Nisshin Steel Co., Ltd.

Nippon Steel Nisshin Co., Ltd.

Kazuaki Hosomi

Takefumi Nakako

Kouki Tomimura

Susumu Fujiwara

Hiroshi Asada

Tomokazu Nobutoki

Minoru Saito

Yukio Katagiri

Keiji Yamamoto

Kentaro Hirata

Masaaki Uranaka

Kenji Ogawa

Toshiharu Kitsutaka

A welded member includes a hot dip Zn-based alloy coated steel sheet as a base material and has excellent corrosion resistance and weld bead shear strength. In the welded member in which a lower sheet and an upper sheet, which are hot dip Zn-based alloy coated steel sheets, are stacked and arc-welded together, a weld bead is formed so that a cross-sectional width W satisfies the following formula 2T&#x2264;W&#x2264;6T, and a blowhole occupancy Br represented by the following formula becomes not more than 50%: Br=(&#x3a3;di/L)&#xd7;100, where T represents a thickness of the hot dip Zn-based alloy coated steel sheet, di represents a length of an i-th blowhole observed in X-ray radiography, and L represents a length of the weld bead.

Welded member and method for manufacturing same

Hot dip Zn-based alloy coated steel sheets (') are arc-weld in such a way that (a) a current waveform is a pulsed current waveform in which (i) a peak current and a base current alternate with each other at a pulse period of 1 ms to 50 ms and (ii) an average welding current is 100 A to 350 A and (b) an average welding voltage is 20 V to 35 V. Each of the hot dip Zn-based alloy coated steel sheets (&#x2032;) includes a coating layer that contains Zn as a main component and that contains Al at a concentration of 1.0% by mass to 22.0% by mass, and has a coating weight W of 15 g/mto 250 g/m.

Arc welding method for hot-dip galvanized steel plate having excellent appearance of welded part and high welding strength, method for manufacturing welding member, and welding member

The present invention provides a method for MIG brazing an Al alloy to a steel sheet so as to manufacture a lap joint member that excels in bonding strength with respect to the Al alloy. With the MIG brazing method, a bonding target sheet, specifically, an Al sheet or an Al alloy sheet is bonded to a hot dip Zn-based alloy coated steel sheet () whose coating layer contains Al in an amount of 1.0% by mass to 22.0% by mass. A target location of MIG brazing is a region between (i) an intersection (C) of one end of an end surface () of the bonding target sheet and the hot dip Zn-based alloy coated steel sheet and (ii) the other end (U) of the end surface of the bonding target sheet.

Method for MIG brazing, method for manufacturing lap joint member, and lap joint member

The present invention provides a method for laser brazing an Al alloy to a steel sheet so as to produce a lap joint member that excels in bonding strength with respect to the Al alloy. The laser brazing method includes a brazing step of forming a brazed part () for bonding an Al alloy () to a hot dip Zn-based alloy coated steel sheet () in which a coating layer () contains 1.0 to 22.0% by mass of Al and a coating weight per surface is 15 to 250 g/m.

Laser brazing method and production method for lap joint member

Provided are: an arc welding method that suppresses occurrences of blow holes in initial parts and final parts in a Zn plated steel sheet and reduces the occupancy ratio for blow holes in the welded part as a whole; and a welded joint.

Arc welding method for Zn plated steel sheet and arc welded joint

A laser welding method for welding materials having different thicknesses includes abutting two plates having different thicknesses such that one surface of the thin plate and one surface the thick plate are made flush with each other; and thereafter welding the plates by applying a laser beam to abutting surfaces thereof, wherein the laser beam is directed obliquely relative to an abutting end face of the thick plate, a target position of the laser beam is determined on the abutting end face of the thick plate, and a target position depth D on the abutting end face of the thick plate is determined based on the formula t/3&#x2264;D&#x2264;t where t is a thickness of the abutting end face of the thin plate.

Method for laser welding of materials having different thicknesses

[Problem] To provide a steel sheet hot-dip-plated with a Zn&#x2014;Al&#x2014;Mg-based alloy coating, which is remarkably improved in point of all the burring workability, the liquid metal embrittlement cracking resistance and the corrosion resistance in the welded part thereof, as a steel material favorable for arc-welded structural members. [Means for Resolution] A plated steel sheet having a Zn&#x2014;Al&#x2014;Mg-based alloy coating layer formed by hot-dipping on the surface of a base steel sheet for welded structural members, wherein the base steel sheet has a specific chemical composition and has a metallographic structure of such that Ti-containing precipitates having a mean particle diameter of at most 20 nm are dispersed in the matrix formed of a ferrite phase therein, and wherein the liquid metal embrittlement cracking sensitivity index H3 value of the base steel sheet represented by the following formula (3) and indicating the relationship between the contents of the steel components and the thickness t (mm) of the steel sheet is at most 2.90:H3 Value=C/0.2+Si/5.0+Mn/1.3+Cr/1.0+Mo/1.2+0.4&#x2212;0.7(Cr+Mo)&#x2003;&#x2003;(3)

Zn&#x2014;Al&#x2014;Mg based alloy hot-dip plated steel sheet, and method for producing the same

The surface of a stainless steel sheet before Fe-coating and the surface of the same stainless steel sheet after Fe-coating are analyzed by X-ray fluorescent analysis to determine the ratio of a fluorescent X-ray intensity I.sub.Cr b ascribable to CF to a fluorescent X-ray intensity I.sub.Fe b ascribable to Fe before Fe-coating, I.sub.Cr b/I.sub.Fe b, and the ratio of a fluorescent X-ray intensity I.sub.Cr a ascribable to Cr to a fluorescent X-ray intensity I.sub.Fe a ascribable to Fe after Fe-coating, I.sub.Cr a/I.sub.Fe a, and the resulting values are substituted in the following equation to calculate an Fe coating weight W (g/m.sup.2).

Growing community of inventors

Tokyo, Japan

Kazuaki Hosomi