32results about How to "Improve weld toughness" patented technology

The invention provides a welding method for NM400 wear-resistant steel. The welding method comprises the following steps: after adopting an A407 stainless steel electrode as a bottoming welding joint, locally preheating the welding joint and the area in peripheral 200mm scope, wherein the preheating temperature is 350-400 DEG C and the temperature is kept constant for 5 minutes; performing multilayer multichannel welding by using an ER50-6 welding stick matched with CO2 gas protection welding, wherein the height of each layer of welding joint is not more than 4mm and the interlayer temperature is controlled to be above 150 DEG C; using the A407 stainless steel electrode for welding a transition layer at the height of 2-3 layers of welding joints from the surface of a base metal, wherein the thickness of the transition layer is more than 3mm; lastly, using a D212 electrode for covering and polishing the surplus height of the welding joint and welding toe, wherein the surplus height of the welding joint is not more than 3mm. Preheating before welding is not required, heat insulation after welding is not required, the welding technique is simple and the cost is low. The toughness of an NM400 wear-resisting steel welding joint is improved and the integration of the strength, toughness and wear-resistance of the joint is realized.

The invention discloses a P92 steel submerged arc welding wire, which contains the following chemical components in percentage by mass: 0.06 to 0.08% of C, not less than 0.40% of Si, 0.4-1.0% of Mn, not less than 0.015% of P, not less than 0.015% of S, 9.0 to 10% of Cr, 0.3 to 0.6% of Mo, 0.15 to 0.25% of V, 1.5 to 2.0% of W, not less than 0.6% of Ni, 0.03 to 0.07% of Nb, 0.8 to 1.0% of Co, 0.001to 0.05% of B, 0.03 to 0.07% of N, and the balance of Fe. The welding wire is used in the submerged arc welding, on the premise of guaranteeing high temperature performance of a welding joint, the toughness of a weld seam is increased, and the application of a highly efficient welding method of the submerged arc in the boiler production is ensured.

The invention discloses a preparation method of delta-ferrite-containing TRIP (transformation induced plasticity) steel, and belongs to the technical field of high-strength steel for automobiles. The delta-ferrite-containing TRIP steel comprises the following chemical components in percentage by mass: 0.24-0.28% of C, 0.5-1.0% of Si, 1.8-2.5% of Mn, 2.9-3.7% of Alt, no more than 0.01% of P, no more than 0.008% of S+N and the balance of Fe and inevitable impurities. The preparation method comprises the following steps: hot rolling, induction heating, ultra-fast cooling and heat treatment. The steel structure disclosed by the invention contains delta-ferrite, thereby improving the weldability. During composition design, the Al content is increased, thereby obtaining high elongation percentage, lowering the density of the steel, and effectively realizing lightweight development. The structure of the steel finished product comprises alpha-ferrite, delta-ferrite, bainite, thin-film retained austenite (or martensite / austenite island), wherein the volume percent of the retained austenite is 11.31-13.39%. The yield strength of the steel is 486-516 MPa, the tensile strength is 729-799 MPa, the elongation percentage is 28.2-29.8%, and the product of strength and elongation is 20.6-23.8 GPa.%.

The invention discloses a welding method for a steel gear assembly with a low-carbon alloy structure, relates to the field of fusion welding for steel with an alloy structure, and aims at solving the problem of the need of a pre-welding heating step and a post-welding heat insulation step during an existing welding process for a gear assembly. According to the welding method disclosed by the invention, a U-shaped groove is designed, a mixed gas of argon gas and carbon dioxide is used as protective atmosphere, flux-cored wires are used as welding materials, and welding for the gear assembly is completed through two welding guns which are symmetrically arranged during a rotation process. The welding method disclosed by the invention is used for welding a clutch shell and a gear into the gear assembly.