Good User Reputation for Astm A490m High Strength Steel Bolts - subway bolt,dacromet coating Curved Bolts – Ji Luo Fastener

In the tunnel construction, there is a machine called shield machine, which is used for starting and tunneling. However, the shield machine is assembled with several pieces of pipe when lining the tunnel. A screw is used to connect and tighten the pipe to form cylindrical pipe, which is a cylindrical wall. The excavation can effectively control the ground settlement, reduce the impact on the ground buildings and the underwater excavation does not affect the surface traffic, etc., the pieces of pipe are combined together to form the pipeline, which is designed as a straight or curved fastening connector, namely the piece of pipe bolts