| 摘要 |
<p>Steel rod or bar comprises an outer surface layer of ferrite-pearlite type structure, an annulus immediately below the layer having an acicular micro-structure comprising martensite and/or bainite and a core of bainite or martensite or ferrite and carbides or a combination of two or more or ferrite and carbides or a combination of two or more of these constituents. The outer layer of ferrite-pearlite has greater resistance to stress corrosion than conventional couter layers of martensite or bainite.</p> |
