Product Description
Welded Stainless Steel Pipe Size: Outside Diameter: 6.35mm – 1,219mm (1/4″ – 48″), Wall Thickness: 0.5mm – 50mm (Schedule 5S, 10S, 40S, 80S), Length: 6m – 12m standard, custom lengths up to 24m
Standard & Grade of Welded Stainless Steel Pipe: ASTM A312 TP316N; also ASME SA312; EN 10217-7 1.4406; Equivalent to AISI 316N
Usage of Welded Stainless Steel Pipe: Pressure vessels and storage tanks (higher pressure rating), offshore platform topside piping (higher strength reduces weight), chemical processing (higher pressure chloride service), heat exchanger shells and tubes (higher design pressure), paper mill equipment (digester blow lines, stock lines), marine applications (boat rails, equipment requiring higher strength with corrosion resistance), high-pressure water treatment systems (reverse osmosis feed lines), pump and valve bodies, structural components in corrosive environments, brewery and dairy piping (higher operating pressures), hydraulic lines in marine environments
Womic Steel offering high quality & competitive prices of ASTM A312 TP316N welded stainless steel pipe, nitrogen strengthened stainless tube, high strength ERW stainless pipe, EFW stainless pipe, high yield stainless pipe. Mill certificate EN 10204 3.1/3.2, hydro test, UT, solution annealed, beveled/plain ends, pickled/polished finish available. Factory direct supply for offshore, pressure vessel, and chemical projects worldwide.
Womic Steel: Manufacturing Capabilities & Company Strength
Womic Steel Group is a premier manufacturer and global exporter with over 20 years of expertise in producing stainless steel tubular products. Our specialized TP316N welded pipe production facility utilizes multiple advanced welding technologies with controlled heat input to retain nitrogen in the weld metal:
ERW (Electric Resistance Welding) Line: For diameters from 6.35mm to 610mm (1/4″ – 24″), wall thickness from 0.5mm to 12.7mm. High-frequency welding with optimized parameters to minimize nitrogen loss. Ideal for small to medium diameter TP316N pipes for pressure and structural applications.
EFW (Electric Fusion Welding) Line: For diameters from 219mm to 1219mm (8″ – 48″), wall thickness from 4.0mm to 50mm. TIG (GTAW) root pass with SAW fill passes, using matching filler metal (ER316N or ER316 with nitrogen shielding).
LSAW / SAWL Line for Stainless: For diameters from 406mm to 1524mm (16″ – 60″), wall thickness up to 50mm. Submerged arc welding of rolled TP316N plates.
All TP316N welded pipes undergo solution annealing (heat treatment) at 1040-1120°C followed by water quenching to retain nitrogen in solid solution and restore corrosion resistance, followed by pickling and passivation.
Quality Certifications & Regulatory Compliance:
ISO 9001:2015 Certified
PED 2014/68/EU (CE Marking) for pressure equipment
EN 10204 3.2 Certification with third-party validation (TÜV, BV, SGS, LR)
Third-Party Inspection (TPI) approved by SGS, BV, ABS, DNV, TÜV
ASME Boiler and Pressure Vessel Code (Section VIII, Div. 1) upon request
Womic Steel supplies TP316N welded pipes to over 35 countries across offshore, pressure vessel, and chemical industries.
Production Flexibility:
ERW: 6.35–610mm OD × 0.5–12.7mm WT × ≤ 12m
EFW: 219–1219mm OD × 4.0–50mm WT × ≤ 12m (longer upon request)
LSAW: 406–1524mm OD × 6.0–50mm WT × ≤ 18m
Finishing options: Annealed and pickled, bright annealed, polished
ASTM A312 TP316N: Material Composition & Performance Characteristics
ASTM A312 TP316N is a nitrogen-strengthened version of 316 stainless steel. Nitrogen (0.10-0.16%) provides solid solution strengthening, increasing yield strength by approximately 35% while maintaining excellent ductility, toughness, and corrosion resistance. The molybdenum content (2.0-3.0%) provides superior pitting and crevice corrosion resistance in chloride environments compared to 304N.
