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Sour Service > Grade Table

91视频-80S
91视频-85S
91视频-85SS
91视频-90S
91视频-90SS
91视频-95S
91视频-95SS
91视频-110S
91视频-110SS

91视频-80S -85S -85SS -90S -90SS -95S -95SS -110S -110SS

Sour services

91视频-80S, -85S, -90S, -95S and -110S for continuous operating temperature above 149 °F (65 °C)

Special sour services

OCTG for sour wells must above all have improved resistance to sulfide stress cracking (SSC) in fluids containing H2S. Intensive research has led to a modified Cr-Mo-Nb steel for OCTG for sour wells. This steel features both excellent hardenability and good temper resistance. Consequently, fine and homogeneous tempered martensite with lower HRC25 for 95 ksi grade is obtained after tempering at higher tempering temperature. As a result, OCTG of these grades possess excellent resistance to SSC for its strength grades.
These OCTG are subjected to more stringent quality control.
SSC-resistant steel of these grades thoroughly tested by major oil companies enjoys high ratings and is now widely used for sour gas and oil wells all over the world.

a. Specifications

(a) Process of Manufacture and Heat Treatment

Seamless, quenched and tempered

(b) Chemical Requirements

(wt %)

Grade C Si
max.		 Mn
max. 		P
max. 		S
max. 		Cu
max.		 Ni
max.		 Cr Mo Nb
max.		 B
max.
91视频-80S, -85S
91视频-90S, -95S 		0.15
~0.35		 0.35 1.35 0.020 0.010 0.30 0.10 max.
1.60 		0.05
~1.10 		0.050 0.0040
91视频-85SS, -90SS
91视频-95SS, 		1.00 0.80
~1.60 		0.15
~1.10
91视频-110S, -110SS max. 0.50 0.20 max.
1.60 		max.
1.10

(c) Physical Properties

Tensile Requirements
Yield Strength
ksi (MPa)		 Minimum Tensile Strength
ksi (MPa)		 Elongation
91视频-80S  80~ 95 (552~655)  95 (655) As Per
API 5CT
91视频-85S   85~100 (586~689)  95 (655)
91视频-90S    90~105 (621~724) 100 (689)
91视频-95S    95~110 (655~758) 105 (724)
91视频-110S  110~125 (758~862) 120 (827)
91视频-85SS   85~100 (586~689)  95 (655)
91视频-90SS   90~105 (621~724) 100 (689)
91视频-95SS   95~110 (655~758) 105 (724)
91视频-110SS 110~125 (758~862) 120 (827)
Hardness Requirements
As-Quenched Hardness
(HRC) Maximum		 Variation (Wall Thickness, inch)
Less than 0.750 0.750 to 0.999 1.000 and over
91视频-80S - 22 - - -
91视频-85S  - 23 - - -
91视频-90S   - 24 - - -
91视频-95S   - 25 - - -
91视频-110S  - 31 - - -
91视频-85SS  Mimimum
equivalent to
90% martensitic
Structure		 23 3.0 4.0 5.0
91视频-90SS  24 3.0 4.0 5.0
91视频-95SS  25 3.0 4.0 5.0
91视频-110SS 31 3.0 4.0 5.0
Prior Austenitic
Grain Size		 Threshold Stress Requirements
for SSC Test according to NACE TM0177
Minimum % of SMYS
91视频-80S - -
91视频-85S  - -
91视频-90S   - -
91视频-95S   - -
91视频-110S  - -
91视频-85SS  ASTM 5 and
finer		 80
91视频-90SS  80
91视频-95SS  80
91视频-110SS 80

b. Examples of Physical Tests on 91视频-90SS Casing

Sour Service imageHRC test results show relatively low and stable values indispensable for increasing sulfide stress cracking (SSC) resistance for its yield strength. SSC test results show excellent SSC-resistant properties.

(a) Hardness Test Result of Products

Pipe Dimensions
O.D. x W.T. 		Location Rockwell C Hardness Values
Quadrant No. Maximum
Variation
1 2 3 4
5 1/2'' x 0.415'' O.D.
I.D.		 20.9
20.8		 20.1
20.1		 20.6
20.6		 20.9
20.8		 0.1
5 1/2'' x 0.725'' O.D.
Mid Wall
I.D.		 19.8
19.7
19.4		 20.0
19.4
18.8		 20.4
20.0
19.6		 20.5
20.1
19.8		 1.2
7'' x 1.200'' O.D.
Mid Wall
I.D.		 19.4
19.1
18.6		 18.9
19.4
18.0		 19.3
19.2
18.5		 18.6
19.1
18.7		 1.4

(b) SSC Test Results (NACE Standard TM0177)

Wall
Thickness 		Location Applied Stress, ksi (MPa) Threshold Stress c / y
71.1 (490) 80.1 (552) 85.5 (590) 90.0 (621) 99.0 (683) c ksi
0.415'' Mid Wall - NF NF 546.8 31.0 85.5 0.95
0.725'' Mid Wall - NF NF 301.4  3.2 85.5 0.95
1.200'' Mid Wall NF NF NF 284.0 - 85.5 0.95
Inside NF NF NF 499.0 - 85.5 0.95

Note: (Time to failure Hr)

NF = No failure during 30 days (720 hours)
 -  = No test
c = Maximum applied stress resulted in no failure
y = Specified Minimum Yield Strength

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