Description
ASTM A450 TP409 TP430 TP443 TP439 TP436 Cold Drawn Steel Tubes
General Requirements
ASTM A450 specifies the requirements for cold drawn stainless steel tubing. This standard covers several steel grades, including TP409, TP430, TP443, TP439, and TP436. These tubes are manufactured through cold drawing, which enhances mechanical properties and surface finish while maintaining dimensional accuracy. The tubes are suitable for applications where corrosion resistance and strength are critical, and general use in mechanical and structural components.
Material
The ASTM A450 standard includes ferritic stainless steel grades:
- TP409: Basic ferritic stainless steel with good corrosion resistance
- TP430: Popular ferritic grade with improved corrosion resistance and formability
- TP443: High chromium ferritic steel with excellent stress corrosion crack resistance
- TP439: Stabilized grade with titanium addition for improved resistance to intergranular corrosion
- TP436: Stabilized grade with niobium addition for high-temperature corrosion resistance
All materials are furnished as cold drawn tubes, ensuring enhanced mechanical properties and surface finishing suitable for demanding applications.
Specification
- Standard: ASTM A450
- Process: Cold drawn
- Shape: Tubes (round, generally), measured by outer diameter (OD) and wall thickness (WT)
- Surface finish: Cold-drawn finish with consistent dimensional tolerances
- Heat Treatment: Typically annealed after cold drawing, unless otherwise specified
Key Features
- Excellent corrosion resistance in oxidizing environments
- High strength and toughness due to cold drawing process
- Good weldability and formability, especially for grades like TP430
- Resistance to stress corrosion cracking in certain grades (TP443)
- Stabilization against chromium carbide precipitation (TP439, TP436)
- Dimensional accuracy and surface finish ideal for precision applications
Chemical Composition
| Grade | C (max) | Mn (max) | Si (max) | P (max) | S (max) | Cr (%) | Ni (%) | Ti (max) | Nb (max) | Other Elements |
|---|---|---|---|---|---|---|---|---|---|---|
| TP409 | 0.08 | 1.00 | 1.00 | 0.040 | 0.030 | 10.5–11.75 | 0.50 max | – | – | Trace N |
| TP430 | 0.12 | 1.00 | 1.00 | 0.040 | 0.030 | 16.0–18.0 | 0.75 max | – | – | – |
| TP443 | 0.030 | 1.00 | 1.00 | 0.040 | 0.030 | 16.0–18.0 | 0.75 max | – | – | Nb 0.75 max |
| TP439 | 0.030 | 1.00 | 1.00 | 0.040 | 0.030 | 17.0–19.0 | 0.75 max | 6xC max | – | Ti to stabilize carbide |
| TP436 | 0.030 | 1.00 | 1.00 | 0.040 | 0.030 | 15.0–18.0 | 0.75 max | – | 6xC max | Nb to stabilize carbide |
Mechanical Properties
| Grade | Tensile Strength (MPa) | Yield Strength (MPa) | Elongation (%) | Hardness (HV) |
|---|---|---|---|---|
| TP409 | 415 min | 205 min | 20 min | 160 max |
| TP430 | 450 min | 205 min | 18 min | 160 max |
| TP443 | 450 min | 205 min | 18 min | 200 max |
| TP439 | 450 min | 205 min | 18 min | 200 max |
| TP436 | 450 min | 205 min | 18 min | 200 max |
Steel Grade Summary
| Steel Grade | Description | Notable Features |
|---|---|---|
| TP409 | Basic ferritic stainless steel | Good corrosion resistance, economical |
| TP430 | General-purpose ferritic stainless steel | Better corrosion resistance, weldable |
| TP443 | High chromium ferritic stainless steel | Excellent stress corrosion cracking resistance |
| TP439 | Titanium stabilized ferritic stainless steel | Resistance to intergranular corrosion |
| TP436 | Niobium stabilized ferritic stainless steel | High-temperature corrosion resistance |
Application
Cold drawn ASTM A450 ferritic stainless steel tubes have a wide range of applications including:
- Automotive exhaust systems
- Heat exchangers and boiler tubes
- Structural components and architectural applications
- Chemical and petrochemical process equipment
- HVAC systems and commercial refrigeration
- General mechanical tubing requiring corrosion resistance and dimensional precision
Equivalent Grades
| ASTM A450 Grade | EN / DIN Equivalent | UNS Number | JIS Equivalent |
|---|---|---|---|
| TP409 | EN 1.4512 (409) | S40900 | SUS409 |
| TP430 | EN 1.4016 (430) | S43000 | SUS430 |
| TP443 | EN 1.4529 (443) | S44300 | SUS443 |
| TP439 | EN 1.4517 (439) | S43932 | SUS439 |
| TP436 | EN 1.4521 (436) | S43600 | SUS436 |