Chemical Composition (Ladle Analysis, % by mass):
| Element | TP316N (ASTM A312) | TP316 (for comparison) |
| C | ≤ 0.08 | ≤ 0.08 |
| Mn | ≤ 2.00 | ≤ 2.00 |
| P | ≤ 0.045 | ≤ 0.045 |
| S | ≤ 0.030 | ≤ 0.030 |
| Si | ≤ 1.00 | ≤ 1.00 |
| Cr | 16.0 – 18.0 | 16.0 – 18.0 |
| Ni | 10.0 – 14.0 | 10.0 – 14.0 |
| Mo | 2.0 – 3.0 | 2.0 – 3.0 |
| N | 0.10 – 0.16 | ≤ 0.10 |
| Fe | Balance | Balance |
Mechanical Properties (Room Temperature, Solution Annealed):
| Property | TP316N | TP316 |
| Yield Strength (min, 0.2% offset) | 275 MPa (39,900 psi) | 205 MPa (30,000 psi) |
| Tensile Strength (min) | 550 MPa (79,800 psi) | 515 MPa (74,700 psi) |
| Elongation (min, 50mm gauge) | 35% | 40% |
| Hardness (max) | 90 HRB | 90 HRB |
Physical Properties:
Density: 7.98 g/cm³
Modulus of Elasticity: 200 GPa (29 × 10⁶ psi)
Thermal Conductivity: 16.3 W/m·K at 100°C
Coefficient of Thermal Expansion: 16.0 × 10⁻⁶/°C (20-100°C)
Corrosion Resistance:
Pitting Resistance Equivalent Number (PREN) = Cr% + 3.3(Mo%) + 16(N%). For TP316N, PREN ≈ 18 + 3.3×2.5 + 16×0.13 = 27-30 (vs 316 PREN ≈ 24-26)
Excellent resistance to pitting and crevice corrosion in chloride environments (better than 316)
Good resistance to organic acids and many chemical environments
Slightly improved resistance to intergranular corrosion due to nitrogen
Not suitable for high-temperature chloride service above 60°C without higher alloys
Key Advantages over 316:
35% higher yield strength allows thinner walls (weight reduction 20-25%)
Higher allowable stress per ASME Section VIII for pressure vessels
Improved pitting resistance (higher PREN)
Comparable weldability and formability
Dimensional Range & Standards Compliance
| Item | Specification |
| Standard | ASTM A312 / ASME SA312 (also A358, A249) |
| Manufacturing Processes | ERW, EFW, LSAW |
| Outside Diameter Range | ERW: 6.35 – 610mm; EFW/LSAW: 219 – 1524mm |
| Wall Thickness Range | ERW: 0.5 – 12.7mm; EFW/LSAW: 4.0 – 50mm |
| Schedule Range | 5S, 10S, 40S, 80S (for NPS 1/8″ – 48″) |
| Length Range | Standard: 6m; Extended: 12m, 18m, up to 24m |
| End Finish | Plain End (PE), Beveled End (BE) |
| Surface Finish | Annealed & Pickled, Bright Annealed, Polished |
| Tolerances | OD: ±0.5% or ±3.2mm; WT: ±12.5% (per ASTM A999); Length: +50mm / -0mm |
Available Dimensions & Specifications – ASTM A312 TP316N Welded Stainless Steel Pipe (Selected Typical Sizes)
| NPS | OD (mm) | Schedule | WT (mm) | Weight (kg/m) | Standard Length | Typical Application |
| 1/2″ | 21.3 | 10S | 2.11 | 1.00 | 6m | Hydraulic line |
| 3/4″ | 26.7 | 10S | 2.11 | 1.28 | 6m | Chemical dosing |
| 1″ | 33.4 | 10S | 2.77 | 2.09 | 6m | High pressure water |
| 1-1/2″ | 48.3 | 10S | 2.77 | 3.11 | 6m | Process line |
| 2″ | 60.3 | 10S | 2.77 | 3.93 | 6m / 12m | Pressure vessel |
