ASTM 440A Stainless Steel

1.Core Chemical Composition (wt%)

Element	Content Range
Carbon (C)	0.60–0.75
Chromium (Cr)	16.00–18.00
Manganese (Mn)	≤1.00
Silicon (Si)	≤1.00
Molybdenum (Mo)	≤0.75
Nickel (Ni)	≤0.60
Phosphorus (P)	≤0.040
Sulfur (S)	≤0.030
Iron (Fe)	Balance

2. Key Performance Characteristics

Hardness Level: After quenching and tempering, its hardness can reach 52–55 HRC. This is lower than 440B and 440C, but higher than most common stainless steels.

Toughness Advantage: It has the best toughness in the 440 series. It is less prone to brittle fracture under impact compared with 440B and 440C.

Corrosion Resistance: Its moderate carbon content reduces the precipitation of chromium carbides. This gives it better resistance to atmospheric corrosion and fresh water than 440B and 440C. It is still not suitable for seawater or strong acid/alkali environments.

Processability: It can be easily machined in the annealed state. Welding is not recommended unless preheating and post-weld heat treatment are strictly performed to avoid hardness increase and cracking.

3. Typical Application Fields

Cutting Tools: Low-load knives, scissors, and razor blades that require a balance of sharpness and toughness.

Mechanical Components: Bearings, valve parts, and shafts used in non-corrosive environments.

Consumer Products: Watch cases, knife handles, and hardware accessories that need wear resistance and a polished finish.