disc plow blade

Harrow Disc,plough blade, disc blade,plough disc,harrow disc ,Material 65 Manganese Steel ,Heating 900 span,Quenching  1+2 about 300 span
     Hardness 38 to 45 HRC ,Holes Availability 1. Square 2. Round  3.  Round with key slot 
     4. Round and square combined Types of disc  5 . Plain    6.Notched