ASTM A106 Grade C
Carbon Steel ASTM A106 Grade C
ASTM A106 Grade C Carbon Steel is a seamless carbon steel pipe grade primarily used for high-temperature and high-pressure service.
ASTM A106/A106M covers seamless carbon steel pipe intended for elevated-temperature service. Grade C has the highest minimum tensile and yield strength among ASTM A106 Grades A, B, and C.
With its combination of high mechanical strength, ductility, weldability, fabrication capability, and elevated-temperature performance, ASTM A106 Grade C can be considered for demanding industrial piping applications.
It is used in oil & gas, refineries, petrochemical plants, power generation, steam systems, process plants, and industrial piping where the specified design conditions require its mechanical properties.
Key Features
- Carbon steel for elevated-temperature service
- Seamless steel pipe
- High tensile strength
- High yield strength
- Good ductility
- Good weldability
- Good bendability
- Good machinability
- Suitable for pressure piping
- Suitable for process piping
- Available in various pipe sizes and wall thicknesses
- Suitable for demanding industrial applications
Specifications
| Specification | Details |
|---|---|
| Grade | ASTM A106 Grade C |
| Material | Carbon Steel |
| Standard | ASTM A106/A106M |
| Product | Seamless Carbon Steel Pipe |
| Manufacturing | Seamless |
| Grades | A, B, C |
| Service | High Temperature & Pressure |
| Ends | Plain or Beveled |
| Weldability | Good |
| Mechanical Strength | High |
| Main Applications | Oil & Gas, Refinery, Power, Petrochemical, Process |
Types of ASTM A106 Grade C Pipe
ASTM A106 Grade C is supplied as seamless carbon steel pipe.
ASTM A106 Grade C Seamless Pipe
The pipe is manufactured without a longitudinal welded seam, making it suitable for applications where pressure, temperature, and mechanical integrity are important considerations.
Common End Configurations
- Plain End
- Beveled End
- Threaded End for selected applications
Beveled ends are commonly used for butt-welding during piping installation.
Equivalent Grades
| Standard | Grade / Comparable Material |
|---|---|
| ASTM | A106 Grade C |
| EN | To be determined according to application |
| DIN | To be determined according to product |
| JIS | To be determined according to project requirements |
There is not necessarily a direct equivalent in every international standard. Any material substitution should be evaluated based on chemical composition, mechanical properties, pressure, temperature, design code, and project requirements.
Available Sizes
ASTM A106 Grade C seamless pipe is available in a wide range of nominal diameters and wall thicknesses.
Common Pipe Schedules
- SCH 10
- SCH 20
- SCH 30
- SCH 40
- SCH 60
- SCH 80
- SCH 100
- SCH 120
- SCH 140
- SCH 160
- XXS
Product Forms
- Seamless Pipe
- Plain-End Pipe
- Beveled-End Pipe
- Threaded Pipe for suitable applications
Exact dimensions depend on the nominal pipe diameter, wall thickness, length, manufacturing requirements, and project specifications.
ASTM A106 Grade C Chemical Composition
| Element | Content (%) |
|---|---|
| Carbon (C) | ≤ 0.35 |
| Manganese (Mn) | 0.29–1.06* |
| Phosphorus (P) | ≤ 0.035 |
| Sulfur (S) | ≤ 0.035 |
| Silicon (Si) | ≥ 0.10 |
| Chromium (Cr) | ≤ 0.40 |
| Nickel (Ni) | ≤ 0.40 |
| Molybdenum (Mo) | ≤ 0.15 |
| Copper (Cu) | ≤ 0.40 |
| Vanadium (V) | ≤ 0.08 |
| Iron (Fe) | Balance |
*Chemical requirements should be verified against the applicable edition of ASTM A106/A106M and the product’s material test certificate.
ASTM A106 Grade C Mechanical Properties
| Property | Minimum Value |
|---|---|
| Tensile Strength | 485 MPa |
| Yield Strength | 275 MPa |
| Elongation | According to pipe diameter and wall thickness |
| Hardness | According to applicable requirements |
ASTM A106 Grade C provides the highest minimum mechanical strength among Grades A, B, and C of the ASTM A106 specification.
ASTM A106 Grade C Physical Properties
| Property | Approximate Value |
|---|---|
| Density | 7.85 g/cm³ |
| Modulus of Elasticity | ≈ 200 GPa |
| Thermal Conductivity | ≈ 45–55 W/m·K |
| Thermal Expansion Coefficient | ≈ 11–12 × 10⁻⁶ /°C |
| Specific Heat Capacity | ≈ 480 J/kg·K |
| Magnetic Properties | Magnetic |
Corrosion Resistance
ASTM A106 Grade C is a carbon steel and therefore has limited inherent corrosion resistance compared with stainless steel.
