Super-long thermal insulation steel jacket pipe and machining process thereof

A machining process for producing a super-long thermal insulation steel jacket pipe, comprising:

• (1) cleaning a surface of a steel plate used to define a working steel pipe;
• performing crimping and laser welding;
• performing heat treatment after the working steel pipe is obtained through welding;
• and performing sizing and non-destructive testing on the working steel pipe;
• (2) making a support frame defined by one of the following:
• a spiral annular support frame sleeved on an outer peripheral side of the working steel pipe, and C-shaped support frames that wind the outer peripheral side of the working steel pipe at intervals, wherein the spiral annular support frame is not in contact with the working steel pipe;
• (3) cleaning a surface of a steel plate used to define an outer steel pipe;
• performing crimping while wrapping the working steel pipe whose outer surface is provided with the support frame, wherein the support frame tightly supports an inner wall of the outer steel pipe;
• then performing laser seal welding to form a jacket pipe;
• performing heat treatment on the jacket pipe;
• and performing sizing and non-destructive testing on the fabricated outer steel pipe, wherein a thickness of an annular cavity between the outer steel pipe and the working steel pipe is 2 mm to 7 mm;
• (4) placing a phase-change energy storage material in the annular cavity of the jacket pipe;
• then placing several rubber rings at a tightened end of the outer steel pipe for sealing, and performing vacuumizing treatment on the annular cavity to make the annular cavity become a vacuum cavity;
• and finally performing solder sealing on the tightened end of the outer steel pipe;
• and
• (5) performing heat treatment at 50° C. to 280° C. for 30 min to 60 min on a steel jacket pipe fabricated in step (4), cooling, and coating anti-corrosion liquid outside the steel jacket pipe, that is, obtaining the insulation steel jacket pipe.