Seamless vs Welded Carbon Steel Pipe

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EN8 Chemical Composition

Seamless carbon steel pipes are known for their strength and durability due to the absence of joints, which reduces potential weak points. Their consistent mechanical properties along the entire length make them ideal for applications where reliability is critical. Additionally, they offer better resistance to high temperatures because there are no welds that could potentially weaken the structure.

The precise dimensions and thickness of seamless pipes ensure predictable performance in various environments, making them a preferred choice for demanding applications.

In contrast, welded carbon steel pipes may have reduced strength and durability compared to seamless ones. This is largely due to the welding process itself, which can cause changes in the microstructure and mechanical properties near the weld area, leading to lower toughness and resistance to stress.

Welded pipes might also exhibit surface imperfections such as weld beads or heat-affected zones, which often require additional finishing or cleaning to meet specific requirements.

Seamless carbon steel pipes are commonly used in:

  • High-pressure applications
  • Hydraulic systems
  • Critical liquid transport

Welded carbon steel pipes are typically used in:

  • Medium pressure and temperature applications
  • Non-corrosive fluid transport

Manufacturing Process

Seamless carbon steel pipes are produced by extruding a solid steel bar to create a hollow pipe, ensuring no joints or welds. This method results in a uniform design and structure.

Welded carbon steel pipes are manufactured by rolling a flat plate into a cylindrical shape and then welding it. Common methods include longitudinal (LSAW) and spiral (SSAW) welding.

Why Choose?

Seamless pipes are ideal for high-pressure environments where strength and reliability are crucial. They are often used in critical industries like oil and gas, chemical processing, and power generation.

Welded pipes are cost-effective and easier to manufacture, making them suitable for medium-pressure and temperature applications.

Table of contents

  • Carbon Steel seamless and welded pipe manufacturing process
  • Seamless vs Welded Carbon Steel Pipe Specification
  • Carbon steel Welded and seamless pipe equivalent
  • Tolerances for hot finished seamless pipe
  • Tolerances for cold drawn welded tubes
  • Carbon Steel seamless and welded pipes chemical composition
  • CS Welded and Seam Pipe mechanical properties
  • List of documents to import Low Temp Welded Pipe
  • A106 Seamless and Welded Pipe Schedule
  • CS Welded and Seamless Pipe International Standard
  • Hot finished welded type tubes sizes in mm
  • Difference between seamless pipe and erw pipe
  • Maximum Allowed Stress of DIN EN 10220 seamless steel pipes
  • Low Temp Seamless Pipe Charpy V-Notch Impact Tests
  • Hot Forming and Heat Treatment of CS ERW and Seamless pipe
  • List of machinery to produce seamless pipe
  • List of machinery to produce welded pipe
  • Testing for Seam pipe and ERW Pipe

List of Seamless Carbon Steel Pipe grades for high-temperature service, check uses and manufacturing process of CS SMLS and Welded pipes

Carbon Steel seamless and welded pipe manufacturing process

Carbon steel seamless pipe manufacturing process

Carbon steel seamless pipe manufacturing process

Carbon steel welded pipe manufacturing process

Carbon steel welded pipe manufacturing process

Check Carbon Steel welded and seamless pipe specifications, equivalent, tolerances, and properties

