Microalloyed steel
Microalloyed steel is a type of alloy steel that contains small amounts of alloying elements ( 0 . 05 to 0 . 15% ) , including niobium , vanadium , titanium , molybdenum , zirconium , boron , and rare-earth metals . 
<triplet> Microalloyed steel <subj> alloy steel <obj> subclass of