A welding method for obtaining a lap fillet welded joint excellent in tensile strength, without causing an increase in welding deformation, not fracturing at the weld metal when a tensile load is applied, that is, a method of overlaying at least scheduled welding locations of a first steel sheet with a tensile strength of 780 MPa or more and a second steel sheet and fillet welding an end part of the first steel sheet and a surface of the second steel sheet, characterized by providing a reinforcing part at a surface of the first steel sheet at the opposite side to the surface to be overlaid with the second steel sheet and fillet welding one end part of the reinforcing material and the surface of the first steel sheet and by fillet welding the end part of the reinforcing part, the end part of the first steel sheet, and the surface of the second steel sheet so as to be covered by the weld metal.

The present invention relates to an automatic welding system for a corrugated membrane sheet of a membrane type liquefied-gas cargo hold, a structure for guiding and fixing an automatic welding apparatus for a corrugated membrane sheet of a membrane type liquefied-gas cargo hold, and a structure for guiding an automatic welding apparatus for a corrugated membrane sheet of a membrane type liquefied-gas cargo hold. When a corrugated membrane sheet is welded, a cross-anchor strip having a fixing groove is installed on a portion where longitudinal and lateral anchor strips, which are attached to the upper surface of a heat insulating panel on which the corrugated membrane sheet is mounted, cross each other, which makes it possible to install a welding guide that supports the automatic welding apparatus and guides movement of the automatic welding apparatus using the fixing groove, thereby stably performing automatic welding on the corrugated membrane sheet.

The present invention relates to an automatic welding system for a corrugated membrane sheet of a membrane type liquefied-gas cargo hold, a structure for guiding and fixing an automatic welding apparatus for a corrugated membrane sheet of a membrane type liquefied-gas cargo hold, and a structure for guiding an automatic welding apparatus for a corrugated membrane sheet of a membrane type liquefied-gas cargo hold. When a corrugated membrane sheet is welded, a cross-anchor strip having a fixing groove is installed on a portion where longitudinal and lateral anchor strips, which are attached to the upper surface of a heat insulating panel on which the corrugated membrane sheet is mounted, cross each other, which makes it possible to install a welding guide that supports the automatic welding apparatus and guides movement of the automatic welding apparatus using the fixing groove, thereby stably performing automatic welding on the corrugated membrane sheet.

A process is disclosed for laser-welding sheet metal plates that have an aluminum-silicon containing pre-coat layer. The pre-coated sheet metal plates are arranged one relative to another such that an edge of one of the plates is adjacent to and in contact with an edge of the other one of the plates, and a laser-welded joint is formed along the adjacent edges of the pre-coated plates. In particular the joint is formed absent removing the aluminum-silicon containing layer from along the adjacent edges, such that aluminum from the aluminum-silicon containing layer enters into the melt pool that is formed. Additionally, an alloying material is introduced into the melt pool during forming the laser-welded joint and forms a compound with at least some of the aluminum in the melt pool.

A system and method is provided in which a welding system modulates the heat input into a weld joint during welding by changing between a high heat input welding waveform and a low heat input welding waveform. The system can utilize detected weld joint geometry and thickness to vary the utilization of the high heat and low heat waveform portions to change the weld bead profile during welding. Additionally, the wire feed speed is changed with the changes between the high heat input and low heat input portions of the welding waveform.

A system and method is provided in which a welding system modulates the heat input into a weld joint during welding by changing between a high heat input welding waveform and a low heat input welding waveform. The system can utilize detected weld joint geometry and thickness to vary the utilization of the high heat and low heat waveform portions to change the weld bead profile during welding. Additionally, the wire feed speed is changed with the changes between the high heat input and low heat input portions of the welding waveform.

Structure including joint structure of dissimilar materials comprises a roof panel and a skeletal body. The roof panel has a bent portion at its end and is a panel member made of an aluminum alloy. The skeletal body has a support portion for supporting the first member and is made of steel. The roof panel and the skeletal body are joined by continuous welding of a vicinity of an apex of the bent portion of the roof panel and the support portion of the skeletal body, a reinforcing plate is joined to the roof panel at least partially along the joining portion with the skeletal body.

Stiffening beads (55A, 55B) are formed in turned portions in a region of a fillet bead (53) formed in a single stroke manner. At this time, it is set in such a manner that welding start positions of the stiffening beads (55A, 55B) are in a region near the fillet bead and do not exist independently without mixing with other weld beads.

Stiffening beads (55A, 55B) are formed in turned portions in a region of a fillet bead (53) formed in a single stroke manner. At this time, it is set in such a manner that welding start positions of the stiffening beads (55A, 55B) are in a region near the fillet bead and do not exist independently without mixing with other weld beads.

A fillet arc welded joint formed by fillet arc welding at least two metal members, comprising a remelted and solidified portion obtained by irradiating a laser at a weld toe portion of the fillet arc welding of at least one metal member and a region including a boundary of the heat affected zone caused by the fillet arc welding at the surface of that metal member, the remelted and solidified portion being a range from a surface of the metal member to a depth of or less of the thickness of that metal member, an average effective crystal grain diameter of prior austenite at a heat affected zone from a boundary of the remelted and solidified portion at the surface of the metal member to a depth of 0.1 mm in the thickness direction of the metal member being 20 m or less.