ASTM A249 TP316L Welded Heat Exchanger Tube
Yuhong Group Co., Ltd. is a recognized supplier of heat transfer equipment and critical components, serving the global energy, petrochemical, and process industries. We manufacture and supply welded heat exchanger tubes, U-tubes, finned tubes, and complete tube bundles, backed by certifications including ISO 9001-2015, PED 2014/68/EU, ABS, DNV, and GOST. Our expertise extends to full heat exchanger fabrication—from tube sheets and baffles to pressure vessels and air-cooled heat exchangers—enabling integrated supply for capital projects worldwide.
ASTM A249 TP316L - Product Overview
ASTM A249 TP316L Welded Austenitic Stainless Steel Tube for Boiler, Superheater, Heat Exchanger, and Condenser Service This specification covers welded tubing in austenitic steel grades, with nominal wall thickness, suitable for high-temperature pressure service. TP316L is the low-carbon variant of grade 316, providing enhanced resistance to intergranular corrosion after welding or stress relieving—a critical factor in heat exchanger fabrication.
Chemical Composition (Ladle Analysis), % Max
| Element |
C |
Mn |
P |
S |
Si |
Cr |
Ni |
Mo |
| ASTM A249 TP316L |
0.035 |
2.00 |
0.045 |
0.030 |
1.00 |
16.0-18.0 |
10.0-14.0 |
2.00-3.00 |
| UNS Designation |
S31603 |
Source: ASTM A249 / ASME SA249 specification
The addition of molybdenum (2.00-3.00%) provides superior resistance to pitting and crevice corrosion in chloride-bearing media compared to 304/304L grades.
Mechanical Properties (Solution Annealed Condition)
| Property |
Requirement (ASTM A249) |
| Tensile Strength, min |
485 MPa (70 ksi) |
| Yield Strength (0.2% offset), min |
170 MPa (25 ksi) |
| Elongation in 2 in. (50 mm), min |
35% |
Source: ASTM A249 / ASME SA249 specification
Manufacturing Requirements & Quality Control
The tubes are manufactured from cold-rolled strip by an automated welding process (typically TIG or high-frequency welding) and must be solution annealed at a minimum temperature of 1040°C (1900°F), followed by water quenching or rapid cooling. This heat treatment is mandatory to dissolve chromium carbides and restore corrosion resistance.
Key manufacturing points:
- Weld seam integrity: The weld bead must be smooth and free from undercut or excessive reinforcement. Post-weld heat treatment is not permitted except for solution annealing as specified.
- Dimensional tolerances: Per ASTM A1016, OD tolerances range from ±0.10 mm for sizes <25.4 mm to ±0.31 mm for 63.5-76.2 mm OD.
- Surface condition: Tubes are typically supplied in bright annealed (BA) condition, with a clean, oxide-free surface.
Mandatory testing per ASTM A249:
- Flattening test
- Flange test (for tube ductility)
- Reverse flattening test
- Hydrostatic test or nondestructive electric test (eddy current)
- Hardness test (HRB ≤ 95 for TP316L)
Special attention: For welded tubes destined for U-bending, the weld seam position and hardness are controlled to prevent stress corrosion cracking in the bend radius.
Complementary Fabrication Capabilities
Beyond bare tubes, Yuhong Group supplies fully integrated heat exchanger components. Our manufacturing scope includes:
- Tube sheets - drilled and grooved to match tube layout
- Baffles - segmental, disk-and-doughnut, or custom designs
- Channel covers and shells - carbon steel, stainless, or clad materials
Material matching: We offer tube sheets in SA-240 316L, SA-516 Gr.70, or duplex grades, ensuring compatibility with TP316L tube-to-tubesheet welding and expansion.
Application Scenarios
ASTM A249 TP316L welded tubes are specified for:
- Refinery overhead condensers - resisting ammonium chloride and sour water corrosion
- Chemical plant reboilers - handling organic acids and moderate chlorides
- Feedwater heaters - in power generation, where temperature cycling demands fatigue resistance
- Marine heat exchangers - seawater-cooled systems, leveraging Mo content for pitting resistance
- Pulp and paper digesters - in bleaching plant heat recovery
Technical Advantages & Customization
| Feature |
Benefit |
| Low carbon (≤0.035%) |
Eliminates sensitization; weldable without risk of intergranular attack in service |
| Solution annealed weld seam |
Restores full corrosion resistance across the weld zone |
| Tight OD tolerance (±0.10 mm on <25.4 mm) |
Enables efficient tube-to-tubesheet roller expansion—no leakage, no over-rolling |
| Available in U-bend configurations |
Eliminates field welding in bundle assembly; reduces installation time |
| Custom lengths up to 18.3 m |
Minimizes butt-welded joints; reduces potential leak paths |
Customization options:
- OD: 6.0 mm to 219.1 mm (per A249 scope: 1/8″ to 5″ NPS)
- Wall thickness: 0.5 mm to 8.0 mm
- Surface finish: Bright annealed (BA), pickled, or polished
- End preparation: Plain ends, bevelled, or threaded
Frequently Asked Questions (Industry Knowledge Base)
Q: Why specify TP316L over TP304L in heat exchanger tubing?
A: The 2-3% molybdenum content in TP316L significantly enhances resistance to pitting and crevice corrosion in chloride environments. In heat exchangers with cooling water or process streams containing even trace chlorides, TP316L is the minimum recommended grade.
Q: Is welded tube acceptable for U-bundle applications?
A: Yes, provided the weld seam is located on the neutral axis of the bend and the tube is solution annealed. ASTM A249 permits welded tubing for U-bends, and many bundles are fabricated using welded austenitic tubes for cost efficiency and availability in long lengths.
Q: What is the difference between ASTM A249 and ASME SA249?
A: The ASME SA249 specification is adopted by the ASME Boiler and Pressure Vessel Code and is identical in technical requirements to ASTM A249. SA249 is required for components falling under ASME Code jurisdiction (Section VIII, Div. 1). Yuhong supplies both ASTM- and ASME-marked material.
