ASME SA240 439 Stainless Steel Plate | SA240 Type 439
What is ASME SA240 439 Stainless Steel Plate?
As a professional stainless steel plate supplier and China Mill-Direct Supply / Mill Direct Exporter, SHH STEEL is pleased to present ASME SA240 439 Stainless Steel Plate, also known as SA240 Type 439.
ASME SA240 Type 439 is a titanium-stabilized ferritic stainless steel containing approximately 17–19% chromium. The addition of titanium stabilizes carbon and nitrogen, effectively preventing intergranular corrosion after welding and improving overall corrosion performance compared with unstabilized Type 430. Type 439 offers good resistance to atmospheric corrosion, fresh water, and many mild chemical environments, together with excellent oxidation resistance at elevated temperatures.
As a ferritic grade, Type 439 is magnetic, non-hardenable by heat treatment, and provides good formability. It is widely used in automotive exhaust systems, heat exchangers, furnace components, and other applications where better weldability and corrosion resistance than standard 430 are required, while remaining more economical than austenitic grades such as 304.
SHH STEEL supplies ASME SA240 439 as true Mill Direct Supply, sourcing directly from major Chinese stainless steel mills. This model delivers competitive mill pricing, consistent quality, full heat traceability and shorter lead times. We offer a practical dimensional range and a selection of surface finishes to meet project requirements.
Material Specification
| Specification Element | Requirement | SHH STEEL Compliance |
|---|---|---|
| Primary Standard | ASME SA240 / SA240M | Full compliance |
| Steel Grade | Type 439 (UNS S43035) | Confirmed |
| Product Form | Plate, Sheet, Coil | Available |
| Delivery Condition | Annealed | Standard |
| Thickness Range | 0.5 mm – 50 mm (thicker available on request) | Custom sizes supported |
| Width | Up to 1500–2000 mm (wider on request) | Available |
| Length | Up to 6000 mm or cut-to-length / coil | Available |
| Surface Finish | 2B, BA, No.1, No.4, and others on request | Available |
| Certification | EN 10204 3.1 / ASME Mill Test Certificate | Available |
Chemical Composition
Heat Analysis (Ladle Analysis) according to ASME SA240 Type 439:
| Element | Content (%) |
|---|---|
| Carbon (C) | ≤ 0.030 |
| Silicon (Si) | ≤ 1.00 |
| Manganese (Mn) | ≤ 1.00 |
| Phosphorus (P) | ≤ 0.040 |
| Sulfur (S) | ≤ 0.030 |
| Chromium (Cr) | 17.00 – 19.00 |
| Nickel (Ni) | ≤ 0.50 |
| Titanium (Ti) | ≥ 0.20 + 4 × (C + N) |
| Nitrogen (N) | ≤ 0.030 |
| Iron (Fe) | Balance |
Product Analysis (typical permissible variations):
| Element | Content (%) |
|---|---|
| Carbon (C) | ≤ 0.030 |
| Silicon (Si) | ≤ 1.00 |
| Manganese (Mn) | ≤ 1.00 |
| Phosphorus (P) | ≤ 0.040 |
| Sulfur (S) | ≤ 0.030 |
| Chromium (Cr) | 16.90 – 19.10 |
| Nickel (Ni) | ≤ 0.50 |
| Titanium (Ti) | ≥ 0.20 + 4 × (C + N) |
| Nitrogen (N) | ≤ 0.030 |
The titanium stabilization (minimum Ti content related to carbon + nitrogen) is the defining feature of Type 439. It prevents chromium carbide/nitride precipitation and provides excellent resistance to intergranular corrosion after welding.
