It is mild steel but now a days steel is being used with improvement in chemical composition of mild steel such that steel has better tensile strength.The mild steel used now has high yield strength.The high yield steel is in twisted form & it is called HYSD 415 & 500.High yield strength deformed bar having 415N/mm^2 & 500N/mm^2 yield strength.Earlier Plain mild steel bar were having 250N/mm2 yield strength .HYSD steel is also prepared by the thermo- mechanically treatment .Such steel are called TMT bar.

Stainless steel

its mild steel (MS)...not stainless steel (SS)...SS cost much more than MS and MS serves the purpose of RCC construction...that is to give good compressive strength to the beams / pillars...it has more compressive strength than SS..

tor steel

not stainless steel