1. CHEMICAL COMPOSITION
„P750 “ is a high pitting corrosion resistant nonmagnetic, austenitic Cr-Ni-N-steel, specifically developed for oilfield applications.
|max. 0,03||1,50 - 3,00||26,50 - 29,50||2,00 - 4,00||min. 0,20||28,00 - 31,50|
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“||140 ksi||965 N/mm²|
|OD 9 1/2“ and larger||130 ksi||900 N/mm²|
|Tensile Strength (min.):||150 ksi||1035 N/mm²|
|Reduction of area (min.):||50%||50%|
|Impact energy (min.):||100 ft.lb||135 J|
|Endurance Strength / N=10⁵ (min.):||± 80 ksi||± 550 N/mm²|
|Hardness Brinell: (min.):||300-400 HB||300-400 HB|
3. MAGNETIC PROPERTIES
Relative permeability: ≤ 1,001.
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-, nickel- and nitrogen contents a excellent resistance to pitting corrosion comparable to nickelbase alloys 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.