AISI 439 Stainless Steel Plate | A240 Type 439 | UNS S43035
What is AISI 439 Stainless Steel?
As a professional China steel mill-Direct Supply and stainless steel plate supplier, SHH STEEL is pleased to present AISI 439 Stainless Steel Plate.
AISI 439 is widely known and searched under many different names and designations, including AISI 439, ASTM A240 Type 439, ASME SA240 Type 439, UNS S43035, 439 stainless steel, 439 stainless steel plate, 1.4510, X3CrTi17, SUS430LX related and titanium-stabilized 430. All these names refer to the same titanium-stabilized 17–19% chromium ferritic stainless steel.
AISI 439 contains higher chromium than A240 430 plus intentional titanium. Titanium combines with carbon and nitrogen, reducing the risk of intergranular corrosion after welding and improving oxidation resistance in exhaust and heat-exchanger service. The grade remains magnetic, non-hardenable by conventional quench and temper, and is normally supplied annealed.
Typical uses include automotive exhaust systems, heat shields, water-heater tanks, heat exchangers and welded ferritic fabrications that need better performance than 430 without the cost of 304.
SHH STEEL supplies AISI 439 as true China steel mill-Direct Supply, sourcing directly from major Chinese stainless steel mills. This model delivers competitive mill pricing, consistent quality, complete heat traceability and reliable delivery.
AISI 439 is frequently compared with A240 430, A240 409, A240 441, A240 434, A240 444 and A240 436. SHH STEEL provides technical support to help customers choose the most appropriate 400-series grade.
Material Specification
| Specification Element | Requirement | SHH STEEL Compliance |
|---|---|---|
| Grade | AISI 439 / A240 Type 439 / UNS S43035 | Confirmed |
| Related Standards | ASTM A240, ASME SA240, EN 1.4510, JIS related | Available |
| Product Form | Plate, Sheet | Available |
| Delivery Condition | Annealed | Standard |
| Thickness Range | 0.4 mm – 50 mm (thicker available on request) | Custom sizes supported |
| Width | Up to 1500–2000 mm | Available |
| Length | Up to 6000–12000 mm or coil / cut-to-length | Available |
| Surface Finish | 2B, 2D, No.1, BA | Available |
| Certification | EN 10204 3.1 / Mill Test Certificate | Available |
SHH STEEL can supply dual-certified ASTM A240 / ASME SA240 Type 439 material when required by the project.
Chemical Composition
Typical Chemical Composition of AISI 439 (UNS S43035):
| Element | Content (%) |
|---|---|
| Carbon (C) | ≤ 0.07 |
| 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) min – 1.10 max |
| Nitrogen (N) | ≤ 0.040 |
| Aluminum (Al) | ≤ 0.15 |
| Iron (Fe) | Balance |
The defining features of AISI 439 are 17–19% chromium and titanium stabilization. Higher chromium improves oxidation and general corrosion resistance versus 430 and 409. Titanium ties up carbon and nitrogen so welded joints remain resistant to intergranular attack. SHH STEEL carefully controls the titanium-to-carbon ratio to keep AISI 439 weldable and stable.
Mechanical Properties
Annealed Condition (typical ASTM A240 values)
| Property | Value |
|---|---|
| Tensile Strength | ≥ 415 MPa (60 ksi) |
| Yield Strength (0.2%) | ≥ 205 MPa (30 ksi) |
| Elongation (in 50 mm) | ≥ 22% |
| Hardness | ≤ 183 HBW / 89 HRBW |
AISI 439 is supplied annealed, with good ductility for forming and welding. It is magnetic and cannot be hardened by conventional quench and temper. SHH STEEL supplies AISI 439 meeting A240 mechanical limits.
Physical Properties
Density is approximately 7.70 g/cm³. Melting range is approximately 1425–1510°C.
Material Comparison
| Grade | UNS | Cr (%) | Stabilization | Typical Preference |
|---|---|---|---|---|
| AISI 409 | S40900 | 10.5–11.75 | Titanium | Economy exhaust systems |
| AISI 430 | S43000 | 16.0–18.0 | None | Appliances and indoor trim |
| AISI 439 | S43035 | 17.0–19.0 | Titanium | Welded exhaust / water heaters |
| AISI 441 | S43932 | 17.5–18.5 | Nb + Ti | Higher-temperature exhaust |
| AISI 434 | S43400 | 16.0–18.0 | Molybdenum | Automotive trim / mild chlorides |
| AISI 444 | S44400 | 17.5–19.5 | Mo + Ti/Nb | Water tanks / higher chloride ferritic |
AISI 439 is selected when welded ferritic performance must be better than A240 430 and oxidation resistance must be better than A240 409. For higher exhaust-temperature strength, SHH STEEL recommends A240 441. For better chloride resistance in tanks, compare with A240 444.
Corrosion Resistance
AISI 439 offers good resistance to atmosphere, fresh water, exhaust condensate and many household or process environments. Titanium stabilization protects welded joints from intergranular corrosion. Higher chromium gives better oxidation resistance than 409 and better general corrosion resistance than unstabilized 430 in many welded applications.
It is not equivalent to a240 304 or a240 316l in aggressive chloride service. For more severe ferritic chloride duty, SHH STEEL recommends A240 444.
Weldability
AISI 439 has good weldability for a ferritic stainless steel because of titanium stabilization and relatively low carbon. Matching 439 or 409/430-type filler metals are commonly used for exhaust and tank fabrications.
Heat input should be controlled to limit grain growth in the heat-affected zone. Post-weld annealing is generally not required for most applications. SHH STEEL recommends proper welding procedures and post-weld cleaning.
Heat Treatment
AISI 439 is normally supplied in the annealed condition by SHH STEEL.
