ASTM A312 TP316H Welded Stainless Steel Pipe: Manufacturing Capabilities & Product Specifications

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Womic Steel supplies ASTM A312 TP316H welded stainless steel pipe for elevated temperature service where enhanced creep strength is required. TP316H contains higher carbon (0.04-0.10%) than standard 316 (≤ 0.08%) and 316L (≤ 0.03%), providing superior creep rupture strength at temperatures above 550°C (1022°F). Minimum yield strength 205 MPa (30,000 psi), tensile strength 515 MPa (74,700 psi). Manufacturing includes ERW for small diameters and EFW for large diameters, both with full penetration and post-weld solution annealing. Outside diameter from 6.35mm to 1219mm (1/4″ – 48″), wall thickness 0.5mm – 50mm, standard length up to 12m, custom up to 24m. Mill certificate, hydrotest, 100% UT, solution annealed and pickled finish, beveled or plain ends available. Suitable for boiler superheater tubes, heat exchanger shells (high temperature), refinery heater tubes, furnace components (550-750°C), power generation piping, petrochemical high-temperature process lines, pressure vessels for elevated temperature, and superheater headers.

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Welded Stainless Steel Pipe Size: Outside Diameter: 6.35mm – 1,219mm (1/4″ – 48″), Wall Thickness: 0.5mm – 50mm (Schedule 5S, 10S, 40S, 80S, 160), Length: 6m – 12m standard, custom lengths up to 24m

Standard & Grade of Welded Stainless Steel Pipe: ASTM A312 TP316H; also ASME SA312; EN 10217-7 1.4919; Equivalent to AISI 316H; also available TP304H, TP321H, TP347H

Usage of Welded Stainless Steel Pipe: Boiler superheater and reheater tubes, heat exchanger shells and tube sheets (elevated temperature), refinery heater tubes and pigtails, furnace radiant coils, high-temperature chemical reactors, superheater headers, steam transfer lines, pressure vessels for elevated temperature service, furnace components, waste heat recovery systems, petrochemical pyrolysis lines, high-temperature gas cooling lines

Womic Steel offering high quality & competitive prices of ASTM A312 TP316H welded stainless steel pipe, high carbon stainless tube, ERW stainless pipe, EFW stainless pipe, creep resistant stainless pipe, high temperature pipe. Mill certificate EN 10204 3.1/3.2, hydro test, UT, solution annealed, beveled/plain ends, pickled finish available. Factory direct supply for power generation, refinery, and petrochemical 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 TP316H welded pipe production facility utilizes multiple advanced welding technologies with controlled heat input to maintain creep strength:

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. Ideal for small to medium diameter TP316H pipes for superheater tubes and instrumentation.

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 (ER316H or ER316 with higher C).

LSAW / SAWL Line for Stainless: For diameters from 406mm to 1524mm (16″ – 60″), wall thickness up to 50mm. Submerged arc welding of rolled TP316H plates.

All TP316H welded pipes undergo solution annealing (heat treatment) at 1040-1120°C followed by water quenching to dissolve carbides and optimize creep properties, 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 I, VIII) upon request

Womic Steel supplies TP316H welded pipes to over 40 countries across power generation, refinery, and petrochemical 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

ASTM A312 TP316H: Material Composition & Performance Characteristics

ASTM A312 TP316H is the high-carbon version of 316 stainless steel, specifically intended for elevated temperature service where creep strength is important. The higher carbon content (0.04-0.10%) provides increased creep rupture strength compared to standard 316 (≤ 0.08%) and 316L (≤ 0.03%). TP316H also contains molybdenum (2.0-3.0%) for improved pitting resistance in high-temperature chloride environments.

Chemical Composition (Ladle Analysis, % by mass):

Element	TP316H (ASTM A312)	TP316 (for comparison)	TP316L (for comparison)
C	0.04 – 0.10	≤ 0.08	≤ 0.030
Mn	≤ 2.00	≤ 2.00	≤ 2.00
P	≤ 0.045	≤ 0.045	≤ 0.045
S	≤ 0.030	≤ 0.030	≤ 0.030
Si	≤ 1.00	≤ 1.00	≤ 1.00
Cr	16.0 – 18.0	16.0 – 18.0	16.0 – 18.0
Ni	10.0 – 14.0	10.0 – 14.0	10.0 – 14.0
Mo	2.0 – 3.0	2.0 – 3.0	2.0 – 3.0
Fe	Balance	Balance	Balance

Mechanical Properties (Room Temperature, Solution Annealed):

Property	TP316H
Yield Strength (min, 0.2% offset)	205 MPa (30,000 psi)
Tensile Strength (min)	515 MPa (74,700 psi)
Elongation (min, 50mm gauge)	35%
Hardness (max)	90 HRB

