non-oriented electrical steel sheet according to one aspect of the present invention contains, by mass %, C: 0.0050% or less, Si: 0.5% or more and 3.5% or less, Mn: 0.1% or more and 1.5% or less, Al: 0.1% or more and 1.5% or less, Cu: 0.01% or more and 0.10% or less, Sn: 0.01% or more and 0.20% or less, and a remainder including Fe and impurities, in which the hot-rolled steel sheet has a Cu concentration peak value of 0.12% or more in a range from a surface thereof to a depth of 10 μm.

The present invention has as its object the provision of a coated steel member and coated steel sheet excellent in hydrogen embrittlement resistance in a corrosive environment and methods for manufacturing the same. The coated steel member of the present invention is provided on its surface with an Al—Fe-based coating containing Cu and one or more of Mo, Ni, Mn, and Cr in a total by mass % of 0.12% or more by heating, cooling, and manufacturing a coated steel sheet having a layer containing Cu on its surface under predetermined conditions.

A novel method of blackening surgical needles is disclosed. Surgical needles having outer surfaces are first placed into a first pretreatment bath having a novel composition. The needles are then placed into a second blackening bath having a novel composition for a sufficient period of time to effectively blacken the surfaces of the needles. The novel methods for blackening the surfaces of a stainless steel alloy surgical needle provide a chromium (VI)-free alternative to current needle manufacturing processes. Another unique feature of this novel method is its short processing time. The blackening processes of the present invention can be utilized for in-line treatment processes which can be easily incorporated into high speed needle manufacturing processes, such as strip mounted processes. In addition, the processes of the present invention are readily adaptable to batch processes. Also disclosed are novel systems for blackening surgical needles and novel blackening baths for surgical needles.

A cold-rolled steel sheet has excellent chemical convertibility and excellent corrosion resistance after coating. A method of manufacturing a cold-rolled steel sheet includes first pickling applied to a steel sheet which is continuously annealed after cold rolling, second pickling applied to the steel sheet subsequently and, thereafter, neutralizing treatment applied to the steel sheet using an alkaline solution.

A high-carbon steel sheet includes: a chemical composition represented by, in mass %, C: 0.30% to 0.70%, B: 0.0004% to 0.0035%, and others; and a structure represented by a spheroidized ratio of cementite: 80% or more; and an average diameter of cementite: 0.3 μm to 2.2 μm, wherein a coefficient of micro-friction of ferrite on a surface of the steel sheet is less than 0.5.

Ferritic stainless steel is characterized by including, by mass %: Cr: 12.0% to 16.0%; C: 0.020% or less; Si: 2.50% or less; Mn: 1.00% or less; P: 0.050% or less; S: 0.0030% or less; Al: 2.50% or less; N: 0.030% or less; Nb: 0.001% to 1.00%; one or more of B: 0.0200% or less, Sn: 0.20% or less, Ga: 0.0200% or less, Mg: 0.0200% or less, and Ca: 0.0100% or less; and a balance consisting of Fe and impurities, in which Expression (1) is satisfied.
10(B+Ga)+Sn+Mg+Ca>0.020  (1)