CARBON STEEL SEAMLESS PIPE
Carbon steel pipes are divided into hot rolled and cold rolled (pulled) steel pipes.
ANSI / API 5L specifies the manufacture of two product levels (PSL1 and PSL2) of seamless and welded steel pipe for the use of a pipeline in the transportation of petroleum and natural gas. For material use in a sour service application, refer to Annex H; for offshore service application, refer to Annex J of API 5L 45th Edition.
Ingots, blooms, billets, coils or plates used for the manufacture of pipe shall be made via basic oxygen, electric furnace or open hearth in combination with a ladle refining process. For PSL2, the steel shall be killed and melted according to a fine grain practice. Coil or plate used for PSL2 pipe shall not contain any repair welds.
API 5L steel line pipe adopts different steel grades, generally are Gr. B, X42, X46, X52, X56, X60, X65, X70, X80. Some manufacturers are capable of manufacturing steel grade up to X100 and X120. As the steel line pipe grades higher, more strictly control on the carbon equivalent control, and higher mechanical strength performances.
More over, for the same grade API 5L pipe, seamless and welded chemical elements content is different, which welded pipe is required more strictly and lower on Carbon and Sulfur.
By different delivery condition, there are also As-rolled, normalizing rolled, thermomechanical rolled, normalizing formed, normalized, normalized and tempered, quenched and tempered.
| Steel Grade | Mass fraction, % based on heat and product analyses a,g | ||||||
|---|---|---|---|---|---|---|---|
| C | Mn | P | S | V | Nb | Ti | |
| max b | max b | max | max | max | max | max | |
| Seamless Pipe | |||||||
| A | 0.22 | 0.9 | 0.3 | 0.3 | – | – | – |
| B | 0.28 | 1.2 | 0.3 | 0.3 | c,d | c,d | d |
| X42 | 0.28 | 1.3 | 0.3 | 0.3 | d | d | d |
| X46 | 0.28 | 1.4 | 0.3 | 0.3 | d | d | d |
| X52 | 0.28 | 1.4 | 0.3 | 0.3 | d | d | d |
| X56 | 0.28 | 1.4 | 0.3 | 0.3 | d | d | d |
| X60 | 0.28 e | 1.40 e | 0.3 | 0.3 | f | f | f |
| X65 | 0.28 e | 1.40 e | 0.3 | 0.3 | f | f | f |
| X70 | 0.28 e | 1.40 e | 0.3 | 0.3 | f | f | f |
| Welded Pipe | |||||||
| A | 0.22 | 0.9 | 0.3 | 0.3 | – | – | – |
| B | 0.26 | 1.2 | 0.3 | 0.3 | c,d | c,d | d |
| X42 | 0.26 | 1.3 | 0.3 | 0.3 | d | d | d |
| X46 | 0.26 | 1.4 | 0.3 | 0.3 | d | d | d |
| X52 | 0.26 | 1.4 | 0.3 | 0.3 | d | d | d |
| X56 | 0.26 | 1.4 | 0.3 | 0.3 | d | d | d |
| X60 | 0.26 e | 1.40 e | 0.3 | 0.3 | f | f | f |
| X65 | 0.26 e | 1.45 e | 0.3 | 0.3 | f | f | f |
| X70 | 0.26e | 1.65 e | 0.3 | 0.3 | f | f | f |
| a. Cu ≤ = 0.50% Ni; ≤ 0.50%; Cr ≤ 0.50%; and Mo ≤ 0.15%, b. For each reduction of 0.01% below the specified maximum concentration for carbon, an increase of 0.05% above the specified maximum concentration for Mn is permissible, up to a maximum of 1.65% for grades ≥ L245 or B, but ≤ L360 or X52; up to a maximum of 1.75% for grades > L360 or X52, but < L485 or X70; and up to a maximum of 2.00% for grade L485 or X70., c. Unless otherwise agreed NB + V ≤ 0.06%, d. Nb + V + TI ≤ 0.15%, e. Unless otherwise agreed., f. Unless otherwise agreed, NB + V = Ti ≤ 0.15%, g. No deliberate addition of B is permitted and the residual B ≤ 0.001% |
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| Steel Grade | Mass fraction, % based on heat and product analyses | Carbon Equiv a | |||||||||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| C | Si | Mn | P | S | V | Nb | Ti | Other | CE IIW | CE Pcm | |||||||||||