It can be susceptible to:
- Atmospheric corrosion
- Moisture
- Water
- Chlorides
- Marine environments
- Certain chemicals
- Internal corrosion depending on the transported fluid
Corrosion Protection
Depending on the operating environment, protection may include:
- Industrial painting
- Epoxy coating
- Internal pipe coating
- Cathodic protection
- Corrosion inhibitors where applicable
For highly corrosive services, stainless steel, alloy steel, or specially protected carbon steel may be more appropriate.
Heat Resistance
ASTM A106 Grade C is intended for applications requiring good mechanical performance at elevated temperatures.
It may be considered for systems transporting:
- Steam
- Hot water
- Hot hydrocarbons
- Process fluids
- High-temperature gases
However, mechanical properties decrease as temperature increases. Therefore, allowable pressure and temperature must be established according to the applicable design code and actual operating conditions.
Heat Treatment
Heat treatment requirements depend on the manufacturing process and the requirements of ASTM A106/A106M.
Normalizing
Normalizing may be used to obtain a more uniform microstructure and balanced mechanical properties.
Stress Relieving
Stress relieving may be applied after certain fabrication or welding operations to reduce residual stresses.
Post-Weld Heat Treatment
Where PWHT is required, it should be performed according to the applicable design code and qualified welding procedure.
Welding
ASTM A106 Grade C can be welded using conventional welding processes. Due to its higher carbon content compared with Grades A and B, welding procedures should be appropriately qualified.
Common Welding Processes
- SMAW
- GTAW / TIG
- GMAW / MIG
- FCAW
- SAW
Welding Applications
- Butt welding
- Fitting connections
- Flange welding
- Branch connections
- Pipe spool fabrication
- Process piping assemblies
For certain wall thicknesses and service conditions, preheating, interpass temperature control, and PWHT may be required.
Fabrication
ASTM A106 Grade C can be processed using conventional pipe fabrication techniques.
Cutting
- Mechanical sawing
- Plasma cutting
- Oxy-fuel cutting
- Abrasive cutting
Bending
Pipe bending can be performed according to the required radius and applicable fabrication requirements.
Machining
- Drilling
- Turning
- Milling
- Threading
- Tapping
End Preparation
- Plain ends
- Beveled ends
- Welding-end preparation
Applications
Oil & Gas Industry
- Process piping
- Pressure lines
- Steam lines
- Hot hydrocarbon lines
- Auxiliary piping
Refineries
- Process piping
- Steam systems
- Hydrocarbon lines
- Hot-fluid lines
- Heating systems
Petrochemical Industry
- Process piping
- High-pressure piping
- Steam networks
- Hot process-fluid systems
Power Generation
- Steam piping
- Thermal systems
- Hot-water systems
- Auxiliary piping
- Process piping
General Industry
- Industrial piping
- Pressure systems
- Thermal installations
- Hot-fluid transportation
- Industrial process systems
ASTM A106 Grade C in Tunisia, Algeria, Morocco & Libya
Carbon Steel ASTM A106 Grade C can be considered for industrial projects across Tunisia, Algeria, Morocco, and Libya, particularly in oil & gas, refineries, petrochemical plants, power generation, steam systems, and process industries.
Its higher minimum mechanical strength compared with Grades A and B makes it suitable for selected applications where increased mechanical performance is required.
Material selection should always consider operating pressure, temperature, fluid characteristics, pipe wall thickness, applicable design code, and project specifications.
For North African projects, ASTM A106 Grade C may be evaluated alongside ASTM A106 Grade A, ASTM A106 Grade B, ASTM A53 Grade B, and API 5L, depending on the application.
ASTM A106 Grade A vs Grade B vs Grade C
| Property | Grade A | Grade B | Grade C |
|---|---|---|---|
| Material | Carbon Steel | Carbon Steel | Carbon Steel |
| Manufacturing | Seamless | Seamless | Seamless |
| Tensile Strength | ≥ 330 MPa | ≥ 415 MPa | ≥ 485 MPa |
| Yield Strength | ≥ 205 MPa | ≥ 240 MPa | ≥ 275 MPa |
| High-Temperature Service | Yes | Yes | Yes |
| Mechanical Strength | Good | High | Very High |
| Typical Application | General process service | Industrial process piping | More mechanically demanding applications |
Conclusion
Carbon Steel ASTM A106 Grade C is a high-strength seamless carbon steel pipe grade for high-temperature and pressure service.
With a minimum tensile strength of 485 MPa and yield strength of 275 MPa, it provides the highest minimum mechanical strength among ASTM A106 Grades A, B, and C.
It can be used in refineries, petrochemical plants, power generation facilities, oil & gas projects, steam systems, thermal processes, and industrial process piping where its properties are appropriate for the design conditions.
For projects in Tunisia, Algeria, Morocco, and Libya, ASTM A106 Grade C can provide a suitable solution for demanding seamless piping applications when the pressure, temperature, fluid, dimensions, and applicable design code comply with ASTM A106/A106M.
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