① Due to the irregular inner surface of the outer base pipe, the wall thickness of the outer base pipe is uneven.
Restricted by the basic formation of the bimetallic composite pipe, the outer base pipe should be in the elastic deformation range, and the uneven wall thickness of the outer base pipe will limit the amount of explosives in mass production. When the dose is large, the shock wave is large in an instant, and the outer base tube is prone to permanent deformation, or even unsafe, so that the bonding force decreases; The metal composite pipe has a small bonding force. Usually about 0.5 MPa. Due to the characteristics of the explosion forming process, the liner tube shrinks inward in the axial direction. In order to ensure the roundness of the nozzle, a secondary correction has to be carried out.
② Due to the small bonding force, the gap between the annular joint surfaces of the inner and outer pipes is large, and the inner lining pipe will be repeatedly subjected to the twisting and bending of the alternating pressure during the medium conveying process at the welding point of the pipe end, resulting in material fatigue and bending at the joint. Cracking, resulting in decreased corrosion resistance - (warping phenomenon).
③ Due to the limited amount of explosives charged, the lining pipe cannot achieve sufficient plastic deformation. Due to the small reaction force generated by the shock wave, the compressive stress on the inner surface of the lining pipe cannot be fully reflected, and the straight seam welding of the lining pipe is still in a state of tensile stress. As a result, the overall surface of the lined pipe, especially the straight seam weld, has a reduced ability to resist thermal stress corrosion.
Representative manufacturer: unknown
Hydraulic compound method
Formation mechanism:
Completely seal the assembled inner and outer tubes - a long closed tube, and then inject the liquid into the tube to gradually pressurize the liquid in the tube, so that the inner lining tube gradually expands outward in the diameter direction and contracts inward in the axial direction. Through continuous and gradual pressure application, the inner lining pipe finally reaches plastic deformation, and the outer base pipe is still in the elastic deformation range. form.
Features:
① Step by step pressure forming.
② The pressure at each point in the closed long cylinder is the same.
③ Do not damage the stainless steel surface of the inner tube
④ Suitable for large-diameter bimetallic composite pipe composite work
⑤ The high-pressure hydraulic compound makes the bonding strength far higher than the industry standard
technical parameter:
Base pipe type: seamless steel pipe, straight seam welded pipe or spiral welded pipe and food grade 304 stainless steel pipe
Compound pressure: the bonding strength is higher than the 0.2MPa required by the industry standard
Execution standard: the operating pressure conforms to the provisions of GB/T8163-2008 and GB/T3091-2008
Connection Type: Welded and Flanged
Product Usage:
Widely used in water affairs, water conservancy and hydropower engineering, petrochemical engineering, gas engineering, fire engineering, school hospital, industrial and civil construction engineering, etc.
Representative manufacturers:
