A steel sheet for a drawn can has a predetermined chemical composition and has a ferrite single-phase structure with a crystal grain size number of 11.0 or more, the sheet thickness is 0.15 to 0.50 mm, in an L direction of the steel sheet after an ageing treatment at 100 C. for one hour, an yield strength YP is 220 to 290 MPa, a tensile strength TS is 330 to 390 MPa, a total elongation EL is 32% or more, an yield point elongation YP-EL is 0%, an average plastic strain ratio r.sub.m is more than 1.35, and an in-plane anisotropy r is 0.30 to +0.15.

A method of pretinning a guidewire core made of shape memory alloy and having an elongate axis, comprising: placing a ball of solder in a pocket in a soldering block; melting the ball of solder; holding a guidewire core over the ball of solder; lowering the guidewire core into the ball of solder; removing the guidewire from the ball of solder.

A method of pretinning a guidewire core made of shape memory alloy and having an elongate axis, comprising: placing a ball of solder in a pocket in a soldering block; melting the ball of solder; holding a guidewire core over the ball of solder; lowering the guidewire core into the ball of solder; removing the guidewire from the ball of solder.

A Sn-plated steel sheet according to the present invention includes a steel sheet, a Sn-plated layer that is provided on at least one surface of the steel sheet, and a film that is provided on a surface of the Sn-plated layer and includes zirconium oxide and tin oxide, in which an amount of the zirconium oxide in the film is 0.2 mg/m.sup.2 to 50 mg/m.sup.2 in terms of metal Zr amount, in a depth direction analysis by X-ray photoelectron spectroscopy, a depth position A at which an element concentration of Zr present as the zirconium oxide is maximum is positioned closer to a surface of the film than a depth position B at which an element concentration of Sn present as the tin oxide is maximum, and a distance between the depth position A and the depth position B in a depth direction is 0.5 nm or more.

A Sn-plated steel sheet according to the present invention includes a steel sheet, a Sn-plated layer that is provided on at least one surface of the steel sheet, and a film that is provided on a surface of the Sn-plated layer and includes zirconium oxide and tin oxide, in which an amount of the zirconium oxide in the film is 0.2 mg/m.sup.2 to 50 mg/m.sup.2 in terms of metal Zr amount, in a depth direction analysis by X-ray photoelectron spectroscopy, a depth position A at which an element concentration of Zr present as the zirconium oxide is maximum is positioned closer to a surface of the film than a depth position B at which an element concentration of Sn present as the tin oxide is maximum, and a distance between the depth position A and the depth position B in a depth direction is 0.5 nm or more.

A core material has a core 12; a solder layer 16 made of a (SnBi)-based solder alloy provided on an outer side of the core 12; and a Sn layer 20 provided on an outer side of the solder layer 16. The core contains metal or a resin. When a concentration ratio of Bi contained in the solder layer 16 is a concentration ratio (%)=a measured value of Bi (% by mass)/a target Bi content (% by mass), or a concentration ratio (%)=an average value of measured values of Bi (% by mass)/a target Bi content (% by mass), the concentration ratio is 91.4% to 106.7%. The thickness of the Sn layer 20 is 0.215% or more and 36% or less of the thickness of the solder layer 16.

The present disclosure provides a copper-phosphorus-tin brazing wire and a preparation method thereof, relates to the technical field of brazing materials. The copper-phosphorus-tin brazing wire is of a three-layer structure, the inner layer is Cu, the middle layer is Cu-14P alloy, and the outer layer is Sn, wherein the mass percentage of Sn is over 7%. The present disclosure solves the technical problems in the prior art that the copper-phosphorus-silver brazing filler metal is prone to produce defects such as pores and inclusions when brazing copper alloys, which leads to the decline of the mechanical properties of the joint, and simultaneously provides the preparation method of the copper-phosphorus-tin brazing wire, such that the technical problem that it is difficult to obtain copper-phosphorus-tin brazing wire with a wire diameter below 0.5 mm under the condition of high Sn content is solved.

The present disclosure provides a copper-phosphorus-tin brazing wire and a preparation method thereof, relates to the technical field of brazing materials. The copper-phosphorus-tin brazing wire is of a three-layer structure, the inner layer is Cu, the middle layer is Cu-14P alloy, and the outer layer is Sn, wherein the mass percentage of Sn is over 7%. The present disclosure solves the technical problems in the prior art that the copper-phosphorus-silver brazing filler metal is prone to produce defects such as pores and inclusions when brazing copper alloys, which leads to the decline of the mechanical properties of the joint, and simultaneously provides the preparation method of the copper-phosphorus-tin brazing wire, such that the technical problem that it is difficult to obtain copper-phosphorus-tin brazing wire with a wire diameter below 0.5 mm under the condition of high Sn content is solved.

It is provided a surface-treated steel sheet that can be produced without using hexavalent chromium and has excellent sulfide staining resistance and coating secondary adhesion. It is a surface-treated steel sheet having: a Sn plating layer; a metallic Cr layer disposed on the Sn plating layer; and a Cr oxide layer disposed on the metallic Cr layer, on at least one surface of a steel sheet, and the surface-treated steel sheet has a water contact angle of 50? or less and a total atomic ratio of K, Na, Mg, and Ca adsorbed on the surface to Cr of 5% or less.

It is provided a surface-treated steel sheet that can be produced without using hexavalent chromium and has excellent sulfide staining resistance and coating secondary adhesion. It is a surface-treated steel sheet having: a Sn plating layer; a metallic Cr layer disposed on the Sn plating layer; and a Cr oxide layer disposed on the metallic Cr layer, on at least one surface of a steel sheet, and the surface-treated steel sheet has a water contact angle of 50? or less and a total atomic ratio of K, Na, Mg, and Ca adsorbed on the surface to Cr of 5% or less.