| 3″ | 88.9 | 10S | 3.05 | 6.46 | 6m / 12m | Offshore piping |
| 4″ | 114.3 | 10S | 3.05 | 8.37 | 6m / 12m | Heat exchanger |
| 6″ | 168.3 | 10S | 3.40 | 13.8 | 6m / 12m | Chemical process |
| 8″ | 219.1 | 10S | 3.76 | 20.0 | 12m | Main header |
| 10″ | 273.0 | 10S | 4.19 | 27.8 | 12m | Structural support |
| 12″ | 323.9 | 10S | 4.57 | 36.0 | 12m | Large diameter |
| 16″ | 406.4 | 10S | 4.78 | 47.4 | 12m | Pressure vessel shell |
*Custom dimensions outside these ranges available. TP316N allows thinner walls than 316 for same pressure rating (20-25% weight savings).*
Common Stainless Steel Standards & Grades Manufactured by Womic Steel
| Standard | Steel Grades | Typical Application | Welding Process |
| ASTM A312 | TP316N, TP304N, TP316, TP304 | High strength corrosive service | ERW/EFW/LSAW |
| ASTM A358 | TP316N, TP304N | Electric fusion welded, high strength | EFW |
| ASTM A249 | TP316N | Boiler, heat exchanger | ERW/EFW |
| ASTM A312 | TP316L, TP304L | General corrosive service | ERW/EFW/LSAW |
| EN 10217-7 | 1.4406 (316N) | Pressure purposes, high strength | SAW/ERW |
Usage: Pressure vessels, offshore topside piping, chemical processing (higher pressure), heat exchangers, marine structures, high-pressure water treatment.
Manufacturing Process – Welded Stainless Steel Pipe (ERW, EFW, LSAW)
Womic Steel employs three primary welding processes for TP316N pipe production. Maintaining nitrogen content in the weld metal is critical; excessive heat input can cause nitrogen loss.
ERW (Electric Resistance Welding) Process – Small to Medium Diameter (6.35–610mm OD):
Raw Material (Strip/Coil) Inspection: TP316N strip verified for composition (Cr 16-18%, Ni 10-14%, Mo 2-3%, N 0.10-0.16%). Each coil has unique heat number.
Uncoiling & Leveling
Strip Edge Trimming
Forming: Continuous roll forming.
High-Frequency Welding: Optimized heat input (≤ 1.5 kJ/mm) to retain nitrogen. Higher speeds may be required.
Seam Annealing: Induction annealing followed by water quench.
Sizing & Straightening
Cutting to Length
NDT: Eddy current test (100%) + optional UT.
Solution Annealing (Full Pipe): 1040-1120°C, water quench. Critical for dissolving nitrides.
Hydrostatic Test
Pickling & Passivation
PMI (XRF) & Nitrogen verification (if specified)
Final Inspection & Marking
EFW (Electric Fusion Welding) Process – Large Diameter (219–1219mm OD, 4.0–50mm WT):
Plate Preparation: TP316N plate, edges beveled (X bevel).
Roll Forming
Tack Welding
TIG (GTAW) Root Pass: Matching filler (ER316N or ER316 with nitrogen), argon backing gas.
SAW Fill & Cap Passes: Multi-pass SAW with controlled heat input (≤ 1.8 kJ/mm), interpass ≤ 150°C.
Inner Weld
100% Radiographic Testing (per ASTM A358)
Solution Annealing: Full pipe heat treatment (1040-1120°C), water quench.
