439 Stainless Steel (UNS S43035)
Ferritic (Ti-stabilized) · ASTM A240/A240M · Density 7.7 g/cm³
Type 439 (UNS S43035) is an 18% chromium ferritic stainless steel stabilized with titanium. It matches 430 in brightness while adding weldability — the stabilization prevents sensitization in the heat-affected zone — and it is immune to chloride stress-corrosion cracking, making it a practical nickel-free alternative to 304 in hot-water and exhaust service.
Chemical Composition (wt%)
| C | Mn | Si | Cr | Ni | Ti | N | P | S |
|---|---|---|---|---|---|---|---|---|
| ≤0.07 | ≤1.00 | ≤1.00 | 17.0–19.0 | ≤0.50 | 0.20+4×(C+N)–1.10 | ≤0.04 | ≤0.040 | ≤0.030 |
Single values are maximums unless a range is shown. Balance: Fe. Per ASTM A240/A240M.
Mechanical Properties
| Tensile strength | ≥415 MPa (60 ksi) |
|---|---|
| Yield strength (0.2%) | ≥205 MPa (30 ksi) |
| Elongation (50 mm) | ≥22% |
| Hardness | ≤89 HRB |
Room-temperature minimum values are summarized for annealed flat product under ASTM A240/A240M unless a condition is named in the property label; product form and thickness can change the requirement.
Physical Properties & Structure
| Density | 7.7 g/cm³ |
|---|---|
| Magnetic response | Magnetic because the room-temperature matrix is ferritic. |
| Microstructure | Ferritic (Ti-stabilized) |
Corrosion Resistance & Limits
- Ferritic grades resist chloride stress-corrosion cracking better than common austenitic grades, while pitting resistance still depends on chromium, molybdenum and exposure.
- Weld condition, section thickness, crevices, deposits and surface contamination can control service performance; validate the actual fabrication and environment.
Fabrication & Heat Treatment
| Welding | Control heat input, interpass temperature and joint design to limit grain growth and loss of toughness; stabilized grades improve but do not remove these controls. |
|---|---|
| Forming | Formability is useful in sheet gauges but lower than common austenitic grades, especially in heavy sections and severe draws. |
| Machining | Machining is generally straightforward with rigid tooling; avoid smearing, overheating and iron contamination of finished surfaces. |
| Heat treatment | Ferritic grades are not hardened by heat treatment. Annealing can restore ductility, but the temperature and cooling route must follow the product specification. |
Equivalent Grades
The closest international equivalents of 439 Stainless Steel are 1.4510 (X3CrTi17) in the EN system, SUS430LX in the JIS system, 022Cr18Ti in the GB system.
These are common corresponding designations, not unconditional substitutes. Verify chemistry, mechanical properties, product standard, delivery condition, dimensions and project approval before changing designation.
| System | Designation |
|---|---|
| UNS | S43035 |
| EN | 1.4510 (X3CrTi17) |
| JIS | SUS430LX |
| GB | 022Cr18Ti |
Reference Product Forms & Dimensional Ranges
Common reference product forms for 439 stainless steel: Coil / Strip, Sheet / Plate, Pipe / Tube.
| Finishes | 2B, 2D, No.4 |
|---|---|
| Sheet / coil thickness | 0.4–3.0 mm |
| Common widths | 1000 / 1219 mm |
Common surface and delivery options: No.1, 2B, BA or mechanically polished finish when supported by the product route; Annealed and pickled, descaled or polished tube finish as specified.
These published ranges are engineering references, not a live-stock or production-capability promise. Confirm the required product form, dimensions, condition, finish and supply route in the quotation.
Typical Applications
- Exhaust system hot-end components
- Heat exchangers and water heaters
- Kitchen sinks and appliance drums
- Solar water-heating panels
- Welded tube for condensers
439 Products We Export
Frequently Asked Questions
What is the difference between 439 and 430 stainless steel?
Same 17–18% chromium family, but 439 adds titanium stabilization and a tighter carbon limit. That means 439 can be welded without losing corrosion resistance next to the weld, while 430 weld zones can sensitize and stain. For unwelded decorative panels 430 is fine; for welded tube or tanks specify 439.
Can 439 replace 304?
Often, yes — in hot water tanks, heat exchangers and exhaust parts 439 resists chlorides comparably and cannot suffer chloride stress-corrosion cracking, a real 304 failure mode in hot water. The trade-offs: ferritic 439 is less ductile for deep drawing and less tough at sub-zero temperatures.
Is 439 magnetic?
Yes. Like all ferritic stainless steels, 439 is strongly attracted to a magnet in every condition. Magnetism says nothing about its corrosion resistance — that comes from the 18% chromium.
Organizational author: Tsingshan (Shandong) Iron & Steel Co., Ltd..Review method, status and limitations.
Other stainless steel grades:
304304L316316L201321310S4104302205202301309S316Ti347904L409L4204414442507303317L254 SMO440C17-4 PH2304
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