P750

1. CHEMICAL COMPOSITION

„P750 “ is a high pitting corrosion resistant nonmagnetic, austenitic Cr-Ni-N-steel, specifically developed for oilfield applications.

C Mn Cr Mo N Ni
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:

TEXT OD KSI N/MM
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
Elongation (min.):   17% 17%
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.