High-silicon high-aluminium ferrite stainless steel and its application in preparation of heat-resisting steel pipe

Abstract

The present invention relates to ferrite stainless steel and its application in rolling heat resistant steel pipe. The ferrite stainless steel contains: C not more than 0.06 wt%, Cu not more than 0.30 wt%, Si 0.5-2.0 wt%, S not more than 0.030 wt%, Mn not more than 0.6 wt%, P not more than 0.030 wt%, Cr 16.0-25.0 wt%, Ti not more than 0.3wt%, Al 0.5-2.0 wt%, Ni not more than 0.60 wt%, N not more than 0.030 wt%, except Fe. During making heat resistant steel pipe with the ferrite stainless steel, temperature control mode in 100-1050 deg.c is adopted.

Description

Technical field [0001] The invention belongs to the field of ferritic stainless steel and its application in rolling heat-resistant steel pipes, and in particular relates to a high-silicon, high-aluminum ferritic stainless steel and its application field in preparing heat-resistant steel pipes. Background technique [0002] At present, in the petroleum, chemical industry, especially in various furnace industries where there are a large amount of chloride ions and sulfides, tubular heat exchangers are used at high temperatures, generally 18-8 austenitic stainless steel, The stress corrosion resistance of this type of steel is very poor, and the high temperature oxidation resistance is not good, and the surface falls off in a large area at high temperature and cannot be used. The use of Cr18 type ferritic stainless steel as a heat exchanger solves the problem of using in environments containing chloride ions and hydrogen sulfide, but it has poor oxidation resistance at high te...

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Problems solved by technology

[0002] At present, in the petroleum, chemical industry, especially in various furnace industries where there are a large amount of chloride ions and sulfides, tubular heat exchangers are used at high temperatures, generally 18-8 austenitic stainless steel, The stress corrosion resistance of this type of steel is very poor, and the high temperature oxidation resistance is not good, and the surface falls off in a large area at high temperature and cannot be used.

The use of Cr18 type ferritic stainless steel as a heat exchanger solves the problem of using in environments containing chloride ions and hydrogen sulfide, but it has poor oxidation resistance at high temperatures, and because most ferritic stainless steels It is difficult to process seamless steel pipes. Therefore, domestic petroleum, chemical industry, especially heat exchanger tube bundles in various furnaces, basically use 18-8 austenitic stainless steel tubes as heat exchanger tube bundles.

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