Selection summary
Overview
ASTM A106/A106M Grade B is a seamless carbon-steel pipe product specification for high-temperature service. It does not cover welded pipe, and the grade alone does not establish design pressure, allowable stress, corrosion allowance, low-temperature toughness, sour-service suitability, dimensions, ends or supplementary tests.
This page separates standard-oriented limits from typical reference data. Purchase acceptance comes from the ordered specification and certified material test report.
Names and systems
Identity & standards
Similar designations across ASTM, EN, JIS, and other systems are not automatically interchangeable. Product form and ordered standard control chemistry, properties, dimensions, condition, and testing.
Reference chemistry
Composition
| Element | Reference range | Why it matters |
|---|---|---|
| Carbon | Grade B maximum per current specification | Strength, weldability and graphitization context |
| Manganese | Specification-controlled | Strength and toughness support |
| Residual elements | Report and limits as required | Material control and code assessment |
Concise grade-family reference only. Confirm every element limit against the current standard for the exact product ordered.
Condition matters
Reference properties
Room-temperature product minimum; use code allowable stress for design.
Verify wall, test specimen and certified results.
Project and code can add stricter examination.
Environment first
Corrosion behavior
A106 Grade B has no inherent corrosion resistance; process chemistry controls allowance, coating, lining or upgrading.
Wet H2S, hydrogen, CO2 and under-deposit service require dedicated material controls.
Temperature, concentration, deposits, crevices, stress, surface finish, cleaning, and fabrication quality can change service performance.
Service limits
Temperature & service
Use the governing piping-code allowable stresses and temperature limits, not room-temperature handbook data.
Delivery condition
Heat treatment & condition
The seamless manufacturing and heat-treatment route must satisfy A106/A106M-26 and the ordered condition.
Project PWHT is a fabrication requirement and does not replace mill heat-treatment certification.
Process route
Fabrication
Pipe is intended to be suitable for bending, flanging and welding under qualified procedures.
Heavy wall, restraint, cold bending, local heating and PWHT require code-based procedure controls.
Magnetic response: Ferromagnetic.
Decision boundaries
Comparisons & substitution
A106 Grade B is seamless and high-temperature oriented; A53 Grade B covers different welded/seamless and coating options.
API 5L Grade B is ordered for line-pipe systems with PSL and pipeline-specific requirements.
Where it is used
Applications
Ordering scope
Product forms & standards
Seamless pipe in NPS/DN, wall or schedule, length and end configuration defined by the order.
Special dimensions and supplementary tests are accepted only when fully stated and compliant.
Decision support
Selection guidance
Choose this grade when
- The piping material specification calls for A106 Grade B seamless high-temperature pipe.
- Design code, pressure, temperature, medium and corrosion controls are known.
Review another grade when
- Welded construction, low-temperature toughness, severe sour service or line-pipe requirements govern.
- Alloy steel, stainless steel, cladding or another code-listed material is required by temperature or corrosion.
Before ordering
Procurement checklist
State A106/A106M-26 Grade B, seamless construction, NPS/DN, wall or schedule, length and ends.
State design code, pressure, temperature, medium, corrosion allowance, PWHT and supplementary tests.
Require MTR, traceability, test route, marking, NDE, packing and third-party witness points where needed.
Traceable evidence