| 摘要 |
<p>A duplex stainless steel for use in urea manufacturing plants, in mass %, consisting of C: 0.03% or less, Si: 0.5% or less, Mn: 2% or less, P: 0.04% or less, S: 0.003% or less, Cr: 26% or more, but less than 28%, Ni: 6-10%, Mo: 0.2-1.7%, W: more than 2%, but no more than 3%, N: more than 0.3%, but no more than 0.4%, with the balance being Fe and impurities, in which the content of Cu as an impurity is not more than 0.3%. The duplex stainless steel may also have Ca, Ce, and B content, and it is desirable that levels of Al and O (oxygen) as an impurities be no more than 0.05% and 0.01% respectively. Further, it is preferable that an increase in the Vickers hardness of the steel should not be more than 80, before and after the solution treated steel is subjected to the heat treatment of 800° C. for 30 minutes and subsequent water cooling. This duplex stainless steel possesses a high corrosion resistance.</p> |
