440A stainless steel equivalent material

What material is AISI 440A?

AISI 440A is a high-carbon, high-chromium martensitic stainless steel with excellent hardness, wear resistance, and moderate corrosion resistance, making it an ideal material for cutting tools, blades, and surgical instruments. After heat treatment, it can achieve extremely high hardness, but due to its slightly lower carbon content, its machinability is superior to that of 440B/C.

 

What is 440A stainless steel equivalent to?

440A stainless steel equivalents include SAE 51440A, UNS S44002, ASTM A276, AMS 5631/5632, and China's 7Cr17, with close comparisons to Japanese AUS-6, all being hardenable martensitic steels known for good wear resistance and corrosion resistance, differing mainly in carbon content compared to 440B/C.

 

440A stainless steel  Chemical Composition %

Grade	C	Mn	P	S	Si	Cr	Mo	Fe
440A	0.60 - 0.75	1.0 max	0.4 max	0.3 max	1.0 max	16.0 - 18.0	0.75 max	Remainder

440A stainless steel  Mechanical Properties

Tensile Strength (ksi)	0.2% Yield Strength (ksi)	Elongation% in 2 inches
110	65	14

440A stainless steel  Physical Properties

	Units	Temperature in °C
Density	7.6 g/cm³	Room
Specific Heat	0.11 Kcal/kg.C	22°
Melting Point	1482 °C	-
Modulus of Elasticity	200 KN/mm²	20°
Electrical Resistivity	360 µΩ.cm	Room
Coefficient of Expansion	10.1 µm/m °C	20 - 100°
Thermal Conductivity	24.2 W/m -°K	20°

440A stainless steel  ASTM Specifications

Grade	Pipe / Tube (SMLS)	Bar	Forging	Wire
440A	A 511	A 276, A 314	A 473	A 580

 

What is the hardness of 440A Rockwell?
440A stainless attains a hardness of Rockwell C 56 and maximum toughness when heat treated. 440A stainless has been used for pivot pins, dental and surgical instruments, cutlery, valve parts, etc. This steel makes fair permanent magnets.

 

What is the difference between 440A and 440B?

The main difference between 440A and 440B stainless steel is their carbon content, which affects hardness and toughness: 440A has less carbon (around 0.60-0.75%), making it tougher and more corrosion-resistant but less hard, while 440B has more carbon (around 0.75-0.95%), giving it higher hardness and wear resistance than 440A, but slightly less corrosion resistance and toughness.

 

What are the differences between 440A and 440C stainless steel?
Both 440A and 440C are stainless steels, but their main difference lies in their carbon content. 440C has a significantly higher carbon content than 440A (440C has 0.95-1.2% carbon, while 440A has 0.6-0.75%), making 440C harder, more wear-resistant, and with better edge retention. 440A, on the other hand, prioritizes corrosion resistance and ductility, making it easier to sharpen, but it is softer and not suitable for heavy-duty use. To put it simply: 440A is suitable for economical kitchen knives, while 440C is suitable for high-end, more durable blades.