To provide weld metal that has a high strength and toughness in the as-welded condition or in the annealed condition. The weld metal of the present invention contains by weight %, C: 0.04-0.15%, Si: 0.50% or less, Mn: 1.0-1.9%, Ni: 1.0-4.0%, Cr: 0.10-1.0%, Mo: 0.20 to 1.2%, Ti: 0.010-0.060%, Al: 0.030% or less, O: 0.15-0.060%, N: 0.010% or less, Fe and inevitable impurities as the remaining contents. The weld metal is further characterized by the fact that the ratio of Ti content (%) to Si content (%) i.e.,[compound type Ti]/[compound type Si] is more than 1.5, and the number A defined by the following formula is 0.50 or more, wherein A=[Ti]/([O]−1.1×[Al]+0.05×[Si]).

Weld metal and welded structure having weld joints using the same

The invention discloses a union melt welding process for steel Q420GJC for building structures. Welding materials include a welding wire MCJ55GJ with a diameter being phi 4.0mm and a welding flux SJ101; a welding environment temperature is higher than or equal to -10 DEG C; a preheating temperature is 100-150 DEG C; multi-layer and multi-pass welding are adopted, and an interlayer temperature is not lower than the preheating temperature. Conditions of backing weld include that a welding current is 520-530A, a welding voltage is 28-30V, a welding speed is 34-35.5cm/min, and thermal input is 21.3-22.8KJ/cm. Conditions of filling weld include that a welding current is 530-540A, a welding voltage is 30-32V, a welding speed is 36-37cm/min, and thermal input is 22.5-23.8KJ/cm. Conditions of cosmetic weld include that a welding current is 535-545A, a welding voltage is 28-30V, a welding speed is 34-35cm/min, and thermal input is 22.4-23.8KJ/cm. By the union melt welding process, equality in mechanical property of welds and base materials can be realized so as to meet requirements on engineering welding quality, and a gap of union melt welding of the steel Q420GJC is filled.

Union melt welding process for steel Q420GJC for building structures

PROBLEM TO BE SOLVED: To provide a weld metal with excellent toughness even at low temperatures around -20°C in high heat input welding of ≥50kJ/cm.SOLUTION: The submerged arc welding is executed by using a solid wire having a composition containing C: 0.01-0.18%, Si: 0-0.15%, Mn: 1.7-2.8%, Al: 0.02-0.1%, while N being regulated to be ≤0.01%, and the balance Fe with inevitable impurities, and bond flux containing SiO: 4-22%, AlO: 2-12%, TiO: 5-26%, MgO: 8-42%, CaF: 2-11%, CaO: 2-9%, metal carbonate (COcorresponding value): 1-7%, BO: 0.2-0.9%, Mo: 0.1-0.7%, Fe: 5-25%, and Al: 0-1.2% with respect to the total flux.

Material and method for submerged arc welding

PROBLEM TO BE SOLVED: To provide a weld metal having excellent strength and toughness even as welded or after stress relief annealing, and a weld structure joined by the weld metal. SOLUTION: The weld metal has a composition composed of, by mass, 0.04-0.15% C, ≤0.50% Si, 1.0-1.9% Mn, 1.0-4.0% Ni, 0.10-1.0% Cr, 0.20-1.2% Mo, 0.010-0.060% Ti, ≤0.030% Al, 0.015-0.060% O, and ≤0.010% N, and the balance Fe with inevitable impurities. Further, when the content (%) of one element X is expressed by [X], the ratio of the Ti amount (%) to the Si amount (%), each contained as a compound, i.e., [compound type Ti]/[compound type Si] is >1.5, and the value A calculated by formula A=[Ti]/([O]-1.1×[Al]+0.05×[Si]) is ≥0.50. COPYRIGHT: (C)2011,JPO&INPIT

Weld metal having excellent strength and toughness as welded and after stress relief annealing, and weld structure joined by the weld metal

The present invention provides a bonded flux for submerged arc welding, which can obtain welding metal with high welding operability and high toughness even though welding construction for low-temperature steel is carried out by means of a narrow groove The bonded flux for submerged arc welding contains 25-45 mass% of MgO, 5-25 mass% of Al_2O_3, 5-25 mass% of CaF_2, 2-10 mass% of metal carbonates, total 2-10 mass% of CaO and/or BaO, total 2-10 mass% of at least one among metal Si, Si alloy, and Si oxide, total 03-20 mass% of at least one among metal Ti, Ti alloy, and Ti oxide, total 005-03 mass% of at least one among metal B, B alloy, and B oxide, and 0005-015 mass% of S; and moreover, the total content of metal Al and Al alloy is limited below 01 mass% Additionally, the total content of metal Si and Si alloy is 03-20 mass%, and the total amount of Si/Ti is in the range of 5-15

Bonded flux for submerged arc welding

PROBLEM TO BE SOLVED: To provide a submerged arc weld metal of high tensile strength steel having a tensile strength of ≥900 MPa, which is subjected to multilayer build up welding by submerged arc welding in the combination of solid wire and bond flux, from which satisfactory strength and stable toughness can be obtained, and whose working property in welding is satisfactory, and which is free from welding defects. SOLUTION: The submerged arc weld metal of high tensile strength steel obtained by being subjected to multilayer build up welding by submerged arc welding in the combination of solid wire and bond flux has a composition comprising per total mass of the weld metal, by mass, 0.04 to 0.09% C, 0.20 to 0.35% Si, 1.6 to 2.3% Mn, 2.5 to 3.0% Ni, 0.55 to 1.0% Cr and 0.55 to 1.0% Mo, and comprising ≤0.20% Cu, ≤0.022% O and ≤0.006% N, and the balance Fe with inevitable impurities. COPYRIGHT: (C)2008,JPO&INPIT

悟西村

Papers

Submerged arc weld metal of high tensile strength steel

悟 西村

Papers

Submerged arc weld metal of high tensile strength steel

悟西村