What material do open wrenches use?
Recommended heat treatment temperature:1, normalizing 850, quenching 840, tempering 600.2, No. 45 steel quenched without tempering before, hardness is greater than HRC55 (up to HRC62) qualified. The highest hardness of the actual application is HRC55 (high frequency quenching HRC58).3 and No. 45 steel shall not use carburizing and quenching heat treatment process.
45 steel is the term "GB", also called "oil steel"". Hot spot in the market; cold rolled gauge 1.0~4.0mm.
The open spanner is made of 45# medium carbon steel.