Mechanical Properties
Annealed Condition (typical)
| Property | Value |
|---|---|
| Tensile Strength | ≥ 415 MPa (60 ksi) |
| Yield Strength (0.2%) | ≥ 205 MPa (30 ksi) |
| Elongation (in 50 mm) | ≥ 22% |
| Hardness | ≤ 183 HB |
Physical Properties
- Density: approximately 7.70 g/cm³
- Magnetic: Magnetic in all conditions
- Melting Range: approximately 1425–1510°C
Type 439 cannot be hardened by quenching and tempering. Strength is obtained in the annealed condition, with possible moderate increases through cold working.
Material Comparison
| Grade | Structure | Stabilization | Key Advantage | Typical Preference |
|---|---|---|---|---|
| SA240 Type 430 | Ferritic | None | Economical, good formability | General ferritic applications |
| SA240 Type 439 | Ferritic | Titanium | Improved weldability & intergranular corrosion resistance | Automotive exhaust, welded ferritic service |
| SA240 Type 441 | Ferritic | Nb + Ti | Higher strength & temperature capability | More demanding exhaust systems |
| SA240 Type 304 | Austenitic | None | Excellent corrosion resistance & formability | General corrosive service |
| SA240 Type 410S | Martensitic | Low carbon | Heat-treatable with improved weldability | Strength + moderate corrosion |
ASME SA240 439 is the preferred upgrade from standard 430 when welding is involved or when better resistance to intergranular corrosion is required. It is widely used in automotive exhaust systems as a cost-effective alternative to austenitic grades. For higher temperature or strength requirements in exhaust applications, stabilized grades such as 441 are often considered. For maximum corrosion resistance, astm a240 type 304 stainless steel sheet plate remains the common choice.
Corrosion Resistance
ASME SA240 Type 439 offers good resistance to atmospheric corrosion, fresh water, and many mild chemical environments — generally better than unstabilized Type 430, especially after welding. The titanium stabilization provides excellent resistance to intergranular corrosion.
It also delivers very good oxidation resistance at elevated temperatures, making it suitable for exhaust and heat-resistant applications. It is not recommended for severe chloride environments (seawater) or strong reducing acids, where austenitic or duplex grades should be selected.
Weldability
ASME SA240 Type 439 has significantly improved weldability compared with standard Type 430 due to titanium stabilization. The risk of intergranular corrosion in the heat-affected zone is greatly reduced.
Low heat input and proper joint design are still recommended to control grain growth. Matching or suitable ferritic/austenitic filler metals can be used depending on the application. Overall, Type 439 is one of the more weldable standard ferritic stainless steels.
Heat Treatment
Type 439 is a ferritic stainless steel and cannot be hardened by quenching and tempering.
Annealing
- Temperature: typically 760 – 850°C
- Cooling: Air cool or furnace cool
Annealing is performed to relieve stresses after cold working or welding, restore ductility, and optimize corrosion resistance. Excessive grain growth should be avoided by controlling time at temperature.
Surface Finishes
| Finish | Description | Typical Use / Keywords |
|---|---|---|
| 2B | Cold-rolled, annealed, pickled, skin-passed | SA240 439 2B – most common for general fabrication |
| BA | Bright Annealed | SA240 439 BA – decorative and clean applications |
| No.1 | Hot-rolled, annealed and pickled | SA240 439 No.1 – industrial plate |
| No.4 | Brushed finish | SA240 439 No.4 – when improved surface appearance is required |
| Special | Ground or custom finishes | SA240 439 Special – on request |
SHH STEEL regularly supplies ASME SA240 439 in 2B and No.1 finishes, and can provide other finishes according to project requirements.
Tolerances
Dimensional tolerances for ASME SA240 439 Stainless Steel Plate conform to ASME SA240 and the general requirements of ASTM A480.
Typical available size range for SA240 439 plate/sheet:
- Thickness: 0.5 mm – 50 mm (thicker plates available on request)
- Width: up to 1500–2000 mm (wider on request)
- Length: up to 6000 mm or supplied in coil / cut-to-length
Thickness, width, length and flatness tolerances are controlled within standard limits. Tighter tolerances for SA240 439 plate can be arranged for specific project needs. SHH STEEL provides precise dimensional control for both standard and custom-size SA240 439 material.
