Stainless steel plays a critical role in various industries, and AISI 430 stands out as a key grade in this family. AISI 430 belongs to the ferritic group of steels, known for its non-hardenable properties and straight chromium composition. This unique blend provides excellent corrosion resistance and good formability, making it suitable for numerous industrial applications.
One of the standout features of AISI 430 is its resistance to nitric acid, which makes it a preferred choice in certain chemical environments where durability against corrosive substances is essential.
For applications requiring precision machining, the 430F variant is widely used. Typically available in bar form, 430F is specially designed for automatic screw machines, ensuring smooth and efficient machining processes.
Another noteworthy variant is grade 434, which shares similarities with AISI 430 but includes molybdenum in its composition. This addition enhances its corrosion resistance, making grade 434 ideal for use in harsher environments where protection against corrosive elements is crucial.
These variations highlight the versatility and practicality of AISI 430 stainless steel in addressing diverse industrial needs.
AISI 430 Specification Comparison
| Grade | UNS No | Old British | Euronorm | Swedish SS | Japanese JIS | ||
| BS | En | No | Name | ||||
| 430 | S43000 | 430S17 | 60 | 1.4016 | X8Cr17 | 2320 | SUS 430 |
| 430F | S43020 | – | – | 1.4104 | X12CrMoS17 | 2383 | SUS 430F |
SS 430 Chemical Composition
| Carbon | Silicon | Manganese | Phosphorus | Sulphur | Nickel | Chromium | ||
| 430 | Specification (max) | 0.12 | 1.00 | 1.00 | 0.040 | 0.030 | 0.75 | 16.00 – 18.00 |
| (typical) | 0.048 | 0.36 | 0.42 | 0.024 | 0.010 | 0.17 | 16.28 |
SS430 Material Properties
|
0.2% Proof Stress
|
Tensile Strength
|
Elongation
|
Hardness
|
||
|
MPa
|
MPa
|
%
|
HB (max)
|
||
| 430 |
Specification (min)
|
205 | 450 | 20% (<= 1.2mm) | <= 183 |
| 22% (> 1.2mm) | |||||
|
typical values
|
325 | 515 | 28 | 145 |
AISI 430 Physical Properties
|
Property
|
At
|
Value
|
unit
|
|
Density
|
7,800
|
kg/m³
|
|
|
Melting Range
|
1425 – 1510
|
°C
|
|
|
Modulus of Elasticity
|
20°C
|
200
|
GPa
|
|
Shear Modulus
|
20°C
|
85
|
GPa
|
|
Poisson’s Ratio
|
20°C
|
0.30
|
|
|
Tdermal Conductivity
|
100°C
|
26.1
|
W / m. °C
|
|
Electrical Resistivity
|
25°C
|
0.60
|
micro-ohm . m
|
|
Electrical Conductivity
|
25°C
|
1.02
|
% IACS
|
|
Specific Heat
|
600 | J/kg. °C | |
|
Relative Magnetic Permeability
|
600 – 1100 | ||
|
Coefficient of Expansion
|
0 – 100°C | 10.4 | /°C |
| 0 – 315°C | 11.0 | /°C | |
| 0 – 540°C | 11.4 | /°C |
Toughness
Grade 430 stainless steel displays ductile fracture behavior at room temperature but loses toughness when welded. This limitation makes it unsuitable for structural applications
Pressure Vessels
According to AS1210 standards for pressure vessels, grade 430 can be used at temperatures up to 650°C in forms such as plates, seamless pipes, tubes, and bars
475°C Embrittlement
Ferritic stainless steels, including grade 430, become brittle when exposed to temperatures above 340°C, with the peak embrittlement occurring at 475°C. Heating the material above 515°C and then cooling rapidly can restore its toughness.
Sigma Phase Formation
Prolonged exposure to temperatures between 450°C and 810°C can lead to the formation of sigma phase, which reduces toughness and corrosion resistance.
Sensitization
Grade 430 may experience sensitization and a subsequent loss of corrosion resistance when heated above 880°C due to carbide precipitation. Annealing at 800°C can reverse sensitization. A stabilized version, 430Ti, includes titanium to mitigate this effect.
High-Temperature Corrosion
In air, grade 430 can withstand temperatures up to 870°C during intermittent use and 815°C for continuous service.
Cold Fabrication
Grade 430 is easy to work with standard sheet metal techniques, except oxygen cutting, which should be replaced with plasma cutting. Its deep drawability is comparable to carbon steel.
Forging
Grade 430 can be forged at temperatures between 850°C and 1120°C, with finishing down to 705°C. Annealing is recommended after forging to enhance properties.
Machinability
While easier to machine than austenitic grade 304, grade 430 requires more power and precision compared to carbon steel. The machinability of grade 430 is about 60% of that of resulfurized free-cutting carbon steel.
Heat Treatment
Solution annealing is performed at 1065–1120°C, followed by rapid cooling to prevent chromium carbide precipitation. Grade 430 cannot be hardened through heat treatment
Weldability
Grade 430 is challenging to weld using fusion techniques due to coarse ferrite grains, martensite at grain boundaries, and carbide precipitation, resulting in brittle and less corrosion-resistant welds. However, post-weld heat treatment can improve weld quality.
Spot, seam, and induction welding are suitable methods, with 430Ti offering better toughness and corrosion resistance in welded areas. Grade 309 filler metal is commonly used for welding grade 430.
Corrosion Resistance
Although grade 430 offers good corrosion resistance, its lower chromium content compared to austenitic grade 304 results in slightly reduced performance in corrosive environments.
Applications of Stainless Steel Grade 430
Stainless steel grade 430 is widely used in various industries due to its versatility and durability. Key applications include:
- Household Appliances: Commonly used in white goods like dishwashers, washing machines, and dryers for its corrosion resistance and ease of maintenance.
- Furniture and Storage: Ideal for benches and cabinets, offering a sleek appearance and robust performance.
- Automotive Industry: Frequently used for trim and decorative components in vehicles.
- Interior Design: Popular in architectural elements such as panels, fittings, and decorative fixtures for its aesthetic appeal and practicality.
Conclusion
Stainless steel grade 430 stands out as a dependable and versatile material, offering an excellent combination of properties suited for a wide range of applications. Its corrosion resistance, ease of machining, and fabrication flexibility make it a preferred choice for industries. From dishwasher linings and refrigerator panels to stove trim rings and automotive components, SS 430 proves its value in both functionality and durability. Its adaptability across various processes and industries highlights its importance as a practical and cost-effective solution.
FAQs
What is AISI 430 stainless steel?
AISI 430 is a ferritic stainless steel offering corrosion resistance similar to 304, suitable for forming applications like stretch forming, bending, and drawing without rapid hardening.
What is AISI 430 material?
AISI 430 is a ferritic stainless steel with chromium content, offering moderate corrosion resistance, good mechanical properties, and non-hardenable characteristics, suitable for general-purpose applications.
What is the composition of 430 stainless steel?
430 stainless steel has a composition of 16–18% chromium, ≤0.12% carbon, and 0–0.75% nickel, with minimal or no molybdenum, making it cost-effective.
