METHOD FOR MAKING UPSET ENDS ON METAL PIPE AND RESULTING PRODUCT

摘要

A method for making an internal upset (20A) on metal drill pipe (10) having a transition section (24A) with a curved inner periphery (28A) of a concave curvature extending continuously between the central portion (12) of the pipe (10) and the increased thickness end section (22A) and formed from a radius (R2). An external upset (20) is first formed in forging steps as shown in Figures 2 and 4 by radially expanding and squeezing the end of pipe (10). Then the final forging step radially contracts the external upset (20) to form the internal upset (20A) as shown in Figures 3 and 5. The finished internal upset (20A) as shown in Figure 7 has a transition section (24A) with an inner peripheral curved surface (28A) formed from a radius (R2). The forging steps are performed with a single heating of the metal drill time in a minimum of time preferably within around one (1) minute but in any event less than around two (2) minutes.