Mechanical welding process of high alloy steel for boiler tube screen

Abstract

A mechanical welding process of high alloy steel for a boiler tube screen comprises the following step (1) of preheating before welding; the step (2) of regulation of the relative position between fins and a tube; the step (3) of welding parameters; and the step (4) of slow cooling after welding. According to the mechanical welding process, through analysis on the welding performance and influence factors of materials, and the measures of regulation and improvement of welding equipment, change of a preheating method, increase of slow cooling after welding and the like, the problems of poor welding performance of SA213-T91 materials, high temperature sensitivity, easy occurrence of cracks after welding and the like are solved. The effective measures of large-batch intensive high-quality weld joints are ensured, and the primary product yield is improved by 30% and above; and the market competitiveness of an enterprise is improved greatly.

Description

technical field [0001] The invention relates to the technical field of thermoelectric boiler technology, in particular to an anti-crack welding process for fillet welds of T91 high-alloy steel pipes used for boiler tube panels. Background technique [0002] With less and less international energy sources and the impact of energy consumption on the environment, people's requirements for thermal efficiency, low carbon emissions, and harmful substance control of coal power projects are also changing rapidly; for this reason, the current technical performance and parameters of coal power Fundamental changes have also taken place. The requirements for large units, large capacity, high performance, high efficiency, and low emissions have forced coal-fired units to continuously update the indicators of high parameters and low emissions, especially for high-grade materials such as SA213-T91 in boilers. It has been widely used in boiler heating surface tube screens, but high-alloy st...

AI Technical Summary

Problems solved by technology

[0002] With less and less international energy sources and the impact of energy consumption on the environment, people's requirements for thermal efficiency, low carbon emissions, and harmful substance control of coal power projects are also changing rapidly; for this reason, the current technical performance and parameters of coal power Fundamental changes have also taken place. The requirements for large units, large capacity, high performance, high efficiency, and low emissions have forced coal-fired units to continuously update the indicators of high parameters and low emissions, especially for high-grade materials such as SA213-T91 in boilers. It has been widely used in boiler heating surface tube screens, but high-alloy steels such as t91 have poor weldability, high alloy elements, and strong carbonization elements. If the preheating before welding is not good, hot cracks tend to appear after welding, and Continuous multi-pass welding is used in the mechanical welding process, and the interlayer temperature is prone to be too high.

[0003] It brings great challenges to the difficulty of making the tube panel. The material has poor welding performance, strong temperature sensitivity, and cracks are prone to occur after welding.

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