ASTM A312 TP310S Stainless Steel Pipe Tube Heat Resistant SS Pipe
Alloy 1.4845 SCH40S
ASTM A312 TP310S stainless steel pipe (also designated as Alloy
1.4845 and commonly supplied in SCH40S wall thickness) is a premium
heat-resistant austenitic stainless steel product engineered for
high-temperature and corrosive industrial environments. Its unique
chemical composition and mechanical properties make it a preferred
choice for applications requiring long-term stability under extreme
thermal stress. Below is a comprehensive overview of its
parameters, standards, specifications, features, equivalent grades,
and typical applications.
1. Core Chemical Composition (Weight %)
The chemical makeup of TP310S is strictly regulated to ensure heat
resistance and corrosion performance, as defined by ASTM standards:
| Element | Minimum (%) | Maximum (%) | Key Function |
|---|
| Carbon (C) | - | 0.08 | Reduces carbide precipitation at high temperatures, preventing
intergranular corrosion |
| Chromium (Cr) | 24.0 | 26.0 | Forms a dense oxide layer (Cr₂O₃) for oxidation resistance at
temperatures up to 1150°C (2102°F) |
| Nickel (Ni) | 19.0 | 22.0 | Stabilizes the austenitic structure, enhancing ductility and
resistance to thermal fatigue |
| Manganese (Mn) | - | 2.0 | Improves workability without compromising heat resistance |
| Silicon (Si) | - | 1.5 | Aids in oxide layer formation and enhances high-temperature
strength |
| Phosphorus (P) | - | 0.045 | Controlled to minimize brittleness and maintain weldability |
| Sulfur (S) | - | 0.030 | Reduced to prevent hot cracking during fabrication |
| Iron (Fe) | Balance | - | Base metal providing structural integrity |
2. Compliance Standard: ASTM A312
This pipe strictly adheres to ASTM A312, a widely recognized
American standard for seamless and welded austenitic stainless
steel pipes intended for high-pressure and high-temperature
service. Key requirements of ASTM A312 include:
- Uniform chemical composition across the pipe length.
- Rigorous mechanical property testing (tensile, elongation).
- Non-destructive testing (NDT) options: Hydrostatic testing
(mandatory) to verify leak tightness; optional ultrasonic testing
(UT) or eddy current testing (ECT) for defect detection.
- Weld quality control (for welded pipes) to ensure no
internal/external cracks or porosity.
3. Physical & Mechanical Properties
TP310S exhibits excellent mechanical stability at both ambient and
elevated temperatures:
| Property | Specification | Test Condition |
|---|
| Density | 8.0 g/cm³ | Ambient temperature |
| Melting Point | 1400–1450°C (2552–2642°F) | - |
| Tensile Strength (Minimum) | 515 MPa (74,700 psi) | Room temperature |
| Yield Strength (0.2% Offset, Minimum) | 205 MPa (29,700 psi) | Room temperature |
| Elongation (Minimum) | 35% | Room temperature (50 mm gauge length) |
| Thermal Conductivity | 14.2 W/(m·K) | At 100°C (212°F) |
| Coefficient of Thermal Expansion | 16.0 × 10⁻⁶/°C | 20–100°C (68–212°F) |
| Maximum Service Temperature | 1150°C (2102°F) | Continuous use (oxidizing environments) |
4. Product Specifications (SCH40S & Dimensions)
The "SCH40S" designation refers to the standard wall thickness for
stainless steel pipes, designed to balance pressure resistance and
weight efficiency. Common dimensional ranges for ASTM A312 TP310S
SCH40S pipes include:
| Parameter | Range | Notes |
|---|
| Outer Diameter (OD) | 1/2" – 24" (12.7 mm – 609.6 mm) | Complies with ANSI/ASME B36.19 (stainless steel pipe dimensions) |
| Wall Thickness (SCH40S) | 3.91 mm (for 2" OD) – 11.91 mm (for 10" OD) | Thickness varies with OD; exact values follow B36.19 |
| Length | 6 meters (20 ft) – 12 meters (40 ft) | Standard mill lengths; custom lengths available on request |
| Form | Seamless or Welded (ERW/SAW) | Seamless pipes for high-pressure applications; welded for
lower-pressure, large-diameter needs |
| Surface Finish | 2B (cold-rolled, smooth), No. 4 (brushed), or Pickled & Passivated | Pickled finish is common for corrosion resistance; 2B for sanitary
or aesthetic applications |
5. Key Features
TP310S stainless steel pipe stands out for its combination of heat
resistance, corrosion performance, and workability:
- Exceptional Heat Resistance: Sustains structural integrity in
continuous service up to 1150°C (2102°F) and intermittent service
up to 1200°C (2192°F), making it far more heat-tolerant than common
grades like 304 or 316.
- Superior Corrosion Resistance: Resists oxidation, sulfidation, and
carburization in high-temperature environments (e.g., furnace flue
gases, steam). Also offers good resistance to mild acids (e.g.,
dilute sulfuric acid) and saltwater.
- Excellent Ductility & Weldability: Can be easily welded using
standard methods (TIG, MIG, SMAW) without losing mechanical
properties. Its high elongation rate (≥35%) enables bending,
forming, and fabrication into complex shapes.
- Low Carbon Content: The 0.08% max carbon limits carbide
precipitation at grain boundaries (a common cause of cracking in
high-temperature service), ensuring long-term reliability.
6. Equivalent Grades
TP310S is known by different designations globally, depending on
regional standards. Below is a list of key equivalent grades for
cross-reference:
| Standard | Grade Designation | Region |
|---|
| ASTM/ASME | TP310S | North America |
| EN 10216-5 | 1.4845 | Europe |
| JIS G3463 | SUS310S | Japan |
| GB/T 14976 | 06Cr25Ni20 | China |
| UNS | S31008 | International (Unified Numbering System) |
Note: While these grades are chemically and mechanically similar,
minor variations may exist in 微量元素 (trace elements) or testing
requirements. Always confirm compatibility with specific
application standards.
7. Typical Applications
Due to its heat resistance and corrosion performance, ASTM A312
TP310S SCH40S pipe is widely used in high-temperature industrial
sectors:
- Heat Treatment Equipment: Furnace tubes, radiant tubes, and heating
elements for industrial furnaces (e.g., annealing, hardening
furnaces).
- Power Generation: Boiler tubes, superheater tubes, and steam
pipelines in coal-fired, gas-fired, or waste-to-energy power
plants.
- Petrochemical & Refining: Pipes for catalytic crackers, reformers,
and exhaust systems (resists sulfidation from crude oil
processing).
- Metallurgical Industry: Pipes for steel mill exhausts, molten metal
transfer lines, and sintering plants.
- Other High-Temperature Uses: Incinerator chimneys, thermal
oxidizers, and food processing equipment (where heat and corrosion
resistance are critical).
ASTM A312 309S SS Pipe DIN 1.4833 Seamless Stainless Steel Round Pipe
