Bar and Rod
Plate and Sheet
Strip
Pipe and Tube
Wire
Welding
Powder Material
Cast Products
Forged Products
Fittings
Fastening
Round Bar:
φ2–500 mm, 1–6 m length
Flat/Square Bar:
4–100 mm thickness/width
Hex Bar:
A/F 3–100 mm
Hollow Bar:
OD 20–300 mm
Sheet:
0.3–6 mm thickness
Medium Plate:
6–25 mm thickness
Heavy Plate:
25–100 mm thickness
Standard Strip:
0.05–3 mm thick,
10–600 mm wide
Precision strip:
0.01–0.5 mm thick,
tight tolerance ±0.005 mm
Foil:
0.005–0.1 mm thick
Seamless Tube:
OD 6–450 mm,
WT 1–50 mm,
1–12 m length
Welded Tube:
OD 10–600 mm,
WT 1–20 mm
Capillary Tube:
OD 1–10 mm,
WT 0.1–2 mm
Wire Form:
Cold Drawn Wire,
Bright Wire,
Spring Wire,
Fine Wire,
Ultra-fine Wire
General Diameter:
φ0.1–10 mm
Coil Weight:
50–500 kg,
customizable tolerance
Solid Wire:
φ0.8–4.0 mm
Flux-cored Wire:
φ1.2–4.0 mm
Welding Rod:
φ2.0–5.0 mm
Powder Form:
AM 3D Printing Powder,
Spherical Powder,
Gas-atomized Powder,
Water-atomized Powder
Particle Size:
10–150 μm
Sphericity:
≥90% for AM grade
Cast Ingot:
φ200–800 mm
Precision Casting:
min wall 0.5 mm
Cast Pipe:
OD 100–600 mm,
WT 10–50 mm
Forged Bar:
Φ35–500 mm
Forged Ring:
OD 200–2000 mm
Forging Weight:
1–5000 kg
Fittings Form:
Elbow, Tee, Reducer, Flange, Cap, Outlet, Lap Joint
Size range:
1/2''–24'' (DN15–DN600)
Wall thickness:
Sch10–Sch160, STD, XS, XXS
Pressure Class:
150–2500 LB
Fastening Form:
Bolt, Nut, Screw, Stud, Washer, Pin, Rivet
Metric: M3–M64
Imperial: #4–2.5''
Length: 6–500 mm
430F is a free-machining ferritic straight-chromium stainless steel containing about 17% chromium with a sulphur addition for improved machinability. This datasheet presents the material within the American (ASTM / SAE / UNS) standard system.
With nominally 17% chromium and 0.15% minimum sulphur (plus a small molybdenum addition), 430F is the free-machining version of type 430, developed for high-volume production on automatic lathes and CNC turning centres. The sulphur forms manganese-sulphide inclusions that break chips and improve tool life, at the cost of somewhat reduced corrosion resistance compared with 430. Being ferritic, it is magnetic, offers medium strength and corrosion resistance, and cannot be hardened by heat treatment. It is not recommended for welding because the high sulphur promotes hot cracking.
Typical applications include screw-machine parts, fasteners, shafts, solenoid and valve components, gears, and automotive and pump parts requiring extensive machining.
Typical values, annealed condition.
| Property | Value | Unit |
|---|---|---|
| Density | 7.7 | g/cm³ |
| Melting range | 1425–1510 | °C |
| Elastic modulus | 200 | GPa |
| Coefficient of thermal expansion (20–100 °C) | 10.4 | µm/m·°C |
| Thermal conductivity (100 °C) | 26.1 | W/m·K |
| Specific heat (20 °C) | 460 | J/kg·K |
| Structure | Ferritic | — |
Specified per ASTM A582 (UNS S43020).
| Element | Symbol | Min % | Max % | Role in Alloy |
|---|---|---|---|---|
| Iron | Fe | Balance | — | Base element |
| Chromium | Cr | 16.0 | 18.0 | Corrosion resistance |
| Sulphur | S | 0.15 | — | Free-machining (MnS inclusions) |
| Molybdenum | Mo | — | 0.60 | Offsets sulphur loss of corrosion resistance |
| Manganese | Mn | — | 1.25 | Forms MnS; deoxidiser |
| Silicon | Si | — | 1.00 | Deoxidiser |
| Carbon | C | — | 0.12 | Strength |
| Phosphorus | P | — | 0.060 | Residual impurity |
| Nickel | Ni | — | 0.50 | Residual |
Nominal: 17Cr free-machining (sulphurised) ferritic stainless steel.
