Sichuan Liaofu Special Steel Company is one of the most experienced manufacturers and suppliers of seamless 316 stainless steel tubing in China. With over 20 years' experience, our factory offer high quality products made in China with competitive price. Welcome to contact us for wholesale service.
Standard Compliance
ASTM A312 is a standard established by the American Society for Testing and Materials (ASTM) for austenitic stainless steel seamless and welded steel pipes, suitable for high-temperature, high-pressure, and corrosive environments.
TP316, a key grade in this standard, belongs to the 300-series stainless steels and uses molybdenum (Mo) as the primary alloying element to significantly enhance corrosion resistance.
Chemical Composition
| Element | Content Range (%) |
|---|---|
| Carbon (C) | ≤0.08 |
| Chromium (Cr) | 16.0-18.0 |
| Nickel (Ni) | 10.0-14.0 |
| Molybdenum (Mo) | 2.0-3.0 |
| Manganese (Mn) | ≤2.0 |
| Silicon (Si) | ≤1.0 |
| Phosphorus (P) | ≤0.045 |
| Sulfur (S) | ≤0.030 |
Corrosion Resistance
Outstanding Overall Corrosion Resistance: Performs excellently in neutral, oxidizing, and weakly reducing environments, superior to 304 stainless steel.
Pitting and Crevice Corrosion Resistance: Molybdenum significantly enhances resistance to pitting in chloride-containing environments (e.g., seawater, brine).
Intergranular Corrosion Resistance: By controlling carbon content (≤0.08%), carbide precipitation is reduced, avoiding chromium depletion at grain boundaries.
Mechanical Properties
Tensile Strength (σb): ≥515 MPa
Yield Strength (σ0.2): ≥205 MPa
Elongation (δ): ≥30%
Hardness: ≤217 HB (annealed state)
Characteristics: High toughness; strength increases significantly after cold working, but annealing is required to restore plasticity.
High-Temperature Performance
Oxidation Resistance Temperature: Continuous use up to 870°C, intermittent use up to 925°C.
Creep Resistance: Maintains stable strength during long-term use at 500–650°C.
Workability and Weldability
Workability: Capable of cold bending, stamping, etc., but with strong work hardening tendency, requiring intermediate annealing.
Weldability: Suitable for TIG, MIG, shielded metal arc welding, etc. ER316L welding wire or electrodes are recommended to avoid intergranular corrosion.
Production Flow
Billet Preparation: Stainless steel round bars (e.g., electroslag remelted ingots) are used to ensure uniform composition.
Piercing: Hot piercing process (e.g., two-roll skew rolling piercer) to form hollow shell tubes.
Tube Rolling: Wall thickness reduction via cold drawing or cold rolling to improve dimensional accuracy and surface quality.
Heat Treatment: Solution treatment (1010–1120°C rapid cooling) to relieve stress and restore corrosion resistance.
Surface Treatment: Pickling, bright annealing, or polishing to achieve different surface finishes.
Size Range
Outer Diameter: 1/8 inch (3.18 mm) to 24 inches (609.6 mm)
Wall Thickness: 0.028 inch (0.71 mm) to 0.500 inch (12.7 mm)
Special specifications can be customized, with precision complying with ASTM A312 or ASME B36.19 standards.
Application Fields
Chemical and Petrochemical Industry: Reactors, pipelines, heat exchangers (for chloride-containing solutions).
Marine Engineering: Seawater desalination equipment, marine pipelines, offshore platform structural components.
Food and Pharmaceutical Industry: Sterile pipeline systems, fermentation tanks, pharmaceutical equipment (FDA compliant).
Environmental Protection and Water Treatment: Oxidation ditches in wastewater treatment plants, reverse osmosis systems.
Architecture and Decoration: Curtain wall supports, sculptures, coastal building structures.
Routine Inspection Items
Chemical Composition Analysis: Spectroscopic or chemical analysis to ensure compliance with ASTM A312.
Mechanical Property Testing: Tensile testing, hardness testing, impact testing (if required).
Nondestructive Testing:
Eddy Current Testing (ET): Detects surface defects.
Ultrasonic Testing (UT): Detects internal defects.
Intergranular Corrosion Testing: Conducted according to ASTM A262 Practice E or F.
Hydrostatic Test: Each pipe must withstand specified pressure (e.g., 2000 psi) without leakage.
Special Requirements
Can provide low-temperature impact toughness testing (suitable for -196°C liquid nitrogen environments).
Surface roughness inspection (e.g., Ra≤0.8μm for high cleanliness requirements).
Comparison with Other Stainless Steels
| Material | Main Differences | Typical Application Scenarios |
|---|---|---|
| TP316 | Contains 2–3% molybdenum, better pitting resistance than 304, higher cost | Seawater, strongly corrosive chemical environments |
| TP316L | Ultra-low carbon (≤0.03%), superior intergranular corrosion resistance | Welded structures or strongly corrosive environments |
| TP304 | No molybdenum, slightly lower corrosion resistance, lower cost | General corrosion environments (e.g., atmosphere, fresh water) |
| Duplex Steel | Higher strength, resistant to stress corrosion cracking, higher cost | High-pressure, strongly corrosive composite environments |
Precautions
Chloride Environments: Although superior to 304, caution is still required in high-concentration chloride environments (e.g., >1000ppm). 316L or higher grades (e.g., 2205 duplex steel) are recommended.
Welding Control: Avoid high-current welding; post-weld pickling and passivation can be performed to eliminate chromium-depleted layers in heat-affected zones.
Prevention of Iron Contamination: Avoid contact with carbon steel during processing to prevent iron ion contamination and rusting.
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