Seamless vs Welded Carbon Steel Pipe Specification

Size Range Wall thickness OD
  • Seamless Pipe: 1/2 to 36 ” NB
  • Welded Pipe : 6" to 48"
  • SCH10 – SCH160
  • 2mm to 45mm
 1/2” to 60”
High carbon steel seamless pipe sizes Indian standards Size
  • OD: 10.3- 610mm
  • Wall Thickness: 1.0-40mm
  • Longest length:12000mm
  • IS 1239
  • IS 3589
  • IS 4923
  • IS 3601
  • OD: 21.3-2540mm
  • Wall Thickness: 2.5-20mm
  • Longest length:12000mm
AMS standard Hardness range Maximum operating temperature
  • AMS 6360 (4130)
 767 HB  650°C (1202°F).
Expansion coefficient Joining methods Yield strength
12×10-6/°C
  • Live joint connection
  • Flange connection
  • Special pipe joint connection
 35,000 psi.
Plain carbon steel pipes form Estimated delivery time SWG
  • Coiled
  • Round
  • Straight
  • U Shape
  • Pan Cake Coils
  • Rectangular
  • Square
  • Hollow
  • Generally it is 7-10 days if its in stock
  • 15-20 days if its not in stock
  • Within 7 days to Saudi Arabia
  • 16 Swg.
  • 10 Swg.
  • 12 Swg.
  • 14 Swg.
  • 18 Swg.
  • 20 Swg.
Services Meet the requirements Length
  • Cut-to-length services
  • Machining
  • Threading
  • Welding
  • Beveling
  • ISO 15156
  • MTC EN 10204 3.1/ 3.2 certificate
  • NACE TM-0284
  • IBR
  • HIC tested
  • Sour service
  • NORSOK
  • NACE MR0103
  • NACE MR0175
  • Single
  • Double random
  • Cut length
  • Standard
  • 20FT
  • From 5 – 18 meters
  • DRL
  • SRL
  • 40FT
  • Custom / cut to size
Density Temperature range Melting point
7.85 g/cm3 to 8.05 g/cm3. 2200°F 1425-1540°C (2597-2800°F)
BS standards Black steel CS pipe classification Manufacturing technique
  • BS 3601
  • BS 1965-1
  • BS 1387
  • Low carbon steel: 0.05% – 0.25% carbon
  • Medium carbon steel: 0.25% – 0.5% carbon
  • High carbon steel: 0.5% – less than 2% carbon
  • Hot formed
  • Precision rolled
  • Cold formed
  • Cold drawn
Marking Applications Welding procedure
  • Schedule or wall thickness
  • Specification
  • Identification colour code
  • Material grade
  • Method of manufacturing (Seamless / Welded)
  • Heat number
  • Nominal size
  • Suppliers/ Manufacturers name or custom logo – as requested by buyer
  • Building foundations
  • Transporting wastewater
  • Transporting natural gases or oil
  • Chemical processing
  • Boiler and condenser tubes
  • Gas-shielded tungsten arc (TIG or GTAW)
  • Gas-shielded metal arc (MIG or GMAW)
  • Brazing
  • Tack welding
  • Manual metal arc (MMA or SMAW)
Weight calculator formula Features Certification
  •  Wt/Ft = 10.69*(OD – Wall Thickness)* Wall Thickness
  • Economical price for long diameter steel pipes
  • High hardness
  • Strength
  • Wear resistance
  • Anti-corrosion
  • DFARS compliant
  • MTC EN 10204 3.1, 3.2
  • Heat treatment charts
  • Surface roughness measurement
  • HS code commercial invoice
  • Fumigation certificates
  • Raw materials certificate
  • Third party inspection report
  • Moisture testing report
  • Laboratory test certificate from Govt. approved lab
  • Form a for generalized system of preferences (GSP)
Origin of material Standards Coatings
  • Korea
  • France
  • Italy
  • Europe
  • Japan
  • Indian (Quality Grade A/ B/ C in stock)
  • ASTM A53 B
  • ASTM A179
  • ASTM A135
  • ASTM A106 Gr. B
  • DIN 2440
  • API 5L Gr B to X70
  • ASTM A252
  • ASTM A134
  • ASTM A192
  • CSZ Z245
  • ASTM A333
  • NBR 8261
  • 3LPE/3PE coating
  • Varnished
  • Blacking painting
  • Zinc
  • Polyethylene layers
  • 3pp
  • FBE
  • Clad or Lined alloy steel
  • Soild CRA
Packaging Carbon steel pipe equipment Testing requirements
  • Crates (steel/wooden)
  • Wooden boxes
  • Wrapped in plastic or standard seaworthy export packing
  • Special crates for with each radius separated
  • Bundles (hexagonal)
  • PE fabric bundles
  • Electric bevelling machine
  • Sand-blasting machine
  • Bending machine
  • Pushing machine
  • Press machine
  • Geometric accuracy
  • Radiographic inspection
  • Liquid penetrant examination
  • Hydrotesting
  • And most important dimensional checking
  • Ultrasonic gaging

Carbon steel Welded and seamless pipe equivalent

DIN BS NFA ASTM
DIN 17175 Grade 17 Mn 4 NFAA 49-213 Grade TU 48-c ASTM A106 Grade C ASME SA 106 Grade C