Pickling & Passivation
Hydrostatic Test
Dimensional Inspection & MarkingLSAW Process for Stainless – Very Large Diameter (406–1524mm OD, 6.0–50mm WT):
UOE or JCOE forming from TP316N plate
Double-sided SAW welding
Full solution annealing after welding
Special Considerations for TP316N:
Nitrogen content must be controlled to avoid nitride precipitation
Solution annealing temperature at higher end of range (1080-1120°C) to fully dissolve nitrides
Water quench mandatory to retain nitrogen in solid solution
Welding consumables should have matching nitrogen content (ER316 with N addition)
Quality Control & Testing Procedures for ASTM A312 TP316N Welded Stainless Steel Pipe
| Stage | Inspection Method | Purpose |
| Raw Material | Chemical Analysis (OES + Combustion for N) | Verify TP316N (N 0.10-0.16%, Mo 2.0-3.0%, Cr 16-18%, Ni 10-14%) |
| Raw Material | Tensile Testing | Verify yield ≥ 275 MPa, tensile ≥ 550 MPa |
| Raw Material | Hardness | ≤ 90 HRB |
| In-Process | Heat Input Monitoring | ≤ 1.8 kJ/mm |
| Weld (ERW) | Eddy Current (100%) | Weld integrity |
| Weld (EFW/LSAW) | 100% UT (or PAUT) | Detect weld defects |
| Weld (EFW/LSAW) | RT (spot or 100% per spec) | Weld quality |
| Weld | Dye Penetrant (PT) | Surface cracks |
| After Solution Annealing | Hardness Test | ≤ 90 HRB |
| After Solution Annealing | Nitrogen Verification (if specified) | Confirm N content in finished pipe |
| Finished Pipe | Hydrostatic Test | Pressure integrity |
| Finished Pipe | Flattening / Guided Bend | Ductility |
| Finished Pipe | PMI (XRF) | Confirm grade (Cr, Ni, Mo) |
| Finished Pipe | Pitting Corrosion Test (ASTM G48) | Verify pitting resistance (if specified) |
| Finished Pipe | Visual & Marking | Traceability |
Optional Tests:
Elevated temperature tensile test (if required for design)
Intergranular corrosion test (ASTM A262 Practice E) for welded applications
G48 pitting test for chloride service qualification
Primary Applications – ASTM A312 TP316N Welded Stainless Steel Pipe
Pressure vessels and storage tanks: Higher allowable stress allows thinner walls (20-25% weight savings) compared to 316, reducing material cost and weight.
Offshore platform topside piping: Process piping in marine environments requiring higher strength and corrosion resistance. Weight reduction is critical for offshore platforms.
Chemical processing (higher pressure chloride service): Reactor inlet/outlet piping, high-pressure transfer lines handling chloride-containing chemicals at moderate temperatures.
Heat exchanger shells and tubes: Shell side pressure can be increased without thickening shell. Tubes can have thinner walls for better heat transfer.
Paper mill equipment: Digester blow lines (higher strength to resist thermal and pressure cycling), stock preparation piping.
Marine applications: Boat rails, davit structures, equipment supports requiring higher strength with corrosion resistance.
High-pressure water treatment systems: Reverse osmosis feed lines (higher pressure rating than 316), desalination high-pressure piping.
Pump and valve bodies: Cast or fabricated components where higher pressure rating is needed without upgrading to duplex.
Brewery and dairy piping: High-pressure CIP systems and product lines requiring higher operating pressures.
ydraulic lines in marine environments: Instrumentation and control lines requiring higher burst pressure with corrosion resistance.
Packaging & Shipping – ASTM A312 TP316N Welded Stainless Steel Pipe
Packaging:
Anti-corrosion protection: Pipes oiled or VCI paper. For food/brewing, no oil residue (plastic wrap).
End caps: Plastic caps for beveled ends.
Bundling (Small diameters): Bundles with steel straps and interleaving paper.
Individual packaging (Large diameters): Plastic film wrap.
Wooden crates for critical applications.
Shipping:
Containers for ≤ 610mm, break-bulk for larger diameters.
Documentation: MTC 3.1/3.2, hydrotest report, eddy current/UT reports, PMI report, dimensional report, packing list, COO. Optional nitrogen verification report upon request.
Womic Steel Advantages & FAQ – ASTM A312 TP316N Welded Stainless Steel Pipe
Why Partner with Womic Steel for TP316N Welded Pipe?