Physical Properties:

Density: 8.00 g/cm³

Modulus of Elasticity: 193 GPa (28 × 10⁶ psi) at room temperature, decreasing at elevated temperature

Thermal Conductivity: 16.3 W/m·K at 100°C

Coefficient of Thermal Expansion: 16.0 × 10⁻⁶/°C (20-100°C)

High-Temperature Properties (Typical):

Allowable stress at 550°C: ≈ 85 MPa (ASME Section II, Part D)

Allowable stress at 650°C: ≈ 40 MPa (significantly higher than 316L)

Creep rupture strength (100,000 hr at 600°C): ≈ 80 MPa

Oxidation resistance: Good up to 850°C in air

Comparison with 316 and 316L:

TP316H has higher creep strength than 316 and 316L at temperatures above 550°C

TP316H has lower resistance to intergranular corrosion after welding (use 316L for welded service without PWHT)

For temperatures below 550°C, 316L is sufficient; above 550°C, TP316H is preferred

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, 160 (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
Tolerances	OD: ±0.5% or ±3.2mm; WT: ±12.5% (per ASTM A999); Length: +50mm / -0mm

*Custom dimensions outside these ranges available. TP316H is typically specified with solution annealed condition; for creep-critical applications, grain size control (ASTM 5-7) is often required.*

Common High-Temperature Stainless Steel Standards & Grades Manufactured by Womic Steel

Standard	Steel Grades	Typical Application	Welding Process
ASTM A312	TP316H, TP304H, TP321H, TP347H	High temperature, creep resistant	ERW/EFW/LSAW
ASTM A358	TP316H, TP304H, TP347H	Electric fusion welded, high temp	EFW
ASTM A249	TP316H, TP304H	Boiler, superheater, heat exchanger	ERW/EFW
ASTM A312	TP316L, TP304L	General corrosive service (low temp)	ERW/EFW/LSAW
EN 10217-7	1.4919 (316H), 1.4948 (304H)	Pressure purposes, high temp	SAW/ERW

Usage: Superheater tubes, boiler headers, heat exchangers (high temp), refinery heater tubes, high-temperature chemical reactors.

Manufacturing Process – Welded Stainless Steel Pipe (ERW, EFW, LSAW)

Womic Steel employs three primary welding processes for TP316H pipe production. The higher carbon content requires careful control to avoid carbide precipitation during welding and heat treatment.

ERW (Electric Resistance Welding) Process – Small to Medium Diameter (6.35–610mm OD):

Raw Material (Strip/Coil) Inspection: TP316H strip verified for composition (Cr 16-18%, Ni 10-14%, Mo 2-3%, C 0.04-0.10%). Each coil has unique heat number.

Uncoiling & Leveling

Strip Edge Trimming

Forming: Continuous roll forming.

High-Frequency Welding: Heat input controlled (≤ 1.5 kJ/mm) to avoid carbide precipitation.

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 carbides.

Hydrostatic Test

Pickling & Passivation

Final Inspection & Marking

EFW (Electric Fusion Welding) Process – Large Diameter (219–1219mm OD, 4.0–50mm WT):

Plate Preparation: TP316H plate, edges beveled (X bevel).

Roll Forming

Tack Welding

TIG (GTAW) Root Pass: Matching filler (ER316H or ER316), argon backing gas.

SAW Fill & Cap Passes: Multi-pass SAW with controlled heat input, 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 & Marking

LSAW Process for Stainless – Very Large Diameter (406–1524mm OD, 6.0–50mm WT):

UOE or JCOE forming from TP316H plate

Double-sided SAW welding

Full solution annealing after welding

Special Considerations for TP316H:

Higher carbon requires faster cooling after solution annealing (water quench mandatory)

Avoid prolonged exposure in sensitization range (425-870°C)

For field welding, 316L filler may be used to avoid sensitization in HAZ

Quality Control & Testing Procedures for ASTM A312 TP316H Welded Stainless Steel Pipe

Stage	Inspection Method	Purpose
Raw Material	Chemical Analysis (OES)	Verify TP316H (C 0.04-0.10%, Mo 2.0-3.0%)
Raw Material	Tensile Testing	Yield ≥ 205 MPa, Tensile ≥ 515 MPa
Raw Material	Grain Size (ASTM E112)	Typically ASTM 5-7 for creep strength
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	Intergranular Corrosion Test (A262 E)	Detect sensitization (must pass for most specs)
Finished Pipe	Hydrostatic Test	Pressure integrity
Finished Pipe	Flattening / Guided Bend	Ductility
Finished Pipe	PMI	Confirm grade (Cr, Ni, Mo)
Finished Pipe	Elevated Temperature Tensile (if specified)	Verify strength at operating temp
Finished Pipe	Visual & Marking	Traceability

Optional Tests for High-Temperature Service:

Elevated temperature tensile test (e.g., at 600°C)

Creep rupture test (for critical creep applications)

Carburization resistance test (for service in carbon-containing atmospheres)

Primary Applications – ASTM A312 TP316H Welded Stainless Steel Pipe

Boiler superheater and reheater tubes: In fossil fuel power plants and heat recovery steam generators (HRSG), where steam temperatures reach 550-650°C. TP316H provides higher creep strength than 304H and better pitting resistance than 304H.

