ASTM A106 Grade C is a premium seamless carbon steel pipe engineered for extreme high-temperature and high-pressure industrial service. As the highest-strength grade in the ASTM A106 series, it boasts upgraded tensile and yield strength compared to Grade B, delivering exceptional structural rigidity and pressure resistance for the most demanding industrial operating conditions.
Built with a fully seamless weld-free structure, A106 Grade C eliminates weld defects and structural stress concentration points. It features stable chemical composition and outstanding thermal fatigue resistance, supporting long-term, continuous operation under harsh working conditions. This grade is widely specified for power plants, industrial boilers, petrochemical refineries, oil and gas facilities, and marine piping systems, for transporting high and low-temperature liquid and gas media under extreme pressure.
Product Specifications
We offer a complete size range of ASTM A106 Grade C seamless carbon steel pipes with sufficient in-stock inventory for fast lead times. Custom dimensions and professional secondary processing services are available to meet strict technical requirements for extreme-condition industrial projects.
| Item |
Specification Details |
| Steel Grade |
ASTM A106 Grade C |
| Executive Standard |
ASTM A106 / A106M Standard |
| Pipe Type |
Seamless Carbon Steel Pipe (Weld-Free Structure) |
| Outer Diameter |
1/8" – 24", support custom outer diameter |
| Wall Thickness |
SCH20 / SCH40 / SCH80 / SCH160, customizable thickness as required |
| Core Advantage |
Ultra-high mechanical strength, superior high-pressure & high-temperature resistance, excellent structural stability |
| Applicable Scenario |
Extreme high-temperature & high-pressure industrial piping, critical boiler, petrochemical and marine systems |
| Surface Condition |
Smooth inner & outer surface, uniform wall thickness, no defects |
| MOQ |
1 Ton / Negotiable |
| Delivery Time |
3–7 days (stock); 15–30 days (custom) |
| Custom Service |
Custom size, cutting, threading, bending and precision processing |
| Certification |
MTC / EN 10204 3.1 / Third-party inspection available |
| Payment Terms |
T/T, L/C, Western Union, Trade Assurance |
Chemical Composition (Mass %)
ASTM A106 Grade C adopts a high-strength optimized carbon steel formulation with a higher maximum carbon content and tightly controlled trace elements. This precision chemical design delivers enhanced mechanical strength and superior structural stability at high temperatures, fully complying with stringent global standards for extreme industrial service applications.
| Element |
Content Requirement (%) |
| C (Carbon) |
Max 0.35 |
| Mn (Manganese) |
0.29 – 1.06 |
| P (Phosphorus) |
Max 0.035 |
| S (Sulfur) |
Max 0.035 |
| Si (Silicon) |
Min 0.10 |
| Cr (Chromium) |
Max 0.40 |
| Cu (Copper) |
Max 0.40 |
| Mo (Molybdenum) |
Max 0.15 |
| Ni (Nickel) |
Max 0.40 |
| V (Vanadium) |
Max 0.08 |
Mechanical Properties
ASTM A106 Grade C achieves the maximum mechanical performance across the entire A106 product series. Its upgraded yield and tensile strength deliver excellent rigidity and anti-deformation capability, maintaining stable structural integrity during long-cycle high-temperature and high-pressure operation.
| Mechanical Index |
Standard Value |
| Minimum Yield Strength |
275 MPa (40,000 psi) |
| Tensile Strength |
≥ 485 MPa (70,000 psi Min) |
| Minimum Elongation (50mm Gauge Length) |
20% |
Standard Testing & Inspection Requirements
All ASTM A106 Grade C seamless pipes undergo strict batch sampling tests and mandatory non-destructive inspections in full compliance with ASTM standard specifications. Full-process quality control ensures consistent mechanical performance and reliable adaptability to extreme working conditions.
Batch Sampling Test Standard
| Test Item |
Pipe NPS Size |
Sampling Standard |
| Tensile Test |
NPS 5 and smaller |
1 piece per ≤400 pieces/lot |
| Tensile Test |
NPS 6 and larger |
1 piece per ≤200 pieces/lot |
| Bending Test |
NPS 2 and smaller |
1 piece per ≤400 pieces/lot |
| Flattening Test |
NPS 2 – 5 |
1 piece per ≤400 pieces/lot |
| Flattening Test |
NPS 6 and over |
1 piece per ≤200 pieces/lot |
Mandatory Hydrostatic Testing
Hydrostatic testing is a compulsory non-destructive inspection to verify pipe pressure tightness and structural stability. It is implemented on every finished pipe to guarantee safe, leak-free and stable operation under extreme high-pressure and high-temperature working environments:
Test Stress Standard: The inspection pressure generates pipe wall stress equal to 60% of room-temperature Specified Minimum Yield Strength (SMYS).
Maximum Test Pressure: NPS 3 and below: max 2500 psi; NPS larger than 3: max 2800 psi.
Pressure Holding Time: Minimum 5 seconds to ensure no leakage, no deformation and intact pipe structure.
Product Features & Advantages
ASTM A106 Grade C is the high-strength upgraded grade of the standard A106 seamless pipe series. Compared with Grade B, it features higher tensile & yield strength, stronger pressure-bearing capacity and better structural rigidity. The weld-free seamless structure eliminates potential defects and stress concentration. It delivers excellent dimensional stability and thermal deformation resistance during long-term extreme service, with superior fatigue resistance and extended service life. It is the optimal material for critical industrial projects with stringent mechanical and temperature resistance requirements.
Application Fields
Benefiting from ultra-high mechanical strength and excellent high-temperature & high-pressure resistance, ASTM A106 Grade C seamless pipes are widely applied in high-standard industrial scenarios that require extreme environmental adaptability and long-term operational stability.
| Application Field |
Typical Usage & Components |
| Power Generation Industry |
High-pressure boiler piping, ultra-high temperature steam transmission pipelines, critical thermal power auxiliary systems |
| Petrochemical & Refinery Industry |
Oil & gas refinery high-pressure piping, high-temperature reaction equipment connecting pipelines, heavy-duty chemical medium transmission systems |
| Marine Engineering |
Marine extreme-condition high-pressure piping, ship heavy-load thermal medium conveying systems |
| High-Pressure Process Industry |
Industrial high-pressure process piping, extreme temperature circulation pipelines and heavy-duty pressure fluid transmission systems |
We supply high-quality ASTM A106 Grade C seamless carbon steel pipes with full specifications, complete certification documents and strict factory quality testing. Custom sizing, cutting, threading, bending and other deep processing services are available. Feel free to contact us for professional technical guidance and competitive wholesale quotes!
