Some seamless pipes need shrinking and flaring to produce products. The shrinking and flaring of seamless steel pipes is a forming process in which the mouth of the pre-formed steel pipe is reduced and enlarged through the shrinking and flaring dies.
Hot Extrusion Technology of Seamless Tube Shrinking and Flaring
(1) Shrinking and flaring hot extrusion means that the steel pipe is heated to above the specified temperature, and the plasticity is good under its hot state. Equipment used: super audio, forging machine, necking machine, belling machine and other extrusion molding.
(2) Thermal shrinking process: port heating → rough forging → rolling extrusion compression → natural cooling → car port (this is one end shrinking, two ends shrinking repeat the above process).
(3) Thermal flaring process: port heating → rolling extrusion flaring → natural cooling → car port (this is one end flaring, two ends flaring repeat the above process).
Shrinking and expanding cold extrusion process
(1) Shrinking and flaring cold extrusion process is to push the mold hydraulically and directly extrude the nozzle to form.
(2) Equipment used: double-station shrinking and expanding machines, shrinking molds, and expanding molds.
(3) One-end necking and flaring process: lubricating oil on the mold and nozzle → squeeze the nipple, flaring → car port.
(4) The technological process of necking and flaring at both ends: lubricating oil on the mold and port→squeeze the mouth and flaring→turn around and fine-tune the positioning block (there is a certain extension and shortening of the length)→lubricating oil on the mold and port→Squeeze the mouth, flaring → car port.
(5) The number of necking times is determined by the material. It takes two to enable the duplex bit.
Confirmation of shrinking and flaring times
(1) Due to the lack of effective calculation formulas, the principle of shrinkage and expansion times can be determined based on actual experience. The axial pressure required for necking and flaring deformation does not make the material yield, no plastic deformation occurs, and it is completed at one time. The axial pressure required for deformation makes the material yield, plastic deformation occurs, and the material will bulge out of shape. It should be divided into two times, the differentiation axial pressure is less than the yield of the material. This principle is also to determine whether a material conforms to the process.
(2) Considering factors such as material work hardening and increased frequency of production, equipment costs, etc., the number of necking should not be too much, and only twice at most.
Hot Extrusion Technology of Seamless Tube Shrinking and Flaring
(1) Shrinking and flaring hot extrusion means that the steel pipe is heated to above the specified temperature, and the plasticity is good under its hot state. Equipment used: super audio, forging machine, necking machine, belling machine and other extrusion molding.
(2) Thermal shrinking process: port heating → rough forging → rolling extrusion compression → natural cooling → car port (this is one end shrinking, two ends shrinking repeat the above process).
(3) Thermal flaring process: port heating → rolling extrusion flaring → natural cooling → car port (this is one end flaring, two ends flaring repeat the above process).
Shrinking and expanding cold extrusion process
(1) Shrinking and flaring cold extrusion process is to push the mold hydraulically and directly extrude the nozzle to form.
(2) Equipment used: double-station shrinking and expanding machines, shrinking molds, and expanding molds.
(3) One-end necking and flaring process: lubricating oil on the mold and nozzle → squeeze the nipple, flaring → car port.
(4) The technological process of necking and flaring at both ends: lubricating oil on the mold and port→squeeze the mouth and flaring→turn around and fine-tune the positioning block (there is a certain extension and shortening of the length)→lubricating oil on the mold and port→Squeeze the mouth, flaring → car port.
(5) The number of necking times is determined by the material. It takes two to enable the duplex bit.
Confirmation of shrinking and flaring times
(1) Due to the lack of effective calculation formulas, the principle of shrinkage and expansion times can be determined based on actual experience. The axial pressure required for necking and flaring deformation does not make the material yield, no plastic deformation occurs, and it is completed at one time. The axial pressure required for deformation makes the material yield, plastic deformation occurs, and the material will bulge out of shape. It should be divided into two times, the differentiation axial pressure is less than the yield of the material. This principle is also to determine whether a material conforms to the process.
(2) Considering factors such as material work hardening and increased frequency of production, equipment costs, etc., the number of necking should not be too much, and only twice at most.
