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AISI 430 F

AISI 430 F is a tempered martensitic chromium steel that is resistant to rust and acid. The addition of sulfur improves machinability, but the corrosion resistance is reduced by the sulfur despite the high chromium content.

The main use of AISI 430 F stainless steel is in media that cause pitting or crevice corrosion. In addition, due to its excellent machinability, this stainless steel is used in the automotive industry, spindle and screws, hydraulics and as structural parts in water and steam.

In the manufacture of screws, axles, spindle and nuts and fittings, stainless steel alloy 430f steel magnetic is also used.

AISI 430FSpecial Steel

Overview of the most important steel

SS 2383, UNS S43020, AFNOR Z13CF17, BS 441S29, UNI X10CrS17, JIS SUS430F, GB Y10Cr17, 1.4104

Chemical composition

C Si Mn P S Cr Mo Ni Ti
min. 0,10 0,15 15,5 0,20
max. 0,17 1,0 1,50 0,04 0,35 17,5 0,60


Weldability bad
Machinability good 7 (1 = poor – 10 = good)
Polishing not possible
Corrosion resistance low
Corrosion class 2 (0 = weak – 5 = good)
Magnetisability available


Care is required during forging, as a ferritic-austenitic microstructure is formed due to the high sulfur content. During forging, the martensitic material is heated slowly to 850°C, with a progressive increase to 1,100°C – 1,130°C. The forging process takes place at 1,130°C and 750°C.


AISI 430f steel is usually not welded. The mechanical-technological values in the weld seam and the heat-affected zone can be very different from the base material without additional post-weld heat treatment.

Soft annealing

Soft annealing of the material takes place at 750°C to 850°C. This is followed by furnace or air cooling.

Corrosion resistance

The high content of sulfur affects the corrosion resistance of AISI 430F.

Cold forming

Cold forming is possible with SS 430F stainless steel.


The ferritic steel can be hardened at 950°C to 1070°C. The subsequent cooling should be carried out in the cooling water. Subsequent cooling should be carried out in the media of polymer, oil or air.

Heat treatment

Temperature in °C Cooling
Hot forming 1.100 – 800 air
Heat treatment
Soft annealing (+ A) 750 – 850 furnace, air
Tempering (+ QT)
Hardening 950°C – 1.070°C polymer, oil, air
Tempering (+ QT650) 550°C – 650°C air


Cold forming is possible
Spent processing is possible
Cold heading uncommon
Free-form and drop forging rare
Polishing not possible

Physical Properties

Density in kg/dm3 7,7
Electrical resistance at 20°C in (Ω mm2)/m 0,7
Thermal conductivity at 20°C in W/(m K) 25
Specific heat capacity at 20°C in J/(kg K) 460
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Popular steel:
17 4ph, aisi 430f

Important questions

What are the key properties of AISI 430F stainless steel?
AISI 430F stainless steel is known for its good corrosion resistance, excellent machinability, and moderate strength. It contains 16-18% chromium and 1% molybdenum, which enhance its corrosion resistance. The addition of sulfur improves its machinability.

How does AISI 430F compare to other stainless steels like 304 or 316?
AISI 430F has better machinability due to its sulfur content but lower corrosion resistance compared to 304 and 316. While 304 and 316 are austenitic and non-magnetic, 430F is martensitic and magnetic. 316 also contains molybdenum, which provides superior corrosion resistance in harsh environments.

What are the common applications of AISI 430F stainless steel?
AISI 430F is commonly used in the manufacturing of precision parts such as screws, bolts, and nuts. It is also used in the automotive industry, mechanical engineering, and the production of household appliances.

Is AISI 430F suitable for high-temperature applications?
AISI 430F is not generally recommended for high-temperature applications due to its lower heat resistance compared to other stainless steels like 304 and 316. It performs better in moderate temperature environments.

What are the machining characteristics of AISI 430F?
AISI 430F is highly machinable due to the addition of sulfur, which acts as a lubricant during machining. It allows for high-speed machining and is often used when precision and efficiency are required. However, the sulfur addition can slightly reduce its corrosion resistance compared to other grades.