Standard: API Spec 7-1
Specification: Square Kelly size: 2 1/2”---6”
Hexagonal Kelly size: 3”----6”
Steel Grade: AISI 4145H Alloy Steel
Usage: Kelly is the drive section of the whole drill-stem.
Description:
Kellys are made from 4145H modified alloy steel in accordance with API Spec.7-1 latest edition, which are quenched and tempered along full length. A hardness range of 285 to 341 BHN and a minimum impact value of 54 Joules as per ASTM A 370 Charpy-V, these values are guaranteed one inch below the surface. SFMC Kelly bars are inspected by an ultrasonic unit. Over their full length and full section. The wall thickness of each flat of the drive section is verified ultrasonically on each Kelly. All Kellys connections are supplied with pressed steel thread protector on both ends and each Kelly would be shipped with protective steel scabbard.
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Mechanical Properties of Kelly |
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Bottom Upset |
Yield Strength |
Tensile Strength |
Elongation |
Brinell Hardness |
Impact AKV |
|
σb(MPA) |
σs(MPA) |
δ4(%) |
HB |
Ακ(J) |
|
|
85.7——174.6 |
≥758 |
≥965 |
13 |
≥285 |
54 |
|
177.8 |
≥689 |
930 |
13 |
≥285 |
54 |