At present, I want to use pneumatic wrench to screw M8.8 M30 and M24 high-strength bolts. How to choose the air pressure?

Pneumatic tools generally have gear adjustment, and each gear generally has corresponding torque parameters. In fact, gear adjustment is to control its intake flow. If the flow rate is small, the pressure on the motor is small and the torque is low. However, pay attention to your preload time, which has a lot to do with it. I'll give you a general pressure capacity table for pneumatic tools (standard pressure 6 kg):

4 kg air pressure-54% of tool capacity

5 kg air pressure-tool capacity 76%

6 kg air pressure-tool capacity 100%

7 kg air pressure-tool capacity 125%.