ASTM A199 Seamless Alloy-Steel Heat-Exchanger Tubes
ASTM A199 covers seamless cold-drawn alloy-steel tubes for heat exchangers, condensers, and similar heat transfer equipment. This specification includes multiple grades of chromium-molybdenum alloy steels for elevated temperature service.
Key Features
| Feature | Description |
|---|---|
| Material | Alloy Steel (Chromium-Molybdenum types) |
| Process | Cold-Drawn Seamless |
| Primary Use | Heat exchangers for elevated temperatures |
| Key Property | Enhanced high-temperature strength & corrosion resistance |
Available Grades
| Grade | Alloy Composition | Similar To | Max Service Temp |
|---|---|---|---|
| T5 | 5% Cr - 0.5% Mo | A213 T5 | ~600°C (1110°F) |
| T5b | 5% Cr - 0.5% Mo (Special) | - | ~600°C |
| T7 | 7% Cr - 0.5% Mo | - | ~650°C (1200°F) |
| T9 | 9% Cr - 1% Mo | A213 T9 | ~650°C |
| T11 | 1¼% Cr - 0.5% Mo | A213 T11 | ~525°C (975°F) |
| T22 | 2¼% Cr - 1% Mo | A213 T22 | ~575°C (1065°F) |
Chemical Composition (Example: T11)
| Element | Composition (%) |
|---|---|
| Carbon (C) | 0.05 - 0.15 |
| Manganese (Mn) | 0.30 - 0.60 |
| Phosphorus (P), max | 0.025 |
| Sulfur (S), max | 0.025 |
| Silicon (Si) | 0.50 - 1.00 |
| Chromium (Cr) | 1.00 - 1.50 |
| Molybdenum (Mo) | 0.44 - 0.65 |
Mechanical Properties (Example: T11)
| Property | Requirement |
|---|---|
| Tensile Strength, min | 415 MPa (60,000 psi) |
| Yield Strength, min | 205 MPa (30,000 psi) |
| Elongation, min | 30% |
| Hardness, max | Typically ≤ 163 HB |
Manufacturing Process
Production Sequence:
Seamless tube making (hot-rolled)
Cold drawing (for dimensional accuracy)
Heat treatment (normalized & tempered or annealed)
Final processing (straightening, cutting)
Cold Drawing Benefits:
Tighter tolerances for tube-to-tubesheet fit
Smoother surface for better heat transfer
Improved mechanical properties
Applications
High-Temperature Heat Exchangers:
Refinery heat exchangers (crude, vacuum, catalytic)
Chemical process heaters
Waste heat recovery units
High-temperature feedwater heaters
Typical Service Conditions:
Temperature: 400-650°C (750-1200°F)
Pressure: High-pressure service
Media: Hydrocarbons, steam, process fluids
Why Choose A199 over Carbon Steel?
Advantages over A179/A192:
Higher temperature capability (up to 650°C vs 400°C)
Better oxidation resistance (chromium content)
Superior creep strength at elevated temperatures
Enhanced corrosion resistance in certain environments
Grade Selection Guide:
| Service Temperature | Recommended Grade |
|---|---|
| < 400°C (750°F) | A179/A192 (carbon steel) |
| 400-525°C (750-975°F) | T11 |
| 525-575°C (975-1065°F) | T22 |
| 575-650°C (1065-1200°F) | T5/T7/T9 |
Heat Treatment Requirements
Mandatory Heat Treatment:
Normalized & Tempered (most common)
Annealed (for certain applications)
Solution annealed (for austenitic grades if included)
Purpose:
Optimize microstructure for service conditions
Relieve stresses from cold drawing
Achieve specified mechanical properties
Testing Requirements
| Test | Requirement |
|---|---|
| Hydrostatic Test | Mandatory (every tube) |
| Tensile Test | Per heat treat lot |
| Flattening Test | Required |
| Flaring Test | Required |
| Hardness Test | Optional (often specified) |
| Grain Size | For certain grades |
Comparison with Related Standards
| Standard | Key Difference from A199 |
|---|---|
| ASTM A213 | Hot-finished alloy-steel tubes |
| ASTM A179 | Carbon steel for moderate temperatures |
| ASTM A269 | Stainless steel for corrosive service |
| ASTM A334 | Alloy steel for low-temperature service |
Ordering Information
Typical Specification:
text
ASTM A199 T11 Tubes 25.4 mm OD × 2.11 mm Wall × 6,000 mm Length Normalized & tempered For refinery heat exchanger service
Required Information:
ASTM A199
Grade (T5, T11, T22, etc.)
Dimensions (OD × Wall × Length)
Heat treatment condition
Testing requirements
End preparation
Important Notes
⚠️ Not for General Piping:
A199 is for heat exchanger TUBES, not fluid transport piping
Use A335 for high-temperature alloy steel piping
Tube vs Pipe: Different dimensional standards and applications
Fabrication Considerations:
Welding requires care (preheat, low-hydrogen electrodes)
Post-weld heat treatment often required
Tube expanding into tubesheets standard practice
U-bend capabilities available
International Equivalents
| Region | Equivalent Standard | Notes |
|---|---|---|
| Europe | EN 10216-2 | Various alloy steel grades |
| Japan | JIS G3463 | Alloy steel heat exchanger tubes |
| China | GB 5310 | Alloy steel boiler tubes |
In summary: ASTM A199 specifies cold-drawn seamless alloy-steel tubes for high-temperature heat exchanger applications where carbon steels (A179/A192) are inadequate. Its chromium-molybdenum alloy grades provide enhanced strength, oxidation resistance, and temperature capability for demanding process heat transfer equipment in refineries, chemical plants, and power generation facilities.