Complete Size Range: ERW 1/4″ – 24″, EFW/LSAW 8″ – 60″.
Full solution annealing after welding (1040-1120°C, water quench).
Nitrogen content verified (0.10-0.16%) for guaranteed high strength.
Higher strength allows thinner walls – weight savings of 20-25% over 316.
Improved pitting resistance (higher PREN than 316).
Competitive lead times: 25-35 days for ERW, 35-50 days for EFW/LSAW
Frequently Asked Questions (FAQ) – ASTM A312 TP316N Welded Pipe
Q: What is the advantage of TP316N over standard 316?
A: TP316N has 35% higher yield strength (275 MPa vs 205 MPa) and slightly better pitting resistance (PREN 27-30 vs 24-26) while maintaining similar corrosion resistance, ductility, and weldability. This allows designers to use thinner walls for pressure vessels and piping, reducing weight by 20-25% and lowering overall material cost for the same pressure rating.
Q: Is TP316N more expensive than 316?
A: Slightly, due to nitrogen alloying and tighter composition control. However, the weight savings (20-25% thinner walls) often result in lower overall material cost for pressure-containing applications. For structural applications where strength is critical, the weight reduction may offset the higher unit price.
Q: Can TP316N be used in seawater service?
A: TP316N has better pitting resistance than 316, but for continuous seawater immersion at ambient temperature, duplex 2205 or super duplex is still recommended. TP316N may be acceptable for splash zone, intermittent contact, or low-velocity seawater at temperatures below 30°C. For higher temperatures or higher chlorides, consider super duplex.
Q: Does TP316N require solution annealing after welding?
A: ASTM A312 requires solution annealing for welded pipe. For TP316N, solution annealing at 1040-1120°C followed by water quench is necessary to dissolve any nitrides that may have formed during welding and to restore full corrosion resistance and mechanical properties. Womic performs solution annealing on all TP316N welded pipes.
Q: What is the typical allowable stress for TP316N in ASME Section VIII?
A: At room temperature, allowable stress for TP316N is approximately 138 MPa (20,000 psi) vs 115 MPa (16,700 psi) for 316 – about 20% higher. The actual values depend on temperature; refer to ASME Section II, Part D. Designers should use the correct allowable stress values for the specific grade.
Q: What is the typical lead time for TP316N welded stainless steel pipe?
A: 25-35 days for ERW (small to medium diameters), 35-50 days for EFW/LSAW (large diameters). TP316N lead times are similar to 316.
Q: Can TP316N be used for high-temperature service (above 500°C)?
A: TP316N’s high-temperature strength is better than 316 due to nitrogen solid solution strengthening. However, for sustained service above 550°C, grades with higher carbon (316H, 316Ti) or creep-resistant grades (321H, 347H) may be preferred due to better creep properties. TP316N is best suited for moderate temperatures (< 450°C) where strength is needed.
Project Reference – Middle East SWRO Desalination High-Pressure Piping
Country: United Arab Emirates (Abu Dhabi)
Standard & Grade: ASTM A312 TP316N (welded)
Dimensions & Quantity:
OD 219.1mm (8″) × Schedule 10S (3.76mm WT) – 1,500 meters (approx. 28 tons) – EFW process
OD 168.3mm (6″) × Schedule 10S (3.40mm WT) – 2,000 meters (approx. 24 tons) – ERW process
OD 114.3mm (4″) × Schedule 10S (3.05mm WT) – 2,500 meters (approx. 20 tons) – ERW process
OD 60.3mm (2″) × Schedule 10S (2.77mm WT) – 3,000 meters (approx. 11 tons) – ERW process
Total: 9,000 meters, approx. 83 tons
Specifications: ASTM A312 TP316N solution annealed and pickled, beveled ends. Hydrostatic testing at 1.5× design pressure (design 4.0 MPa, test 6.0 MPa). 100% UT for EFW pipes, eddy current for ERW. PMI on every pipe. Tensile testing (yield ≥ 275 MPa, achieved 310-350 MPa; tensile ≥ 550 MPa, achieved 580-630 MPa). Charpy impact at 0°C (min 27J, achieved 90-140J). Pitting corrosion test per ASTM G48 Method A (24h at 22°C) – no pitting. Third-party inspection by BV (Bureau Veritas) UAE.
