Brief Introduction Of Seamless Steel Pipe Piercing Process
Traditional barrel roll (or man) piercer widely used in hot-rolled seamless steel tube production. But since 1980, appeared after the conical perforation of double support, cone-shaped perforation machine for faster development. Compared to barrel roll piercer, conical perforation unit has the following characteristics.
(1) the cone roll diameter increases gradually from entry to exit, roll speed from entry to exit with the roll diameter increases gradually increased, to axial deformation of metals, and reduced the reverse of seamless tube and additional distortion, delay "cross-forging effect" (effect of Schistosoma mansoni), can improve the quality of seamless steel pipe inner surface of the capillary. Thus to the perforation and alloy steel continuous casting slab is desirable.
(2) export axial velocity is high, piercing and high efficiency.
(3) elongation coefficient is large, up to 6.
(4) expanding large amount of up to 30%~40%.
(5) the equipment weight and capacity are larger, higher investment.
Barrel roll and cone-shaped roll piercer piercing process is the same.
Punch by roller or guide disc (printed circuit boards) and composed of head deformation patterns.
Deformation of perforated into biting (ⅰ), piercing (area), are the whole paragraph (iii), planning (ⅳ region) 4 stage.
(L) bite (ⅰ)
Bite's main function is to achieve seamless steel tube a biting, for the successful realization of seamless steel tube contact head secondary to bite into, prepare for perforation.
Seamless steel tube round billets was after bite, because of entrance cone surface of roller cone along the direction of perforation (vertical) side rotate the side forward, gradually being compressed in diameter. Compressed part of the metal part to lateral flow, blank sections change from round to oval, part of the metal (mainly the surface) to the vertical extension, front end of the blank form "trumpet"-shaped depression. This SAG and centering holes (if necessary) head and billets to achieve.
(2) perforation (ⅱ)
Perforated section's primary role is solid billet into hollow seamless tube, the length from the head nose up to the head tapered.
Deformation feature of this sector is the roll surface and the surface of the head space decreases, and seamless tube rotate forward, wall thickness by compression, is a helical rolling process. Is under the pressure of the metal wall thickness, lateral movement (expansion) and vertical mobility (extension). Lateral flow deformation but limited by the Guide disk, vertical deformation is important. Because of the proactive rotation was subjected to longitudinal friction of metals, strengthened metal vertical extension, extension coefficient may reach 6 per cent.
(3) the whole (ⅲ)
Throughout the primary role is to support the whole wall, improve dimensional accuracy and surface quality of internal and external wall thickness. Length from the head tapered belt at the beginning, ending with a seamless steel tube wall leaving the head.
As head of bus bus approximately parallel and roll, wall thickness reduction is very small, main role. Seamless steel tube oval in cross section in this section.
(4) rules (zone ⅳ)
Gauge round seamless oval is the main role of capillary gauge round. The length starting from seamless steel tube wall leaving the head, ending with a seamless tube from a roll.