Martensite heat resistant steel electrode for 650 DEG C supercritical thermal power unit with back side free of argon filling, single-side welding and double-side molding

Abstract

The invention discloses a martensite heat resistant steel electrode a 650 DEG C supercritical thermal power unit with a back side free of argon filling, single-side welding and double-side molding. Aslag series formula of CaO-CaF2-TiO2-Zr2O3 is adopted, and the main components of deposited metal comprise 9% of Cr, 3% of W and 3% of Co. The martensite heat resistant steel electrode has excellent single-side welding and double-side molding technological properties; during welding, an electrode coating can be molten for forming a layer of thin slag infiltrated into the back side of a workpiece and uniformly covering the surface of a weld joint at the back side so that the weld joint is protected from being oxidized; and slag is easy to clear. Under the heat treatment condition of 100 DEG Cx1h+780 DEG Cx3 h, the tensile strength of the deposited metal is not lower than 720 MPa, and the elongation and normal temperature impact property of the deposited metal are particularly excellent, and are not lower than 150 J; and the martensite heat resistant steel electrode is especially suitable for the priming requirements of the 650 DEG C supercritical thermal power unit with the back side free of argon filling, single-side welding and double-side molding.

Description

technical field [0001] The invention belongs to the field of welding materials, and in particular relates to a martensitic heat-resistant steel welding rod for a 650°C ultra-supercritical thermal power unit with argon-free backside single-side welding and double-side forming. Background technique [0002] With the large demand for electricity brought about by the rapid development of the national economy in recent years, relevant departments and enterprises urgently need to improve the efficiency of power station construction and operation, reduce costs and take into account environmental protection. Improving the steam temperature parameters of thermal power units is the most important measure to improve the thermal efficiency of the unit and realize coal saving and emission reduction. [0003] Under such conditions, the development of ultra-supercritical boiler units has become the dominant direction of power station construction. However, heat-resistant materials are the...

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Problems solved by technology

However, at present, the bottoming of the narrow gap between pipes is mainly achieved by argon arc welding. To ensure the high temperature flue gas side corrosion resistance of the weld, it is necessary to fill the pipe with argon to ensure the quality of the back weld. The process requirements are high, and the cost is high. On the other hand, the performance of solid argon arc welding wire mainly depends on the composition of the welding wire. At present, there is still a relatively broad development space for the smelting technology of G115 steel in China.

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