Kelly is the drive part of whole drill stem, it has two types, square kelly and hexagonal kelly and all of them are manufactured comfort to API Spec7- 1 and SY/T6509- 2000 criterion .
Our Square& Hexagonal kelly are made from AISI 4145H modified alloy bars that are quenched and tempered full length . After such heat treatment, its brinell hardness can reach 285-341. Kelly's end, drive cross-section and joint are all processed and tested conform to API criterion .
Specification of Kelly
Norminal Size | Length (ft) | Top Upset Joint | Bottom Upset Joint | Bore D | Drive Section |
(in) | API BOX | Du | Right Hand Connections | DL | Across | Across |
| Thread Left Hand | Corners | Flates |
2003/1/2 | 40 | 6 5/8REG | 7 3/4 | NC38(3 1/2IF) | 4 3/4 | 2 1/4 | 4.437 | 3 1/2 |
2004/1/4 | 40 | 6 5/8REG | 7 3/4 | NC46 (41F) | 6~6 3/8 | 2 13/16 | 5.5 | 4 1/4 |
NC50(4 1/2IF) | 6 1/8~6 3/8 |
2005/1/4 | 40 | 6 5/8REG | 7 3/4 | NC50 | 7 | 3 1/4 | 6.75 | 5 1/4 |
5 1/2FH |
6 | 40 | 6 5/8REG | 7 3/4 | NC50 | 7 3/4 | 3 1/2 | 7.625 | 6 |
