SUS430 vs SUS430F: Composition

When choosing stainless steel for industrial applications, two common grades are SUS430 (also known as 430 stainless steel) and SUS430F. Both belong to the ferritic stainless steel family, but they have distinct properties and are designed for different purposes.

In this guide, we will compare SUS430 and SUS430F in terms of composition, key differences, and their respective applications. This comparison will help you understand which material is best suited for your specific needs.

 

What is SUS430 Stainless Steel?
SUS430, or 430 stainless steel, is a ferritic stainless steel grade with moderate corrosion resistance and excellent formability. It is primarily used for applications that require high strength and resistance to oxidation, but in mild environments. SUS430 contains around 16-18% chromium and less than 0.75% nickel, making it magnetic and suitable for parts that require magnetic properties.

 

What is SUS430F Stainless Steel?

SUS430F is a free-machining version of SUS430, with an added amount of sulfur (S), which improves its machinability. The higher sulfur content (up to 0.30%) makes SUS430F easier to machine, allowing for more complex shapes and smooth finishes. This makes SUS430F ideal for precision parts that need to be produced at a high volume.

 

SUS430 vs SUS430F: Composition

The main difference lies in the sulfur (S) content: SUS430F (F stands for free-machining) has significantly higher sulfur content (0.15-0.30%) and manganese (Mn) content (up to 1.25%) compared to SUS430 (maximum sulfur content of 0.03%, maximum manganese content of 1%). Sulfur is added to SUS430F, and sometimes molybdenum (Mo) is also added, to improve its machinability.

Grade N		C	Mn	Si	P	S	Cr	Mo	Ni	N
430	min. max.	- 0.12	- 1	- 1	- 0.04	- 0.030	16 18	-	- 0.50	-
430F	min. max.	- 0.12	- 1.25	- 1	- 0.06	0.15 -	16 18	-	-	-

 

AISI 430 Stainless Steel Equivalent

Grade	UNS No	Old British		Europe Euronorm		Swedish SS	Japan JIS
		BS	En	No	Name
430	S43000	430S17	60	1.4016	X8Cr17	2320	SUS 430
430F	S43020	-	-	1.4104	X12CrMoS17	2383	SUS 430F

 

SUS430 vs SUS430F: Mechanical Properties

Grade	Elastic Modulus (GPa)	Density (kg/m3)	Mean Coefficient of Thermal Expansion (μm/m/°C)			Thermal Conductivity (W/m.K)		Electrical Resistivity (nΩ.m)	Specific Heat 0-100°C (J/kg.K)
			0-100°C	0-315°C	0-538°C	at 100°C	at 500°C
430	200	7750	10.4	11.0	11.4	26.1	26.3	600	460
430F	200	7750	10.4	11.0	11.4	26.1	26.3	600	460

 

SUS430 vs SUS430F:  Machinability:

SUS430: While it is fairly easy to machine compared to austenitic steels, it still requires more attention to cutting tools and speed settings than SUS430F.

SUS430F: The addition of sulfur improves machinability significantly. SUS430F is designed for parts that require precision machining, such as screws, bolts, and small fasteners.

 

SUS430 vs SUS430F:  Corrosion Resistance:

SUS430: Offers good corrosion resistance in mild atmospheric conditions but is less resistant to chlorides (e.g., saltwater) compared to 304 stainless steel.

SUS430F: The higher sulfur content in SUS430F reduces its overall corrosion resistance compared to SUS430, especially in environments with chlorides.

 

SUS430 vs SUS430F: Applications:

SUS430: Best suited for decorative applications, appliances, and automotive parts where moderate corrosion resistance is acceptable, but magnetism is a benefit.

SUS430F: Preferred for applications requiring high machinability like precision fasteners, valves, and components for high-volume manufacturing.

 

Why Choose Gnee for SUS430 and SUS430F Stainless Steel?

Gnee has over 18 years of experience providing high-quality stainless steel products globally. Whether you're looking for SUS430 for decorative applications or SUS430F for precision machining, we offer custom sizes, finishes, and competitive prices.
Wide Range of Products: We provide SUS430 and SUS430F in various forms, including bars, plates, and custom cuts.
Global Shipping: We offer fast delivery and ship worldwide, ensuring that your materials arrive safely and on time.