What Is SUS430 Stainless Steel? Grade Guide and Uses
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What Is SUS430 Stainless Steel?
SUS430 is the JIS G4303 / G4305 designation for a ferritic stainless steel with 16–18% chromium and no intentional nickel addition. The Chinese national-standard counterpart is 1Cr17 (GB/T 1220) or 10Cr17, and the international equivalents are AISI 430, UNS S43000 and EN 1.4016 (X6Cr17). Because it contains no nickel, SUS430 is often called 18-0 stainless steel, contrasting with the 18-8 (304) and 18-10 (316) austenitic families.
The absence of nickel changes nearly every engineering decision: the grade is ferromagnetic, costs less than austenitic grades, and relies entirely on chromium for corrosion protection. In the annealed condition SUS430 delivers a minimum tensile strength of 450 MPa, yield strength of 205 MPa, elongation of 22% and hardness up to 183 HB.
Chemical Composition and Key Properties
| Item | Value |
|---|---|
| Chromium (Cr) | 16.0 – 18.0% |
| Carbon (C) | ≤ 0.12% |
| Nickel (Ni) | Not added (trace only) |
| Manganese (Mn) / Silicon (Si) | ≤ 1.0% each |
| Tensile strength (annealed) | ≥ 450 MPa |
| Yield strength | ≥ 205 MPa |
| Elongation | ≥ 22% |
| Hardness | ≤ 183 HB |
| Magnetism | Ferromagnetic |
Corrosion resistance is good in nitric acid, organic acids and atmospheric exposure, but weak against pitting and chloride-ion attack. SUS430 cannot be hardened by heat treatment; cold working raises strength and hardness while reducing ductility.
SUS430F vs SUS430FR
Two important variants appear in JIS supply:
SUS430F adds 0.15–0.30% sulfur to improve machinability for high-speed automatic lathe production of fasteners, nuts and gears. Weldability is poor because of the high sulfur.
SUS430FR holds sulfur at 0.08–0.15% and is processed for low coercivity, giving significant soft-magnetic behavior. It is used for electromagnetic components such as relay parts, solenoid cores and motor laminations.
A further variant, 430LX, adds titanium or niobium with reduced carbon to restore weldability and formability; it is common in hot water tanks and sanitary ware.
Equivalent Standards
| System | Designation |
|---|---|
| JIS (Japan) | SUS430 |
| AISI / UNS (USA) | 430 / S43000 |
| EN (Europe) | 1.4016 / X6Cr17 |
| GB (China) | 1Cr17 / 10Cr17 |
Comparison with SUS304 and SUS410
| Grade | Family | Corrosion Resistance | Magnetism | Typical Use |
|---|---|---|---|---|
| SUS430 | Ferritic | Medium (good in nitric acid, atmospheric) | Magnetic | Kitchenware, decoration, burners |
| SUS304 | Austenitic | Excellent | Essentially non-magnetic | Tableware, medical, food equipment |
| SUS410 | Martensitic | Medium | Magnetic | Knives, bearings, shafts |
Typical Applications
SUS430 is specified where corrosion demands are moderate and cost matters: kitchen utensils and sink basins, decorative panels and outdoor advertising columns, burner and gas appliance parts, bolts, nuts and screens, anti-theft window mesh, automotive trim and exhaust components, and applications requiring stress-corrosion resistance in dry or mildly corrosive environments. Surfaces can be supplied as 2D, 2B, No.4 brushed, HL, BA or mirror finish.
Common Misconceptions
"SUS430 rusts easily." It resists atmospheric and nitric-acid attack well; problems appear mainly in chloride environments where an austenitic grade is the correct choice.
"430 is not food safe." For dry and mildly acidic food contact it is accepted; for prolonged acidic or salty contact, 304 or 316 is recommended.
"430 cannot be welded." Standard 430 is sensitive to grain growth and sensitization, but with low heat input, matching filler and the stabilized 430Ti/430LX variants, sound joints are achievable.
Frequently Asked Questions
Is SUS430 magnetic?
Yes. As a ferritic grade it is strongly magnetic, which is useful for electromagnetic devices and magnetic separators.
Why is SUS430 cheaper than SUS304?
It contains no nickel, and nickel is the most expensive alloying element in stainless steel. The price difference reflects that chemistry directly.
What is the difference between SUS430 and SUS430F?
SUS430F has a higher sulfur content (0.15–0.30%) for free machining. It machines faster but is difficult to weld.
Can SUS430 replace SUS304 in kitchenware?
Only where the environment is mild and dry. For acidic foods, salt exposure or repeated cleaning with chlorides, 304 remains the safer choice.
Does cold working affect SUS430?
Yes. Cold working raises hardness and strength, can slightly reduce corrosion resistance, and is used intentionally to make spring-like parts.
Which standard governs SUS430?
JIS G4303 (bars) and JIS G4305 (cold-rolled sheet and strip); equivalent ASTM material is A240/A276 for plate, sheet and bar.