Heat exchanger shells and tube sheets: Shell and tube heat exchangers operating at elevated temperatures (above 500°C) where 316L would lose strength.

Refinery heater tubes and pigtails: Fired heater radiant and convection sections handling high-temperature hydrocarbons (> 550°C).

Superheater headers: Main steam headers in power plants requiring high creep strength and oxidation resistance.

Steam transfer lines: Piping between boiler and turbine in fossil and combined-cycle power plants.

Pressure vessels for elevated temperature service: ASME Section VIII vessels operating above 550°C.

Furnace components: Radiant tubes, burner tips, and furnace baffles requiring creep resistance.

Petrochemical pyrolysis lines: High-temperature (600-750°C) cracking furnace outlet lines where carburization and creep are concerns.

Waste heat recovery systems: Heat exchanger piping in gas turbine combined cycle plants.

High-temperature gas cooling lines: Gas-to-gas heat exchangers in refinery and petrochemical processes.

Packaging & Shipping – ASTM A312 TP316H Welded Stainless Steel Pipe

Packaging:

Anti-corrosion protection: Pipes oiled or VCI paper.

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 high-temperature 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 creep test reports upon request.

Womic Steel Advantages & FAQ – ASTM A312 TP316H Welded Stainless Steel Pipe

Why Partner with Womic Steel for TP316H Welded Pipe?

Complete Size Range: ERW 1/4″ – 24″, EFW/LSAW 8″ – 60″.

Full solution annealing after welding (1040-1120°C, water quench).

Grain size control (ASTM 5-7) for optimal creep strength.

Elevated temperature tensile and creep testing available.

Competitive lead times: 25-35 days for ERW, 35-50 days for EFW/LSAW.

Global Certification: ISO 9001, PED (CE), EN 10204 Type 3.2.

Frequently Asked Questions (FAQ) – ASTM A312 TP316H Welded Pipe

Q: What is the difference between TP316H and TP316L?
A: TP316H has higher carbon (0.04-0.10% vs ≤ 0.03% for 316L), which provides significantly higher creep rupture strength at temperatures above 550°C. 316L is more resistant to intergranular corrosion after welding. For applications with sustained high temperatures (above 550°C) and stresses, use TP316H. For welded equipment without post-weld heat treatment, 316L is preferred to avoid sensitization.

Q: Can TP316H be used in the as-welded condition?
A: For pressure-containing applications, ASTM A312 requires solution annealing after welding. For field welding of TP316H, post-weld heat treatment (solution annealing) is generally not practical, so many fabricators use 316L filler metal to avoid sensitization in the HAZ. Womic supplies TP316H pipes in the solution annealed condition; field welding should use appropriate filler (e.g., 316L) and low heat input.

Q: What is the maximum service temperature for TP316H?
A: TP316H has allowable stress values in ASME Section II, Part D up to 815°C (1500°F). However, for long-term creep service, it is typically used up to 700°C. Above 700°C, grades with higher chromium (309, 310, or nickel alloys) may be required for oxidation resistance.

Q: How does TP316H compare to TP304H for high-temperature service?
A: TP316H contains molybdenum (2-3%), which provides better pitting resistance and higher high-temperature strength than 304H. In chloride-containing high-temperature environments (e.g., some refinery streams), 316H is preferred. In clean oxidizing atmospheres, 304H may be sufficient and more economical.

Q: Is solution annealing required for TP316H welded pipe?
A: Yes, per ASTM A312. Solution annealing at 1040-1120°C followed by water quench is required to dissolve carbides and achieve the specified mechanical properties and corrosion resistance. Without proper solution annealing, the pipe may have reduced creep strength and susceptibility to intergranular corrosion. Womic performs full solution annealing on all TP316H welded pipes.

Q: What welding filler metal is recommended for TP316H?
A: For welding TP316H, AWS A5.9 ER316H (matching higher carbon) is recommended for matching creep strength. However, for field welding where post-weld heat treatment is not possible, ER316L is often used to avoid sensitization in the HAZ. The designer should specify based on service temperature.

Q: What is the typical lead time for TP316H welded stainless steel pipe?
A: 25-35 days for ERW (small to medium diameters), 35-50 days for EFW/LSAW (large diameters). TP316H lead times are similar to 316L.