| max b | max | max b | max | max | max | max | max | max | max | ||||||||||||
| Seamless and Welded Pipe | |||||||||||||||||||||
| BR | 0.24 | 0.4 | 1.2 | 0.025 | 0.015 | c | c | 0.04 | e,l | 0.43 | 0.25 | ||||||||||
| X42R | 0.24 | 0.4 | 1.2 | 0.025 | 0.015 | 0.06 | 0.05 | 0.04 | e,l | 0.43 | 0.25 | ||||||||||
| BN | 0.24 | 0.4 | 1.2 | 0.025 | 0.015 | c | c | 0.04 | e,l | 0.43 | 0.25 | ||||||||||
| X42N | 0.24 | 0.4 | 1.2 | 0.025 | 0.015 | 0.06 | 0.05 | 0.04 | e,l | 0.43 | 0.25 | ||||||||||
| X46N | 0.24 | 0.4 | 1.4 | 0.025 | 0.015 | 0.07 | 0.05 | 0.04 | d,e,l | 0.43 | 0.25 | ||||||||||
| X52N | 0.24 | 0.45 | 1.4 | 0.025 | 0.015 | 0.1 | 0.05 | 0.04 | d,e,l | 0.43 | 0.25 | ||||||||||
| X56N | 0.24 | 0.45 | 1.4 | 0.025 | 0.015 | 0.10f | 0.05 | 0.04 | d,e,l | 0.43 | 0.25 | ||||||||||
| X60N | 0.24f | 0.45f | 1.40f | 0.025 | 0.015 | 0.10f | 0.05f | 0.04f | g,h,l | As agreed | |||||||||||
| BQ | 0.18 | 0.45 | 1.4 | 0.025 | 0.015 | 0.05 | 0.05 | 0.04 | e,l | 0.43 | 0.25 | ||||||||||
| X42Q | 0.18 | 0.45 | 1.4 | 0.025 | 0.015 | 0.05 | 0.05 | 0.04 | e,l | 0.43 | 0.25 | ||||||||||
| X46Q | 0.18 | 0.45 | 1.4 | 0.025 | 0.015 | 0.05 | 0.05 | 0.04 | e,l | 0.43 | 0.25 | ||||||||||
| X52Q | 0.18 | 0.45 | 1.5 | 0.025 | 0.015 | 0.05 | 0.05 | 0.04 | e,l | 0.43 | 0.25 | ||||||||||
| X56Q | 0.18 | 0.45f | 1.5 | 0.025 | 0.015 | 0.07 | 0.05 | 0.04 | e,l | 0.43 | 0.25 | ||||||||||
| X60Q | 0.18f | 0.45f | 1.70f | 0.025 | 0.015 | g | g | g | h,l | 0.43 | 0.25 | ||||||||||
| X65Q | 0.18f | 0.45f | 1.70f | 0.025 | 0.015 | g | g | g | h,l | 0.43 | 0.25 | ||||||||||
| X70Q | 0.18f | 0.45f | 1.80f | 0.025 | 0.015 | g | g | g | h,l | 0.43 | 0.25 | ||||||||||
| X80Q | 0.18f | 0.45f | 1.90f | 0.025 | 0.015 | g | g | g | i,j | As agreed | |||||||||||
| X90Q | 0.16f | 0.45f | 1.9 | 0.02 | 0.01 | g | g | g | j,k | As agreed | |||||||||||
| X100Q | 0.16f | 0.45f | 1.9 | 0.02 | 0.01 | g | g | g | j,k | As agreed | |||||||||||
| Welded Pipe | |||||||||||||||||||||
| BM | 0.22 | 0.45 | 1.2 | 0.025 | 0.015 | 0.05 | 0.05 | 0.04 | e,l | 0.43 | 0.25 | ||||||||||
| X42M | 0.22 | 0.45 | 1.3 | 0.025 | 0.015 | 0.05 | 0.05 | 0.04 | e,l | 0.43 | 0.25 | ||||||||||
| X46M | 0.22 | 0.45 | 1.3 | 0.025 | 0.015 | 0.05 | 0.05 | 0.04 | e,l | 0.43 | 0.25 | ||||||||||
| X52M | 0.22 | 0.45 | 1.4 | 0.025 | 0.015 | d | d | d | e,l | 0.43 | 0.25 | ||||||||||
| X56M | 0.22 | 0.45f | 1.4 | 0.025 | 0.015 | d | d | d | e,l | 0.43 | 0.25 | ||||||||||
| X60M | 0.12f | 0.45f | 1.60f | 0.025 | 0.015 | g | g | g | h,l | 0.43 | 0.25 | ||||||||||
| X65M | 0.12f | 0.45f | 1.60f | 0.025 | 0.015 | g | g | g | h,l | 0.43 | 0.25 | ||||||||||
| X70M | 0.12f | 0.45f | 1.70f | 0.025 | 0.015 | g | g | g | h,l | 0.43 | 0.25 | ||||||||||
| X80M | 0.12f | 0.45f | 1.85f | 0.025 | 0.015 | g | g | g | i,j | .043f | 0.25 | ||||||||||
| X90M | 0.1 | 0.55f | 2.10f | 0.02 | 0.01 | g | g | g | i,j | – | 0.25 | ||||||||||
| X100M | 0.1 | 0.55f | 2.10f | 0.02 | 0.01 | g | g | g | i,j | – | 0.25 | ||||||||||
