Proposed is a method of resistance spot welding to join a plurality of overlapping metal sheets, including: dividing a current pattern into two or more steps for welding; before actual welding, performing test welding to store, for each step as a target value, a time variation of an instantaneous amount of heat generated per unit volume and a cumulative amount of heat generated per unit volume; and subsequently, as actual welding, starting welding using, as a standard, a time variation curve of the instantaneous amount of heat generated per unit volume obtained by the test welding, and when a time variation amount of an instantaneous amount of heat generated deviates during any step from the time variation curve by a difference, performing adaptive control welding to control a current passage amount in order to compensate for the difference during a remaining welding time in the step.

Resistance spot welding method

Provided is a ferritic stainless steel excellent in terms of thermal fatigue resistance, high-temperature fatigue resistance and oxidation resistance without adding Mo or W, which is an expensive chemical element and with controlling Nb content to be as small as possible. The chemical composition contains, by mass %, C: 0.020% or less, Si: 3.0% or less, Mn: 3.0% or less, P: 0.040% or less, S: 0.030% or less, Cr: 10% to 25%, N: 0.020% or less, Nb: 0.005% to 0.15%, Al: 0.20% to 3.0%, Ti: 5×(C %+N %) to 0.5%, Mo: 0.1% or less, W: 0.1% or less, Cu: 0.55% to 2.0%, B: 0.0002% to 0.0050%, Ni: 0.05% to 1.0%, and the balance being Fe and inevitable impurities, where C % and N % in the expression 5×(C %+N %) respectively represent the contents (mass %) of the chemical elements C and N.

Ferritic stainless steel

A steel wire for use in the straight polarity carbon dioxide shielded arc welding, which comprises 0.003 to 0.20 mass % of C, 0.05 to 2.5 mass % of Si, 0.25 to 3.5 mass % of Mn, 0.015 to 0.100 mass % of REM (rare earth metals), 0.001 to 0.05 mass % of P, 0.001 to 0.05 mass % of S, and the balanced amount of Fe and inevitable impurities; the steel wire which further comprises 0.0100 mass % or less of O; the steel wire which still further comprises one or more of 0.02 to 0.50 mass % of Ti, 0.02 to 0.50 mass % of Zr and 0.02 to 3.00 mass % of Al; the steel wire which still further comprises 0.0001 to 0.0150 mass % of K; the steel wire which still further comprises 3.0 mass % or less of Cr, 3.0 mass % or less of Ni, 1.5 mass % or lass of Mo, 3.0 mass % or less of Cu, 0.015 mass % or less of B, 0.20 mass % or less of Mg, 0.5 mass % or less of Nb, 0.5 mass % or less of V, 0.020 mass % or less of N; and a welding process which uses one of the above steel wires. The welding process allows the spray transfer of a molten droplet and thus allows the reduction of sputtering and also the formation of a weld bead of an excellent shape, in the carbon dioxide shielded arc welding using a shield gas containing CO2 gas as its main component.

Steel wire for carbon dioxide shielded arc welding and welding process using the same

The invention relates generally to welding and, more specifically, to welding wires for arc welding, such as Gas Metal Arc Welding (GMAW) or Flux Core Arc Welding (FCAW). In one embodiment, a tubular welding wire includes a sheath and a core. Further, the core includes a carbon source and an agglomerate having a Group I or Group II compound, silicon dioxide, and titanium dioxide. Additionally, the carbon source and the agglomerate together comprise less than 10% of the core by weight.

Systems and methods for welding electrodes

The resistance welding method of different kinds of materials is the method for welding an iron material and an aluminum alloy material, and comprises the steps of: performing in advance a coating treatment at least to a portion of the aluminum alloy material, where resistance welding is performed, with any of iron and iron-base alloy and forming a surface layer; and performing resistance welding of the iron material and the aluminum alloy material through the surface layer, and the resistance welding may be any of spot welding and projection welding.