Annealing restores ductility after cold forming and optimizes corrosion resistance. The grade cannot be hardened by conventional quench and temper. SHH STEEL controls heat treatment so AISI 439 remains formable and weldable.
Surface Finishes
| Finish | Description | Typical Use / Keywords |
|---|---|---|
| 2B | Cold-rolled, annealed, pickled, skin-passed | AISI 439 2B – most common for sheet and thin plate |
| 2D | Cold-rolled, annealed and pickled | AISI 439 2D – forming and exhaust stampings |
| No.1 | Hot-rolled, annealed and pickled | AISI 439 No.1 / A240 439 No.1 – industrial plate |
| BA | Bright Annealed | AISI 439 BA – cleaner surface applications |
SHH STEEL regularly supplies AISI 439 in 2B, 2D and No.1 finishes for exhaust and fabrication use.
Tolerances
Dimensional tolerances for AISI 439 Stainless Steel Plate supplied by SHH STEEL generally conform to ASTM A480 practices.
Typical available size range is thickness 0.4 mm – 50 mm, width up to 1500–2000 mm, and length up to 6000–12000 mm or coil/cut-to-length. SHH STEEL provides precise dimensional control and can support tighter tolerances when required.
Equivalent Material Grades
| Grade / Designation | Standard / Region | Notes |
|---|---|---|
| AISI 439 | AISI | Main commercial keyword |
| A240 Type 439 | ASTM A240 / ASME SA240 | Plate specification |
| UNS S43035 | Unified Numbering System | Primary UNS designation |
| 1.4510 / X3CrTi17 | EN (Europe) | European equivalent |
| SUS430LX related | JIS (Japan) | Japanese related grade |
| Related 10Cr17Ti | GB/T (China) | Chinese related grade |
| Related 409 / 430 / 441 | Multiple | Nearby ferritic variants |
Related grades for comparison include A240 430, A240 409, A240 441, A240 434, A240 444 and A240 436.
Applications
AISI 439 is selected for welded ferritic fabrications that need better oxidation and corrosion resistance than 430 or 409. Typical applications of AISI 439 include:
| Industry / Sector | Typical Components / Equipment (with keywords) |
|---|---|
| Automotive Exhaust | AISI 439 exhaust pipes, mufflers, converter shells and resonators |
| Automotive Heat Management | AISI 439 heat shields and stamped high-temperature parts |
| Water Heaters & Tanks | AISI 439 inner tanks and welded tank components |
| Heat Exchangers | AISI 439 shells, plates and fabricated heat-transfer parts |
| General Fabrication | AISI 439 covers, housings and welded structures |
| Industrial Equipment | A240 Type 439 No.1 plate for welded ferritic constructions |
SHH STEEL supplies AISI 439 for these exhaust and welded applications with consistent quality. For related industry solutions, see our equipment manufacturing, energy industry and machinery industry pages. Supporting services include steel cutting services, steel welding services and steel bending and forming services.
Why Choose SHH STEEL
SHH STEEL is a China steel mill-Direct Supply specializing in stainless steel plate and sheet. By working directly with major Chinese stainless steel mills, SHH STEEL supplies AISI 439 with the following advantages:
- Genuine China steel mill-Direct Supply pricing
- Consistent quality and complete heat traceability
- Full Mill Test Certificates (EN 10204 3.1)
- Titanium-stabilized AISI 439 material optimized for exhaust and welded service
- Flexible dimensions and surface finishes (including AISI 439 2B, AISI 439 2D and AISI 439 No.1)
- Technical support for selection among AISI 409, 430, 439, 441 and 444
- Value-added services including steel cutting services, steel welding services, steel bending and forming services and worldwide shipping service
For more information about our company and full product range, please visit China steel Mill Agent-SHH STEEL.
FAQ
- What are the other common names for AISI 439?AISI 439 is also known as ASTM A240 Type 439, UNS S43035, 1.4510, X3CrTi17 and titanium-stabilized 430. SHH STEEL can certify the required designation.
- What is the difference between AISI 439 and AISI 430?AISI 439 has higher chromium and titanium stabilization, so it welds better and resists oxidation and intergranular corrosion better than 430. SHH STEEL recommends 439 for exhaust and welded tanks.
- What is the difference between AISI 439 and AISI 409?Both are titanium-stabilized ferritics. AISI 439 has much higher chromium (17–19% vs about 11%), giving better corrosion and oxidation resistance. SHH STEEL recommends 409 for economy exhaust and 439 for higher-performance systems.
- Is AISI 439 magnetic?Yes. AISI 439 is ferritic and remains magnetic in the annealed condition.
- What is the density of AISI 439?Approximately 7.70 g/cm³. SHH STEEL provides mill certificates confirming chemistry and mechanical properties.
- Can AISI 439 replace 304?In many exhaust and tank applications yes, at lower nickel cost. For aggressive chlorides, SHH STEEL still recommends 304 or 316L.
- Does SHH STEEL supply dual-certified ASTM A240 Type 439 / AISI 439 material?Yes, SHH STEEL commonly supplies dual-certified material upon request.
Conclusion
AISI 439 Stainless Steel Plate is a titanium-stabilized 17–19% chromium ferritic grade designed for welded exhaust systems, water heaters and heat-resistant fabrications. It offers a practical upgrade from 409 and 430 when oxidation resistance, weldability and cost must be balanced.
As a professional China steel mill-Direct Supply, SHH STEEL provides high-quality AISI 439 Stainless Steel Plate with competitive pricing, full certification and complete technical support.
Contact SHH STEEL today for stock availability, surface finish options (including AISI 439 2B, AISI 439 2D and AISI 439 No.1), or a competitive quotation.
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