Chainsaw Repair

When you harden carbon steel in a quench it is actually surface hardening. The core of the part stays soft. Water is used to make the hardest surface as the quickness of the cooling determines how much carbon is brought to the surface. Oil cools a little more slowly and is better for a part that needs to be a little tougher. When you need something to be wear resistant water hardened 1045 is hard to beat. Fairly easy to get Rockwell 60 on the surface. The most exotic hardening steel I have worked with is ASTM 52100 high carbon chromium bearing steel. Water hardens to over 65 Rockwell.