Mo-containing ferritic stainless steel and manufacturing method thereof

Abstract

The invention discloses Mo-containing ferritic stainless steel, which comprises the following chemical elements in percentage by mass: less than or equal to 0.025 percent of C, less than or equal to 0.025 percent of N, less than or equal to 1.0 percent of Si, less than or equal to 1.0 percent of Mn, less than or equal to 0.04 percent of P, less than or equal to 0.03 percent of S, more than 20.0 percent and less than or equal to 22.0 percent of Cr, more than 0 percent and less than or equal to 1.0 percent, less than or equal to 1.3 percent of (Ni+Cu), more than or equal to 0.5 percent and lessthan or equal to 1.2 percent of Mo, more than or equal to 10(C+N) and less than or equal to 0.8 percent of (Ti+Nb), less than or equal to 0.015 percent of O, and the balance of Fe and other inevitable impurities. Correspondingly, the invention also discloses a manufacturing method for the steel. Compared with the conventional SUS444 and SUS436L steel, the Mo-containing ferritic stainless steel has the advantages of greatly reducing manufacturing cost, maintaining pitting corrosion resistance and chlorine-ion stress corrosion resistance, and being suitable for water system medium environments.

Description

technical field [0001] The invention relates to an alloy in the field of metallurgy and a manufacturing method thereof, in particular to a Mo-containing stainless steel with good corrosion resistance and a manufacturing method thereof. Background technique [0002] At present, the stainless steel material used for solar water heaters in the Chinese market is mainly SUS304 steel. SUS304 stainless steel has excellent comprehensive properties such as plasticity, processability, weldability, uniform corrosion resistance, beautiful surface, simple and practical, which is the main reason why it can be widely used in the domestic solar water heater industry. [0003] However, the application practice of SUS304 stainless steel in solar water heaters, especially the inner tank, shows that the steel is not ideal in terms of local corrosion resistance such as pitting corrosion resistance, chloride ion stress corrosion and crevice corrosion, which leads to some insurmountable limitation...

AI Technical Summary

Problems solved by technology

Its disadvantages are that its weldability is obviously not as good as that of austenitic stainless steel, it has higher requirements for welding process and equipment, low processing efficiency, relatively poor formability of base metal and weld seam, and relatively has certain requirements for stamping die and forming process

The above reasons have led to the slow pace of the domestic solar industry, which is more sensitive to prices, to widely adopt SUS444 to replace the existing austenitic stainless steel in the inner tank of water heaters.