Submerged-arc welding flux for 800MPa-grade high-strength steel for large-size hydropower facility and production method of submerged-arc welding flux

Abstract

The invention discloses submerged-arc welding flux for 800MPa-grade high-strength steel for a large-size hydropower facility and a production method of the submerged-arc welding flux. The submerged-arc welding flux comprises, by mass percentage, 9-23% of CaF2, 9-14% of Al2O3, 8-18% of SiO2, 18-34% of MgO, 15-22% of CaO, 1-5% of MnO, 0.5-3% of Fe2O3, less than or equal to 2.5% of Na2O, less than orequal to 2.5% of K2O and less than or equal to 2% of TiO2. The production method comprises the steps that after the elements are uniformly mixed according to the proportions, a binding agent accounting for 15% to 20% of the total amount of the materials is added for granulation; and then, 200-250 DEG C low-temperature baking, 670-780 DEG C high-temperature sintering and sieving are conducted, sothat a submerged-arc welding flux product is obtained. According to the submerged-arc welding flux and the production method thereof, a reasonable welding process is adopted to be matched with the chemical elements of the 800MPa high-strength steel, and therefore, chemical elements and textures of metal at each welding seam can reach the optimal state; the deposited metal S and the deposited metalP are low in content, and the flux has reasonable mechanical property indexes such as the tensile strength, the impact value, the bending property, the crack resistance and the hardness; and in addition, air holes, slag inclusion and cracks inside each welding seam as well as appearance edge excessiveness, undercuts and the like meet the standard requirements.

Description

technical field [0001] The present invention relates to the supporting flux used in the welding production process of metal materials, in particular to a submerged arc welding flux for 800MPa grade high-strength steel used in large-scale hydropower and a production method thereof. Background technique [0002] In recent years, the international environmental, energy and resource competition has become increasingly fierce, and the pattern of energy supply and consumption has undergone profound changes. Driven by the national low-carbon energy-saving development trend, high-strength steel will be widely used instead of steel below 500MPa, and it will become more and more important in transportation, marine engineering and other fields. The pace of my country's hydropower construction is further accelerated, especially the construction of large-capacity pumped storage power stations in the middle and upper reaches of the Yangtze River. As an environmentally friendly and clean e...

AI Technical Summary

Problems solved by technology

Submerged arc automatic welding, as a welding method with the advantages of high deposition efficiency, large penetration depth and mechanical automatic operation, is especially suitable for the manufacture of large-scale welded structures. The grains in the affected area are coarse, which increases brittleness and reduces toughness, causing certain difficulties for the development of submerged arc welding consumables for 800MPa pressure pipes