Annealed condition, per ASTM A582 for UNS S43020.
| Condition | Property | Value |
|---|---|---|
| Annealed | Tensile strength (UTS) | ~550 MPa |
| Annealed | 0.2% yield strength | ~380 MPa |
| Annealed | Elongation at break | ~25 % |
| Annealed | Hardness | ~262 HB max (cold-drawn higher) |
| — | Elastic modulus | 200 GPa |
Mechanical properties cannot be increased by heat treatment. Confirm against the mill test report.
| Environment | Performance | Notes |
|---|---|---|
| Atmospheric / general | Moderate | Below type 430 (sulphur reduces resistance) |
| Organic and nitric acids | Good | At low concentrations |
| Chloride pitting / crevice | Limited | Sulphide inclusions are initiation sites |
| Chloride stress-corrosion cracking | Very Good | Ferritic — largely immune |
| Seawater | Not recommended | — |
Corrosion resistance is moderate and below that of type 430; the molybdenum addition partly offsets the loss caused by the sulphur. Best resistance is obtained with a smooth, passivated surface.
A ferritic free-machining grade; cannot be hardened by heat treatment. Properties are set by annealing.
Anneal Heat to 677–760 °C and air cool (or slow cool). Avoid prolonged exposure in the 400–540 °C range (475 °C embrittlement) and high-temperature soaking that promotes grain growth.
Not recommended for welding — the high sulphur content promotes hot cracking. Where joining is unavoidable, use low heat input and an austenitic filler; results are inferior to non-free-machining ferritics.
| Welding Process | Applicability | Filler / Consumable |
|---|---|---|
| GTAW / TIG | Not recommended | Austenitic (309) if unavoidable |
| GMAW / MIG | Not recommended | — |
| Brazing | Preferred join method | — |
The free-machining sulphur addition makes this grade unsuitable for structural welding.
Machining Guidelines
| Parameter | Recommendation |
|---|---|
| Machinability | Excellent — one of the most machinable stainless steels |
| Chip breaking | MnS inclusions break chips; high speeds and feeds possible |
| Tooling | Standard carbide or HSS; good tool life |
| Coolant | Ample flood coolant |
Forming Processes
| Process | Notes |
|---|---|
| Cold forming | Limited — sulphur reduces ductility |
| Hot forming | ~1100–800 °C; anneal afterward |
| Industry | Typical Components | Key Requirements |
|---|---|---|
| Screw machining | Fasteners, shafts, fittings, nuts | Extensive machining |
| Automotive | Solenoid and valve parts, pump components | Machinability + moderate corrosion resistance |
| Electrical | Solenoid cores, magnetic parts | Ferritic magnetic response |
| General industrial | Gears, studs, machined hardware | Machinability + cost |
| Product Form | ASTM Standard | SAE / Other |
|---|---|---|
| Bar and wire | ASTM A582 | SAE J405 (51430F) |
| Bar (cold-finished) | ASTM A581 | — |
| Rod, bar and shapes | ASTM A276 | — |
| Forging stock | ASTM A314 | — |
Free-machining (sulphurised) ferritic stainless steel. UNS S43020.
| Grade | Cr % | S % | Mo % | Best Used For |
|---|---|---|---|---|
| 430F | 16–18 | ≥0.15 | ≤0.60 | Free-machining ferritic; screw-machine parts |
| 430 | 16–18 | ≤0.030 | — | General ferritic; non-free-machining |
| 416 | 12–14 | ≥0.15 | ≤0.60 | Free-machining martensitic |
| 303 | 17–19 | ≥0.15 | — | Free-machining austenitic |
| 434 | 16–18 | ≤0.030 | 0.75–1.25 | Mo-bearing ferritic; outdoor |
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