| a. SMLS t>0.787”, CE limits shall be as agreed. The CEIIW limits applied fi C > 0.12% and the CEPcm limits apply if C ≤ 0.12%, b. For each reduction of 0.01% below the specified maximum for C, an increase of 0.05% above the specified maximum for Mn is permissible, up to a maximum of 1.65% for grades ≥ L245 or B, but ≤ L360 or X52; up to a maximum of 1.75% for grades > L360 or X52, but < L485 or X70; up to a maximum of 2.00% for grades ≥ L485 or X70, but ≤ L555 or X80; and up to a maximum of 2.20% for grades > L555 or X80., c. Unless otherwise agreed Nb = V ≤ 0.06%, d. Nb = V = Ti ≤ 0.15%, e. Unless otherwise agreed, Cu ≤ 0.50%; Ni ≤ 0.30% Cr ≤ 0.30% and Mo ≤ 0.15%, f. Unless otherwise agreed, g. Unless otherwise agreed, Nb + V + Ti ≤ 0.15%, h. Unless otherwise agreed, Cu ≤ 0.50% Ni ≤ 0.50% Cr ≤ 0.50% and MO ≤ 0.50%, i. Unless otherwise agreed, Cu ≤ 0.50% Ni ≤ 1.00% Cr ≤ 0.50% and MO ≤ 0.50%, j. B ≤ 0.004%, k. Unless otherwise agreed, Cu ≤ 0.50% Ni ≤ 1.00% Cr ≤ 0.55% and MO ≤ 0.80%, l. For all PSL 2 pipe grades except those grades with footnotes j noted, the following applies. Unless otherwise agreed no intentional addition of B is permitted and residual B ≤ 0.001%. |
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| Pipe Grade | Tensile Properties – Pipe Body of SMLS and Welded Pipes PSL 1 | Seam of Welded Pipe | ||
|---|---|---|---|---|
| Yield Strength a | Tensile Strength a | Elongation | Tensile Strength b | |
| Rt0,5 PSI Min | Rm PSI Min | (in 2in Af % min) | Rm PSI Min | |
| A | 30,500 | 48,600 | c | 48,600 |
| B | 35,500 | 60,200 | c | 60,200 |
| X42 | 42,100 | 60,200 | c | 60,200 |
| X46 | 46,400 | 63,100 | c | 63,100 |
| X52 | 52,200 | 66,700 | c | 66,700 |
| X56 | 56,600 | 71,100 | c | 71,100 |
| X60 | 60,200 | 75,400 | c | 75,400 |
| X65 | 65,300 | 77,500 | c | 77,500 |
| X70 | 70,300 | 82,700 | c | 82,700 |
| a. For intermediate grade, the difference between the specified minimum tensile strength and the specified minimum yield for the pipe body shall be as given for the next higher grade. | ||||
| b. For the intermediate grades, the specified minimum tensile strength for the weld seam shall be the same as determined for the body using foot note a. | ||||
| c. The specified minimum elongation, Af, expressed in percent and rounded to the nearest percent, shall be determined using the following equation: | ||||
 |
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| Where C is 1 940 for calculation using Si units and 625 000 for calculation using USC units | ||||
| Axc is the applicable tensile test piece cross-sectional area, expressed in square millimeters (square inches) , as follows | ||||
| – For circular cross-section test pieces, 130mm2 (0.20 in2) for 12.7 mm (0.500 in) and 8.9 mm (.350 in) diameter test pieces; and 65 mm2 (0.10 in2) for 6.4 mm (0.250in) diameter test pieces. | ||||
| – For full-section test pieces, the lesser of a) 485 mm2 (0.75 in2) and b) the cross-sectional area of the test piece, derived using the specified outside diameter and the specified wall thickness of the pipe, rounded to the nearest 10 mm2 (0.10in2) | ||||
| – For strip test pieces, the lesser of a) 485 mm2 (0.75 in2) and b) the cross-sectional area of the test piece, derived using the specified width of the test piece and the specified wall thickness of the pipe, rounded to the nearest 10 mm2 (0.10in2) | ||||
| U is the specified minimum tensile strength, expressed in megapascals (pounds per square inch) | ||||
| Pipe Grade | Tensile Properties – Pipe Body of SMLS and Welded Pipes PSL 2 | Seam of Welded Pipe | |||||
|---|---|---|---|---|---|---|---|
| Yield Strength a | Tensile Strength a | Ratio a,c | Elongation | Tensile Strength d | |||
