| 摘要 |
<p>The present invention relates to a method for manufacturing a pipe for a pillar used for a pillar of a street light, a traffic signal, or a traffic sign board. Disclosed is the method for manufacturing a pipe for a pillar having the excellent corrosion resistance since the surface consists of a stainless steel material. The present invention provides the method for manufacturing a pipe for a pillar using hydroforming comprising: a mold preparing step for preparing a mold having a forming groove corresponding to a final shape of a pipe for a pillar; a material preparing step for preparing an inner pipe consisting of a carbon steel material, and whose thickness is 2-10 mm, and an outer pipe consisting of a stainless steel material, having the internal diameter is bigger than the outer diameter of the inner pipe, and whose thickness is 0.5-1 mm; and a hydroforming molding step for expanding the inner pipe as a shape corresponding to the forming groove of the mold by injecting a pressure fluid into the inner pipe while the inner pipe is arranged inside the mold after inserting the inner pipe into the outer pipe.</p> |
