Modification Of Non-metallic Inclusions Research Articles

低合金超強力鋼の低温機械的性質の改善

Ultrahigh-strength low-alloy steels with a medium carbon (0.25 to 0.50 mass%) content and various amounts of chromium, molybdenum, nickel, silicon, and vanadium have been needed for high-performance aerospace parts. The steels can be employed successfully at yield strengths of 1400 MPa or higher, but their commercial use is limited by their poor ductility and toughness at low ambient temperatures. Brittle fracture has to be given serious consideration at these levels. This review surveys improvement of the low temperature mechanical properties of ultrahigh-strength low-alloy steels. Particular emphasis is placed on improving the mechanical properties through mixed-structure control, thermomechanical treatments, and modification of non-metallic inclusions. The major microstructures controlling the mechanical properties are discussed for each of these techniques.

The effect of manganese on the modification of non-metallic inclusions and magnetic properties of columnar alnico 5 permanent magnets

Magnetic properties of Alnico 5 alloy of columnar structure are reviewed in terms of Mn content 0.04-0.7 wt% in the alloy. It was ascertained that all magnetic properties are affected by Mn, and deteriorate proportionally to the increased content of Mn in the alloy, the greatest changes occuring in energy product and the smallest in magnetic remanence. An increased content of Mn in Alnico 5 alloy is also responsible for a higher proportion of inclusions over 5 μm in size and the transition of inclusion from a homogeneous to a heterogeneous structure, which is an aggregate of oxides and sulphides.