Equivalent Material Grades
| Grade / Designation | Standard | Notes |
|---|---|---|
| SA240 Type 439 | ASME SA240 | — |
| A240 Type 439 | ASTM A240 | Essentially identical |
| UNS S43035 | — | Unified Numbering System |
| 1.4510 / X3CrTi17 | EN 10088-2 | European equivalent |
| SUS430LX / related | JIS | Japanese related stabilized grades |
| Related Ti-stabilized 430 | GB/T | Chinese approximate equivalents |
Related grades frequently evaluated with ASME SA240 439 include astm a240 type 430 stainless steel sheet plate, astm a240 type 441 stainless steel sheet plate, astm a240 type 304 stainless steel sheet plate, and astm a240 type 409 stainless steel sheet plate.
Applications
ASME SA240 Type 439 is widely used in applications requiring improved weldability and corrosion resistance over standard 430. Typical applications of SA240 439 include:
| Industry / Sector | Typical Components / Equipment (with keywords) |
|---|---|
| Automotive Exhaust | SA240 439 exhaust pipes, mufflers, catalytic converter shells |
| Heat Exchangers | SA240 439 heat exchanger tubes and components |
| Furnace & Heat Treatment | SA240 439 furnace parts and heat-resistant components |
| Chemical Processing | SA240 439 equipment in mild to moderate corrosive service |
| Appliances & Kitchen | SA240 439 panels and components requiring better weldability |
| General Fabrication | SA240 439 welded and formed structures |
| Industrial Equipment | SA240 439 parts needing oxidation resistance and weldability |
Why Choose SHH STEEL
SHH STEEL is a China Mill-Direct Supply and Mill Direct Exporter of stainless steel plate. We maintain long-term strategic cooperation with major Chinese stainless steel mills and supply ASME SA240 Type 439 with the following advantages:
- Competitive mill-direct pricing
- Consistent quality and complete heat traceability
- Full Mill Test Certificates (EN 10204 3.1 / ASME)
- Flexible dimensions and surface finishes (including SA240 439 2B and SA240 439 No.1)
- Technical support for stabilized ferritic material selection
- Reliable worldwide logistics and export documentation
FAQ
- What is the main advantage of SA240 439 over SA240 430?Type 439 is titanium-stabilized, providing significantly better resistance to intergranular corrosion after welding and improved overall corrosion performance. SHH STEEL recommends 439 when welding is required or when better corrosion resistance than standard 430 is needed.
- Is ASME SA240 439 magnetic?Yes, Type 439 is magnetic in all conditions. SHH STEEL supplies material that meets this characteristic.
- Can SA240 439 be hardened by heat treatment?No. As a ferritic stainless steel, it cannot be hardened by quenching and tempering. SHH STEEL supplies material in the annealed condition as standard.
- What is the density of SA240 Type 439?Approximately 7.70 g/cm³. SHH STEEL provides material certificates confirming physical and mechanical properties.
- Can SHH STEEL supply dual-certified ASME SA240 / ASTM A240 Type 439?Yes, SHH STEEL commonly supplies dual-certified ASME SA240 / ASTM A240 Type 439 material.
Conclusion
ASME SA240 439 Stainless Steel Plate (SA240 Type 439) is a titanium-stabilized ferritic stainless steel that offers improved weldability, better resistance to intergranular corrosion, and good overall corrosion and oxidation resistance compared with standard Type 430. It is a cost-effective and reliable choice for automotive exhaust systems, heat exchangers, and many welded ferritic applications.
As a professional China Mill-Direct Supply and Mill Direct Exporter, SHH STEEL provides high-quality ASME SA240 Type 439 plate with competitive pricing, full certification and complete technical support.
Contact SHH STEEL today for stock availability, surface finish options (including SA240 439 2B and SA240 439 No.1), or a competitive quotation.
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