... Rig Type : zp375, zp275,zp205, zp175 Gleason Spiral Bevel Gear for Oil Drilling Rigspiral bevel gear features:1) Material: 42CrMo, 20CrMnMo, 20Cr2Ni4, 35CrMo ... , 20CrMnTi and according client request .2) Heat treatment : ring gear Q+T and HB 270-320 pinion nitrification and Hv ... 800 and hardness deep 0.7-0.8 mm3) Gear precision: class 6 Gleason Spiral Bevel Gear