1. CHEMICAL COMPOSITION
„P540“ is a special nonmagnetic, austenitic Mn-Cr-N-steel with a nitrogen content of ≤ 2%.
|max. 0,05||19,00 - 21,00||17,00 - 19,50||0,30 - 0,80||min. 0,50||0,80 - 2,00|
2. MECHANICAL PROPERTIES
Following mechanical properties (tested at room temperature) are achieved by a special cold-working process over the full length of the collar:
|Yield Strength (min.) 0,2%-offset method:||OD up to 9 1/4“||120 ksi||830 N/mm²|
|OD 9 1/2“ and larger||110 ksi||760 N/mm²|
|Tensile Strength (min.):||130 ksi||900 N/mm²|
|Reduction of area (min.):||50%||50%|
|Impact energy (min.):||90 ft.lb||122 J|
|Endurance Strength / N=10⁵ (min.):||± 65 ksi||± 455 N/mm²|
|Hardness Brinell: (min.):||285-400 HB||285-400 HB|
3. MAGNETIC PROPERTIES
Relative permeability: ≤ 1,005.
4. CORROSION RESISTANCE
• Transgranular SCC: Prevented by special surface treatments (Hammer peening, roller burnishing, shot peening).
• Intergranular SCC: The occurrence of material sensitization is prevented by quenching after warmforging. Each collar is tested according to ASTM A 262, Pract.A and E, last edition.
• Pitting Corrosion: Due to a high chromium- and nitrogen content a high resistance to pitting corrosion is given.
5. NON-DESTRUCTIVE TESTING
• Magnetic inspection: Drill collars are 100% tested by a proprietary probe-testing process using a Förster Magnetomat 1.782. (“Hot Spot“-test). Magnetic permeability of each collar is certified with the printout of probe-testing.
• Ultrasonic inspection: Each collar is ultrasonically inspected over 100% of the volume according to ASTM E 114, last edition as a minimum level.