How to choose the shape of the section?

The reasonable shape of the alley is to make the structure in a good stress state under different formation pressure conditions. It can ensure the safety of the roadway and the most economical materials, and at the same time, the section excavation works are the least and easy to construct.

It is now generally considered that an elliptical arch is a reasonable shape of a roadway, followed by an arc arch.

Magnetic Polishing Needles

Different with Stainless Steel Shot or Steel Shot, Magnetic Polishing Needles is not used for shot blasting and it is used for grind which could help parts have a mirror surface. For some irregular shape parts, it also have a great effects. It is widely used for precision die casting parts for deburring, removing oxide film, rust removal treatment.