The test hammer test on the steel anvil vertically down to calibrate rate fixed value. The average rate fixed value of concrete test hammer is
【N】=80+2. The average rate fixed value of Mortar test hammer is【N】=74+2.
As calibration tool, when it is tested 5000-8000 times, it could put anvil core and anvil body grinding flat on the above plane. But the anvil core hardness should keep in HRC58-62.
Steel anvil usually stored in the dry and no dust place in case of rust.