| Rt0,5 PSI Min | Rm PSI Min | R10,5IRm | (in 2in) | Rm (psi) | |||
| Af % | |||||||
| Minimum | Maximum | Minimum | Maximum | Maximum | Minimum | Minimum | |
| BR, BN,BQ,BM | 35,500 | 65,300 | 60,200 | 95,000 | 0.93 | f | 60,200 |
| X42,X42R,X2Q,X42M | 42,100 | 71,800 | 60,200 | 95,000 | 0.93 | f | 60,200 |
| X46N,X46Q,X46M | 46,400 | 76,100 | 63,100 | 95,000 | 0.93 | f | 63,100 |
| X52N,X52Q,X52M | 52,200 | 76,900 | 66,700 | 110,200 | 0.93 | f | 66,700 |
| X56N,X56Q,X56M | 56,600 | 79,000 | 71,100 | 110,200 | 0.93 | f | 71,100 |
| X60N,X60Q,S60M | 60,200 | 81,900 | 75,400 | 110,200 | 0.93 | f | 75,400 |
| X65Q,X65M | 65,300 | 87,000 | 77,600 | 110,200 | 0.93 | f | 76,600 |
| X70Q,X65M | 70,300 | 92,100 | 82,700 | 110,200 | 0.93 | f | 82,700 |
| X80Q,X80M | 80,.500 | 102,300 | 90,600 | 119,700 | 0.93 | f | 90,600 |
| a. For intermediate grade, refer to the full API5L specification. | |||||||
| b. for grades > X90 refer to the full API5L specification. | |||||||
| c. This limit applies for pies with D> 12.750 in | |||||||
| d. For intermediate grades, the specified minimum tensile strength for the weld seam shall be the same value as was determined for the pipe body using foot a. | |||||||
| e. for pipe requiring longitudinal testing, the maximum yield strength shall be ≤ 71,800 psi | |||||||
| f. The specified minimum elongation, Af, expressed in percent and rounded to the nearest percent, shall be determined using the following equation: | |||||||
|
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| Where C is 1 940 for calculation using Si units and 625 000 for calculation using USC units | |||||||
| Axc is the applicable tensile test piece cross-sectional area, expressed in square millimeters (square inches) , as follows | |||||||
| – For circular cross-section test pieces, 130mm2 (0.20 in2) for 12.7 mm (0.500 in) and 8.9 mm (.350 in) diameter test pieces; and 65 mm2 (0.10 in2) for 6.4 mm (0.250in) diameter test pieces. | |||||||
| – For full-section test pieces, the lesser of a) 485 mm2 (0.75 in2) and b) the cross-sectional area of the test piece, derived using the specified outside diameter and the specified wall thickness of the pipe, rounded to the nearest 10 mm2 (0.10in2) | |||||||
| – For strip test pieces, the lesser of a) 485 mm2 (0.75 in2) and b) the cross-sectional area of the test piece, derived using the specified width of the test piece and the specified wall thickness of the pipe, rounded to the nearest 10 mm2 (0.10in2) | |||||||
| U is the specified minimum tensile strength, expressed in megapascals (pounds per square inch | |||||||
| g. Lower values fo R10,5IRm may be specified by agreement | |||||||
| h. for grades > x90 refer to the full API5L specification. | |||||||
Pipe to withstand a hydrostatic test without leakage through the weld seam or the pipe body. Jointers need not be hydrostatic tested provide the pipe sections used were successfully tested.
No cracks shall occur in any portion of the test piece and no opening of the weld shall occur.
Acceptance criteria for flattening test shall be:
Many PSL2 pipe sizes and grades require CVN. Seamless pipe is to be tested in the body. Welded pipe is to be tested in the body, pipe weld and heat-affected zone. Refer to the full API 5L specification for the chart of sizes and grades and required absorbed energy values.
