Macrea T.,IPROLAM Bucharest |
Macrea D.,IPROLAM Bucharest |
Cuida O.,IPROLAM Bucharest |
Simion M.,IPROLAM Bucharest
Metalurgia International | Year: 2010
This paper describes the calculation algorithm of the forces and piston pressures which appear during the mechanical expanding process of SAWL pipes, in order to perform the seizing of the outer diameter of the large dimension pipes, most of them being longitudinally welded. The calculation algorithm is exemplified by its application on the calculation of the forces and piston pressures which intervene during the expanding of the longitudinally submerged arc welded (SAWL) large dimension pipes (Ø1067x11.3 mm, grade X60, Ø1219 x20.6.3 mm, grade X65 and Ø1219x30.0 mm, grade X65), as function of the following parameters: pipe dimensions, yield strength, the wedge slope angle and the friction coefficients between the expanding jaws and the wedges (μ1) between the expanding jaws and the intermediate ring (μ2) and between the expanding jaws and the inner pipe surface being expanded (μ3). In order to evaluate the conditions under which the presented calculation of the expanding piston pressure corresponds to the result obtained from the industrial practice, measurements of the pressure have been done during the expanding operation applied of the above mentioned pipes. By comparing the calculation results with those obtained from the experimental measurements, we found out that a good correspondence appears when the used friction coefficients are: μ3 of about 0.30, μ1 is approximately half of the coefficient μ3 and μ2, about 0.20.