Tolerances for hot finished seamless pipe

Outside Diameter Range
(inches)		 Wall Percent
of O.D.		 Unannealed or Stress
Relief Annealed		 Oil Quenched &
Tempered		 Soft Annealed or
Normalized
O.D. Inches I.D. Inches O.D. & I.D. O.D. Inches I.D. Inches
Plus Minus Plus Minus Plus/Minus Plus Minus Plus Minus
Up to 0.499 All 0.004 0.000 0.005 0.005 0.002
0.500-1.699 All 0.005 0.000 0.000 0.005 0.005 0.007 0.002 0.002 0.007
1.700-2.099 All 0.006 0.000 0.000 0.006 0.008 0.006 0.005 0.005 0.006
2.100-2.499 0.007 0.000 0.000 0.007 0.009 0.008 0.005 0.005 0.008
2.500-2.899 All 0.008 0.000 0.000 0.008 0.010 0.009 0.005 0.005 0.009
2.900-3.299 All 0.009 0.000 0.000 0.009 0.012 0.011 0.005 0.005 0.011
3.300-3.699 All 0.010 0.000 0.000 0.010 0.013 0.013 0.005 0.005 0.013
3.700-4.099 All 0.011 0.000 0.000 0.011 0.014 0.013 0.007 0.010 0.010
4.100-4.499 All 0.012 0.000 0.000 0.012 0.015 0.014 0.007 0.011 0.011
4.500-4.899 All 0.013 0.000 0.000 0.013 0.017 0.016 0.007 0.012 0.012
4.900-5.299 All 0.014 0.000 0.000 0.014 0.018 0.018 0.007 0.013 0.013
5.300-5.549 All 0.015 0.000 0.000 0.015 0.019 0.020 0.007 0.014 0.014
5.550-5.999 Under 6 0.010 0.010 0.010 0.010 0.025 0.018 0.018 0.018 0.018
6 to 7 1/2 0.009 0.009 0.009 0.009 0.023 0.016 0.016 0.016 0.016
Over 7 1/2 0.018 0.000 0.009 0.009 0.023 0.017 0.015 0.016 0.016

Tolerances for cold drawn welded tubes

Size Range
Inch (mm)		 OD Tolerance Inch (mm)
Over Under
Up to 2.999 (76.17) 0.020 (0.51) 0.020 (0.51)
3.000-4.499 (76.20-114.27) 0.025 (0.64) 0.025 (0.64)
4.500-5.999 (114.30-152.37) 0.031 (0.79) 0.031 (0.79)
6.000-7.499 (152.40-190.47) 0.037 (0.94) 0.037 (0.94)
7.500-8.999 (190.50-228.57) 0.045 (1.14) 0.045 (1.14)
9.000-10.750 (228.60-273.05) 0.050 (1.27) 0.050 (1.27)
10.750 and larger 1% 1%

Carbon Steel seamless and welded pipes chemical composition

ASTM A53

Values in % Type S
(Seamless)		 Type F
(Furnace Weld)		 Type E
(ERW)
A53 Grade A Grade B Grade A Grade A Grade B
Manganese 0.95 1.2 1.2 0.95 1.2
Carbon 0.25 0.3 0.3 0.25 0.3
Sulfur 0.045 0.045 0.045 0.045 0.045
Phosphorous 0.05 0.05 0.05 0.05 0.05
Nickel 0.4 0.4 0.4 0.4 0.4
Copper 0.4 0.4 0.4 0.4 0.4
Molybdenum 0.15 0.15 0.15 0.15 0.15
Chromium 0.4 0.4 0.4 0.4 0.4
Vanadium 0.08 0.08 0.08 0.08 0.08

ASTM A106

Element Mn C
max		 S
max		 P
max		 Cr
max (3)		 Si
min		 Mo
max (3)		 Cu
max (3)		 V
max (3)		 Ni
max (3)
Grade A 0.27-0.93 0.25 (1) 0.035 0.035 0.40 0.10 0.15 0.40 0.08 0.40
Grade B 0.29-1.06 0.30 (2) 0.035 0.035 0.40 0.10 0.15 0.40 0.08 0.40
Grade C 0.29-1.06 0.35 (2) 0.035 0.035 0.40 0.10 0.15 0.40 0.08 0.40

ASTM A333

Element Grade 3 Grade 6
C 0.19 0.30
Mn 0.31–0.64 0.29–1.06
P 0.025 0.025
S 0.025 0.025
Si 0.18–0.37 0.10 min
Ni 3.18–3.82 0.40
Cr … 0.30
Cu … 0.40
Al … …
V … 0.08
Cb … 0.02
Mo … 0.12
Co … …

CS Welded and Seam Pipe mechanical properties

ASTM A53

Seamless and ERW A53 Grade B A53 Grade A
Yield Strength 35,000 30,000
Tensile Strength, min, psi 60,000 48,000

ASTM A106

ASTM A106 Grade A Grade B Grade C
Yield Strength, min., psi 30,000 35,000 40,000
Tensile Strength, min., psi 48,000 60,000 70,000

ASTM A333

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ASTM A333 Yield Strength, min. Tensile Strength, min. Elongation %, min.
Grade psi MPa psi MPa Longitudinal Transverse
Grade 3 35 000 240 65 000 450 30 20
Grade 6 35 000 240