The difference between high-pressure boiler tubes and ordinary steel pipes

Posted by zora li on January 24th, 2024

The difference between high-pressure boiler tubes and ordinary steel pipes

Boiler tubes are seamless pipes. The manufacturing method is the same as that of seamless pipes, but there are strict requirements for the type of steel used in manufacturing steel pipes. According to the operating temperature, it can be divided into general boiler tubes and high-pressure boiler tubes.

The mechanical properties of steel are important indicators to ensure the final performance (mechanical properties) of steel. This depends on the chemical composition and heat treatment of the steel. In steel pipe standards, tensile properties (tensile strength, yield strength or yield point, elongation), hardness and toughness indicators and required high and low temperature properties are specified according to different usage requirements.

Differences in manufacturing methods:

① The working temperature of general boiler tubes is below 450°C. Domestic pipelines mainly use No. 10 and No. 20 carbon (C) bonded steel heat pipes or cold drawn pipes.

②High-pressure boiler tubes are often used under high temperature and high pressure conditions. Under the action of high-temperature flue gas and water vapor (referred to as water vapor), pipes will be oxidized and corroded. Steel pipes are required to have high lasting strength, high oxidation and corrosion resistance, and good structural stability.

Usage differences:

① General boiler tubes are mainly used to manufacture water wall tubes, boiling water tubes, superheated steam tubes, superheated steam tubes for locomotive boilers, large and small smoke tubes, arch brick tubes, etc. The large-diameter, thick-walled base material steel pipe undergoes complex physical and chemical reactions with the molten plating bath to form a corrosion-resistant zinc-iron alloy layer with a dense structure. The alloy layer is integrated with the pure zinc layer and the steel pipe matrix. Therefore, it has strong corrosion resistance.

② High-pressure boiler tubes are mainly used to manufacture high- and ultra-high-pressure boilers such as superheater tubes, reheater tubes, air tubes, and main steam tubes. Boiler steel pipe manufacturers are flat steel products made by pouring, cooling and pressing molten steel. It is a flat rectangular shape that can be rolled or cut directly from wide steel strip. According to the rolling method, it is divided into hot rolling and cold rolling.