A kind of martensitic heat-resistant steel electrode for 650 ℃ ultra-supercritical thermal power unit with single-sided welding and double-sided forming without argon filling on the back

Abstract

The invention discloses a martensitic heat-resistant steel welding rod for argon-free one-sided welding and double-sided forming for 650°C ultra-supercritical thermal power units on the back, using CaO‑CaF 2 -TiO 2 -Zr 2 o 3 Slag-based formula, the main component of the deposited metal is 9%Cr‑3%W‑3%Co. The invention has excellent single-sided welding and double-sided forming welding process performance. During welding, the coating of the electrode will melt to form a thin layer of slag that penetrates to the back of the workpiece and evenly covers the surface of the weld on the back to protect the weld from oxidation. And it is easy to clean the slag. Under the heat treatment conditions of 100℃×1h+780℃×3h, the tensile strength of the deposited metal is ≥720MPa, and the elongation of the deposited metal and the impact performance at room temperature are particularly excellent ≥150J, which is especially suitable for ultra-supercritical steam at 650℃ Argon-free single-sided welding and double-sided forming on the back of thermal power units are required.

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 argon-free single-sided welding and double-sided forming for 650°C ultra-supercritical thermal power units. 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 main "bo...

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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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