The 8-inch ASTM A312 TP316 stainless steel pipe SCH 80 is a high-quality austenitic stainless steel pipe designed for corrosive and high-pressure industrial applications, especially in oil & gas pipelines. Manufactured according to ASTM International ASTM A312 specification, TP316 offers excellent resistance to chloride corrosion, pitting, and crevice attack, making it ideal for offshore, petrochemical, and high-salinity environments.
Schedule 80 (SCH 80) indicates a thicker wall, suitable for medium to high-pressure pipelines, ensuring durability and long-term operational safety.
Standard & Material Overview
Specification: ASTM A312 / A312M
Grade: TP316 (UNS S31600)
Schedule: SCH 80
Nominal Pipe Size: 8 inch (NPS 8)
Dimension Standard: ASME B36.19M
Manufacturing Type: Seamless (SMLS) / Welded (ERW / EFW)
Inspection Certificates: EN 10204 3.1 / 3.2 available
TP316 contains molybdenum, which enhances corrosion resistance in chloride-rich environments typical of oil & gas pipelines.
8" SCH 80 Pipe Dimensions & Weight
| NPS | OD (mm/inch) | Wall Thickness SCH 80 | Inside Diameter (Approx.) | Weight per Meter | Weight per Foot |
|---|---|---|---|---|---|
| 8" | 219.08 mm (8.625") | 10.97 mm (0.432") | 197.14 mm | 61.0 kg/m | 40.9 lb/ft |
Notes:
Dimensions follow ASME B36.19M
Weight is approximate for seamless pipes; welded pipes may differ slightly
Chemical Composition of TP316
| Element | Composition (%) |
|---|---|
| C | ≤ 0.08 |
| Cr | 16.0 – 18.0 |
| Ni | 10.0 – 14.0 |
| Mo | 2.0 – 3.0 |
| Mn | ≤ 2.0 |
| Si | ≤ 1.0 |
| P | ≤ 0.045 |
| S | ≤ 0.030 |
Molybdenum addition provides superior resistance against pitting and crevice corrosion in high-salinity oil & gas environments.
Mechanical Properties (Minimum)
| Property | Value |
|---|---|
| Tensile Strength | ≥ 485 MPa |
| Yield Strength | ≥ 170 MPa |
| Elongation | ≥ 35% |
| Hardness | ≤ 95 HRB |
TP316 maintains mechanical integrity under high-pressure and temperature conditions typical in pipelines.
Why Choose SCH 80 for Oil & Gas Pipelines?
Provides higher allowable working pressure than SCH 40
Ensures increased safety margin in critical pipeline applications
Suitable for offshore and high-pressure process lines
Balances durability and cost-effectiveness
Typical Applications
🛢 Oil & Gas Industry
High-pressure crude oil and gas pipelines
Offshore and onshore process lines
Chemical injection pipelines
🏭 Petrochemical Industry
Corrosive chemical transfer
Saltwater handling pipelines
⚡ Power & Industrial Plants
High-temperature water or steam lines
Cooling water pipelines
🌍 Marine & Seawater Systems
Seawater cooling pipelines
Desalination plant pipelines
Seamless vs Welded TP316 Pipe
| Type | Recommended Use |
|---|---|
| Seamless | High-pressure, critical pipeline sections |
| Welded | General piping for lower-pressure service |
| EFW | Large-diameter pipelines, usually >12" |
For an 8" SCH 80 pipeline in oil & gas, seamless pipe is often preferred for better mechanical performance.
Inspection & Quality Control
Chemical composition analysis
Tensile and hardness testing
Hydrostatic testing
Ultrasonic testing (UT)
Radiographic testing (RT)
PMI (Positive Material Identification)
EN 10204 3.1 / 3.2 certification
Third-party inspection (SGS / BV / TUV upon request)
Full heat number traceability is standard for EPC projects.
Key Advantages for Oil & Gas Pipelines
✔ Excellent resistance to chloride-induced corrosion
✔ High-pressure capability (SCH 80 wall)
✔ Suitable for offshore and onshore pipelines
✔ Superior durability in harsh chemical environments
✔ Good weldability and fabrication flexibility
✔ Long-term operational reliability
FAQ
1️⃣ What is 8" ASTM A312 TP316 SCH 80 stainless steel pipe?
It is an 8-inch nominal diameter austenitic stainless steel pipe manufactured under ASTM International ASTM A312 specification. SCH 80 indicates a thicker wall (10.97 mm / 0.432") suitable for medium to high-pressure pipelines. TP316 contains molybdenum for superior resistance to chloride corrosion and pitting, ideal for oil & gas applications.
2️⃣ Why is TP316 preferred over TP304 in oil & gas pipelines?
TP316 contains 2–3% molybdenum, which increases resistance to pitting and crevice corrosion in saline and chemical environments.
TP304 lacks molybdenum, making it less suitable for offshore pipelines or chloride-rich fluids.
3️⃣ What is Schedule 80 and why is it important?
Schedule 80 (SCH 80) defines the pipe wall thickness under ASME B36.19M.
For 8" pipe: wall thickness = 10.97 mm (0.432").
Provides higher allowable working pressure and better safety margins compared to SCH 40.
4️⃣ Can 8" TP316 SCH 80 withstand high-pressure and high-temperature conditions?
Yes. SCH 80 provides increased structural strength, and TP316 maintains its mechanical integrity in elevated temperature and high-pressure conditions typical of oil & gas pipelines.
5️⃣ Is seamless or welded pipe better for 8" SCH 80 TP316?
| Type | Recommended Use |
|---|---|
| Seamless | High-pressure, critical pipeline sections, offshore service |
| Welded | General industrial piping with moderate pressure |
| EFW | Large-diameter pipelines (>12") |
For high-pressure oil & gas pipelines, seamless pipes are preferred for reliability and uniform wall thickness.
6️⃣ What are typical applications of 8" TP316 SCH 80 pipe in oil & gas?
Offshore and onshore crude oil and gas pipelines
High-pressure process lines
Chemical injection lines
Saltwater handling pipelines
Petrochemical plant process piping
7️⃣ What is the corrosion resistance of TP316?
Excellent against chlorides and seawater
Resistant to pitting and crevice corrosion
Performs well in mild acids and oxidizing environments
For extreme chloride exposure, TP316L or duplex stainless steel may be considered.
8️⃣ Can 8" TP316 SCH 80 be welded and fabricated easily?
Yes. TP316 is highly weldable using TIG, MIG, or arc welding. For critical pipelines, post-weld passivation is recommended to restore corrosion resistance.
9️⃣ What inspection and certification documents are typically provided?
EN 10204 3.1 / 3.2 Mill Test Certificate (MTC)
Chemical composition report
Mechanical test report
Hydrostatic test report
Ultrasonic testing (UT) or radiographic testing (RT)
PMI (Positive Material Identification)
Third-party inspection (SGS / BV / TUV)
Full heat number traceability is standard for EPC and industrial projects.
🔟 How to select a reliable supplier for 8" TP316 SCH 80 stainless pipe?
Compliance with ASTM A312
Accurate dimensional tolerances per ASME B36.19M
Proper chemical and mechanical certificates
Heat number traceability for project accountability
Proven experience in oil & gas or EPC pipeline projects
Ability to support third-party inspection
