Submarine oil-transportation monolayer heat-insulating pipe joint and processing method thereof

The invention discloses a submarine oil-transportation monolayer heat-insulating pipe joint which sequentially comprises a steel pipe, an anticorrosive heat-shrinkable layer, a filling layer, a mould layer and an external coating layer from inside to outside. The filling layer is made of polymer hollow micro-bead or glass micro-bead compound enhanced type polyurethane heat-insulating material, and the mass part ratio of polyisocyanate to polyether polyol as raw materials of the polymer hollow micro-bead or glass micro-bead compound enhanced type polyurethane heat-insulating material is 1.05:1, wherein polymer hollow micro-beads or glass micro-beads account for 12 percent of the polyether polyol; the mould layer is in a land prefabricated structure and is made of polyurethane foam material; and the external coating layer made of polyethylene base material is coated on the external surface of the mould layer. A processing method of the joint comprises the following steps of: 1. welding a pipeline joint; 2. inst