Resistance welding method of different kinds of materials, and resistance welding member of aluminum alloy material and different kind of material

PROBLEM TO BE SOLVED: To provide a welding wire which can maintain a stable feeding performance even in such critical working conditions that the feeding speed of the welding wire increases or the temperature of the welding wire increases as is the case with the gas shielded arc welding under a high heat input and high interpass temperature. SOLUTION: The steel wire material of the welding wire comprises C:0.005-0.09 mass%, Si:0.50-1.2 mass%, Mn:1.50-2.2 mass%, Ti:0.15-0.30 mass%, B:0.0005-0.0035 mass%, Cu:≤0.50 mass%, S:0.005-0.025 mass% and the balance Fe with unavoidable impurities. The surface of the welding wire is covered by a solid lubricant layer of 0.2-1.0 g per the steel wire material of 10 kg, and the surface of the solid lubricant layer is coated with a lubricant of 0.2-1.8 g per the steel wire material of 10 kg. COPYRIGHT: (C)2004,JPO&NCIPI

Steel wire for gas shielded arc welding

A steel wire for MAG welding in DC-electrode negative contains about 0.20% by mass or less of C, about 0.25% to about 2.5% by mass of Si, about 0.45% to about 3.5% by mass of Mn, about 0.005% to about 0.040% by mass of rare-earth elements, about 0.05% by mass or less of P, about 0.05% by mass or less of S, and the balance being Fe and incidental impurities. A method for MAG welding in DC-electrode negative for welding steel sheets having a thickness of about 0.2 to about 4.5 mm using the steel wire is also disclosed.

Steel wire for MAG welding and MAG welding method using the same

PROBLEM TO BE SOLVED: To provide a gas-shielded arc welding method which is suitable for straight polarity d.c. welding, and by which the occurrence burn through defects in the case of welding a thin steel sheet can be prevented, and which is excellent in gap weldability and arc stability and less in the generation of spotless so that sound welding is possible even in a joint having a wide gap. SOLUTION: A steel wire having a composition containing, by mass, ≤0.20% C, 0.25 to 2.5% Si, 0.45 to 3.5% Mn, ≤0.050% P and 0.05% S is used as a straight polarity. Welding is performed using a shield gas containing ≤98 vol.% Ar in the ranges where welding current satisfies 50 to 300 A, welding voltage E satisfies EL≤E≤EH, and welding velocity satisfies 20 to 250 cm/min. COPYRIGHT: (C)2002,JPO

Gas-shielded arc welding for steel sheet

PROBLEM TO BE SOLVED: To propose a method for manufacturing a spot welded joint having a nugget of a required size without the occurrence of expulsion and surface flash. SOLUTION: In welding a plate set formed by superposing a plurality of metallic plates on each other, spot welding comprising two stages; a first stage and a second stage, is employed and the welding of the second stage is composed of the welding of a lower current and longer weld time with a higher pressure force as compared with the welding of the first stage, The welding of the first stage in which the pressure force P I , the welding current I I and the weld time T I in the relation of the thickness (mm) of the thinnest metal among the plurality of the metallic plates satisfy 0.8tm≤P I ≤5tm, 3tm+5≤I I , 2≤T I ≤6 (where tm: the thickness (mm) of the thinnest metallic plate among the plurality of the metallic plates) and the welding of the second stage in which the pressure force P II , the welding current I II and the weld time T II satisfy 1.1P I ≤P II ≤10P I , 0.51 I ≤I II ≤I I , T I ≤T II ≤10T I are preferably employed. As a result, the spot welded joint having the nugget diameter of the required size without the occurrence of of the expulsion and surface flash is obtained. COPYRIGHT: (C)2005,JPO&NCIPI

Method for manufacturing resistance spot welded joint

PROBLEM TO BE SOLVED: To provide welding wire with which, while mechanical properties of deposited metal are secured in welding conditions of high heat input-high interpass temperature in which efficiency is regarded as most important, satisfactory welding operability is secured as well in the low heat input welding condition in which welding defects are easily generated since there is a limitation in heat input such as horizontal welding is simultaneously satisfiable. SOLUTION: This wire for carbonic acid gas shielded arc welding has a composition including a plated layer, by mass, 0.005 to 0.09% C, 0.65 to 1.2% Si, 1.5 to 2.2% Mn, 0.15 to 0.30% Ti, 0.0005 to 0.0025% B, ≤0.5% Cu, 0.0001 to 0.0030% K and 0.005 to 0.025% S, and the balance substantially Fe, also CE(1) is controlled to ≥0.45%, and KEQ to 0.02 to 0.10; wherein, KEQ=(50×K +0.5×S)/(Ti+Si+Al), and CE(1)=C+Mn/6+Si/24. COPYRIGHT: (C)2002,JPO

Shuichi Sakaguchi

Papers

Steel wire for gas shielded arc welding

Steel wire for MAG welding and MAG welding method using the same

Gas-shielded arc welding for steel sheet

Method for manufacturing resistance spot welded joint

Wire for gas shielded arc welding