ASTM A106 is the standard for high-temperature service seamless carbon steel pipes. ASTM A106 Grade B is the most widely used grade, featuring stable chemical properties, excellent high-temperature pressure resistance and reliable mechanical performance, suitable for long-term service under harsh high-temperature and high-pressure conditions.
It is commonly used in power plants, boiler systems, petrochemical plants, oil and gas refineries, as well as marine piping systems for conveying hot and cold liquid and gas media under high pressure and temperature.
1. ASTM A106 Grade B Chemical Composition
Strict chemical composition control ensures qualified weldability, high-temperature stability and mechanical properties. All values are mass percentages (%).
| Element |
Content Requirement (%) |
| Carbon (C) |
Max 0.30 |
| Manganese (Mn) |
0.29 - 1.06 |
| Phosphorus (P) |
Max 0.035 |
| Sulfur (S) |
Max 0.035 |
| Silicon (Si) |
Min 0.10 |
| Chromium (Cr) |
Max 0.40 |
| Copper (Cu) |
Max 0.40 |
| Molybdenum (Mo) |
Max 0.15 |
| Nickel (Ni) |
Max 0.40 |
| Vanadium (V) |
Max 0.08 |
2. ASTM A106 Grade B Testing Requirements
All A106 Grade B seamless pipes require mandatory batch sampling tests to ensure stable quality. Sampling quantities vary by pipe NPS size as follows:
| Test Item |
Pipe NPS Size |
Sampling Standard (One Length from Each Lot) |
| Tensile Test |
NPS 5 and smaller |
≤ 400 pieces/lot |
| Tensile Test |
NPS 6 and larger |
≤ 200 pieces/lot |
| Bending Test |
NPS 2 and smaller |
≤ 400 pieces/lot |
| Flattening Test |
NPS 2 - 5 |
≤ 400 pieces/lot |
| Flattening Test |
NPS 6 and over |
≤ 200 pieces/lot |
2.1 Hydrostatic Testing (Mandatory Inspection)
Hydrostatic test is an essential non-destructive test to verify pipe pressure resistance, complying with ASTM standard requirements:
Test Stress Standard: The inspection pressure generates a pipe wall stress equal to 60% of the room-temperature Specified Minimum Yield Strength (SMYS).
Maximum Test Pressure: NPS 3 and below: maximum 2500 psi; NPS larger than 3: maximum 2800 psi.
Pressure Holding Time: No less than 5 seconds to ensure no leakage or deformation of the pipe body.
3. A106 Grade B Equivalent Standards (Global Equivalent Materials)
ASTM A106 Grade B has internationally recognized equivalent grades with matching chemical composition, mechanical properties and high-temperature performance, which are interchangeable in most industrial projects. The equivalent standard comparison is listed below:
| Standard Region |
Equivalent Standard |
Equivalent Grade |
| Chinese GB Standard |
GB/T 8163 / GB/T 5310 |
20# Steel |
| European EN Standard |
EN 10216-2 |
P235GH |
| Japanese JIS Standard |
JIS G3454 |
STPG410 |
| American Standard |
ASTM A53 / API 5L |
Grade B |
| International ISO Standard |
ISO 630 |
E245 |
3.1 Equivalent Material Replacement Precautions
Though the above grades are equivalent to A106 Grade B, minor standard and tolerance differences exist. For critical high-temperature, high-pressure and long-service projects, confirm project specifications before material replacement to ensure safety and compliance.
4. Our Supply Capacity
We supply full-specification ASTM A106 Grade B seamless carbon steel pipes with complete certifications, stable quality and fast delivery. Custom processing and size customization are available. Contact us for detailed parameters, technical support and quotations.