Q: Does TP316H require grain size control for creep service?
A: For elevated temperature service where creep is a design consideration, ASME Section I and VIII require grain size control. TP316H typically has ASTM grain size 5-7. Womic can provide grain size measurement reports upon request.

Project Reference – Southeast Asia Combined Cycle Power Plant Superheater Piping

Country: Thailand (Rayong, Map Ta Phut industrial estate – gas-fired power plant)
Standard & Grade: ASTM A312 TP316H (welded) – with supplementary creep testing
Dimensions & Quantity:

OD 168.3mm (6″) × Schedule 80S (10.97mm WT) – 800 meters (approx. 28 tons) – ERW process

OD 219.1mm (8″) × Schedule 80S (12.70mm WT) – 500 meters (approx. 25 tons) – EFW process

OD 273.0mm (10″) × Schedule 80S (15.09mm WT) – 300 meters (approx. 24 tons) – EFW process

OD 60.3mm (2″) × Schedule 80S (5.54mm WT) – 1,200 meters (approx. 7 tons) – ERW process
Total: 2,800 meters, approx. 84 tons

Specifications: ASTM A312 TP316H solution annealed and pickled, beveled ends. Hydrostatic testing. 100% UT for EFW pipes, eddy current for ERW. PMI on every pipe. Mandatory grain size measurement (ASTM 5-7, achieved 5.5-6.5). Charpy impact at -20°C (spec 27J, achieved 80-130J). Elevated temperature tensile test at 600°C (spec: yield ≥ 80 MPa, achieved 110-140 MPa; tensile ≥ 200 MPa, achieved 250-300 MPa). Creep rupture test at 600°C, 60 MPa for 1,000h – no rupture. Intergranular corrosion test per ASTM A262 Practice E (pass – sensitization not observed). Third-party inspection by TÜV Thailand.

Application: Superheater outlet headers and transfer piping in a combined cycle power plant (gas turbine + HRSG). The superheater section produces steam at 560°C, 12.5 MPa. The piping connects the superheater outlet to the high-pressure steam turbine. The previous 304H piping suffered from inadequate creep strength and oxidation after 10 years of cyclic operation. TP316H was selected for its higher creep strength and better pitting resistance (from Mo) in the event of chloride ingress from poor water chemistry.

Technical Challenges & Solutions:

Creep strength at 560°C and 12.5 MPa – TP316H with carbon 0.06-0.08% and grain size ASTM 6 provided creep rupture strength of 70 MPa at 600°C for 100,000 hr (predicted). Womic performed 1,000h creep test at 600°C, 60 MPa – no rupture, total elongation 14%. Client accepted the material.

Grain size control for ASME Section I compliance – Superheater piping requires ASTM grain size 5-7 per ASME (finer grain provides better creep resistance but lower oxidation resistance at very high temp). Womic controlled grain size through solution annealing temperature (1090-1120°C) and cooling rate. Results: ASTM 5.5-6.5 on base metal, ASTM 6-7 on weld. Acceptable.

Weld metal creep strength matching – EFW and ERW welds must have creep strength equal to base metal. Womic used ER316H filler for EFW and optimized ERW parameters to achieve full weld joint efficiency. Elevated temperature tensile at 600°C on weld samples: yield 105-125 MPa, tensile 230-280 MPa – comparable to base metal.

Oxidation resistance at 560°C – TP316H forms a protective Cr₂O₃ scale at 560°C. Womic performed oxidation test (air at 600°C for 500h): weight gain 0.12 mg/cm². Acceptable.

Field welding procedure for superheater repair – The plant's maintenance team needed a qualified WPS for field welds (pipe to flange, pipe to pipe). Womic provided 25 weld coupons with WPS using GTAW, ER316L filler (to avoid sensitization), preheat 10-20°C, interpass ≤ 150°C, heat input ≤ 1.5 kJ/mm. Coupons passed RT, PT, and elevated temperature tensile at 600°C. Client qualified the procedure.

Logistics to Rayong power plant – Pipes shipped from Shanghai to Laem Chabang port, then trucked to the power plant. TÜV Thailand inspected pipes at port. All 84 tons delivered in 3 shipments over 8 weeks. No non-conformances.

Result: Superheater piping installed during Q3 2024 outage. After 12 months of operation at 560°C, 12.5 MPa, in-line inspection showed no creep deformation, no oxidation scaling, and no cracking. The plant expects 20+ year service life (vs 10 years for 304H). Womic Steel is now a qualified supplier for this power plant's high-temperature alloy needs for future upgrades.

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 TP316H welded stainless steel pipes for power plant superheaters, refinery heaters, high-temperature heat exchangers, and petrochemical process piping worldwide.