Application: High-pressure piping for a seawater reverse osmosis (SWRO) desalination plant in Abu Dhabi. The piping carries seawater at 25-35°C, salinity 45,000 ppm (Arabian Gulf), at pressures up to 4.0 MPa (580 psi). The previous 316L piping was adequate for corrosion but required thicker walls to withstand the pressure, resulting in higher weight and cost. TP316N was selected for its higher yield strength (275 MPa vs 316L's 170 MPa), allowing thinner Schedule 10S walls instead of Schedule 40S, saving 55% weight and reducing structural support costs.
Technical Challenges & Solutions:
Pitting resistance in Arabian Gulf seawater – Seawater temperature 35°C in summer, salinity 45,000 ppm. 316L would be borderline. TP316N with higher PREN (27-30 vs 316L 24-26) provided better pitting resistance. Womic performed G48 pitting test at 22°C and 35°C (simulated summer) – no pitting at 22°C; at 35°C, slight pitting started after 72h on weld samples, but acceptable for 25-year design life with cathodic protection. Client accepted.
Weight reduction using Schedule 10S – TP316N's higher strength allowed Schedule 10S (3.76mm for 8″) instead of Schedule 40S (8.18mm) used for 316L. Weight reduced from 1.14 tons per 12m to 0.52 tons per 12m – 54% savings. Total weight saving for the project: 97 tons (original 180 tons vs actual 83 tons). Womic provided design stress calculations per ASME B31.3.
Weld metal strength matching – ERW and EFW welds must have strength equal to base metal for the higher allowable stress. Womic optimized ERW parameters to achieve weld joint efficiency of 95% (tensile strength 590 MPa vs base 610 MPa). EFW welds using ER316N filler achieved 100% joint efficiency. All weld tensile tests passed at 6.0 MPa hydrotest.
Field welding procedure for TP316N – The installation contractor needed a qualified WPS. Womic provided 20 weld coupons with WPS using GTAW with ER316 filler (no specific N filler), interpass ≤ 150°C, heat input ≤ 1.5 kJ/mm. Coupons passed RT, PT, and tensile testing. Client qualified the procedure.
Logistics to Abu Dhabi – Pipes shipped from Shanghai to Khalifa Port in two shipments. BV inspected pipes at port of loading. All 83 tons delivered within 6 weeks. No non-conformances
Result: SWRO high-pressure piping installed in Q2 2024. After 12 months of operation at 4.0 MPa, 35°C seawater, no pitting or corrosion has been observed. The weight savings of 97 tons reduced the building structural steel requirement by an estimated 40 tons, saving $250,000 in construction costs. The client has adopted TP316N as the standard grade for future high-pressure seawater piping in their Middle East desalination plants.
Contact:
Website: www.womicsteel.com
E-mail: sales@womicsteel.com
Tel / WhatsApp / WeChat:
Victor: +86 15575100681
Jack: +86 18390957568
Womic Steel – Your reliable partner for ASTM A312 TP316N welded stainless steel pipes for desalination, offshore platforms, pressure vessels, and high-pressure water treatment applications worldwide.
Related Products
-
ASTM A312 TP316N Welded Stainless Steel Pipe: M...
-
ASTM A312 TP316N Welded Stainless Steel Pipe: M...
-
ASTM A312 TP316H Welded Stainless Steel Pipe: M...
-
ASTM A790 S32760 Super Duplex Stainless Steel W...
-
ASTM A312 TP310S / TP310H Welded Stainless Stee...
-
ASTM A790 S32750 Super Duplex Stainless Steel W...
-
ASTM A312 TP309 / TP309H Welded Stainless Steel...
-
ASTM A790 S31803 Duplex Stainless Steel Welded ...
-
ASTM A312 TP304N Welded Stainless Steel Pipe: M...