| 摘要 |
PURPOSE:To manufacture the titled superior steel pipe at low cost by previously forming an antiplating layer contg. water as a medium on the inside of a steel pipe, plating the outside, cooling the plated molten metal, removing an antiplating agent, and coating the inside with an org. substance. CONSTITUTION:Powdered alkali carbonate is mixed with water as a medium to prepare a slurry as an easily removable antiplating agent, and this agent is applied to the inside of a steel pipe. At this time, by adding sodium silicate or colloidal silica as a binder to the water medium, the adhesion of the antiplating agent to the pipe inside is improved. After plugging both ends of the pipe, a flux is applied to the outside of the pipe by dipping into the flux, the pipe inside and outside are dried after unplugging, and the pipe outside is plated by dipping in a plating bath. After cooling the plated molten metal, the pipe inside is pickled to thoroughly remove the antiplating agent, and it is coated with an org. substance. |
