440A vs. 440B vs. 440C Stainless Steel: Key Differences?
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What is 440A Stainless Steel?
440A steel is a high-carbon martensitic stainless steel that combines good strength, moderate corrosion resistance, and excellent hardness and wear resistance. It contains approximately 0.60-0.75% carbon and 16.0-18.0% chromium, allowing it to achieve very high hardness through heat treatment. This makes it suitable for applications such as blades, surgical instruments, and ball bearings.
What is 440B Stainless Steel material?
440B stainless steel is a high-carbon martensitic chromium stainless steel with high hardness and high wear resistance, properties achieved through heat treatment. It is a versatile material suitable for demanding applications such as cutting tools, surgical instruments, and ball bearings. Its moderate corrosion resistance can be optimized through proper cleaning and passivation treatments, especially after machining.
What is 440C Stainless Steel?
440C is a high-carbon martensitic stainless steel known for its high hardness, strength, and wear resistance. It has a high chromium content (16-18%) and a carbon content of 0.95% to 1.20%, which allows it to achieve very high hardness through heat treatment. It is suitable for high-end tableware, bearings, and surgical instruments, among other applications.
Equivalent grades of 440 SS
|
American |
ASTM |
440A |
440B |
440C |
440F |
|
UNS |
S44002 |
S44003 |
S44004 |
S44020 |
|
|
Japanese |
JIS |
SUS 440A |
SUS 440B |
SUS 440C |
SUS 440F |
|
German |
DIN |
1.4109 |
1.4122 |
1.4125 |
/ |
|
China |
GB |
7Cr17 |
8Cr17 |
11Cr17 9Cr18Mo |
Y11Cr17 |
440A vs. 440B vs. 440C Stainless Steel: Chemical composition
|
Grades |
C |
Si |
Mn |
P |
S |
Cr |
Mo |
Cu |
Ni |
|
440A |
0.6-0.75 |
≤1.00 |
≤1.00 |
≤0.04 |
≤0.03 |
16.0-18.0 |
≤0.75 |
(≤0.5) |
(≤0.5) |
|
440B |
0.75-0.95 |
≤1.00 |
≤1.00 |
≤0.04 |
≤0.03 |
16.0-18.0 |
≤0.75 |
(≤0.5) |
(≤0.5) |
|
440C |
0.95-1.2 |
≤1.00 |
≤1.00 |
≤0.04 |
≤0.03 |
16.0-18.0 |
≤0.75 |
(≤0.5) |
(≤0.5) |
|
440F |
0.95-1.2 |
≤1.00 |
≤1.25 |
≤0.06 |
≥0.15 |
16.0-18.0 |
/ |
(≤0.6) |
(≤0.5) |
440A vs. 440B vs. 440C Stainless Steel:Physical properties
| Property | 440A | 440B | 440C |
|---|---|---|---|
| Tensile Strength (MPa) | 700–800 | 750–850 | 800–900 |
| Yield Strength 0.2% (MPa) | 450–500 | 450–500 | 500–550 |
| Hardness (HRC) | 44–48 | 48–52 | 54–58 |
| Elongation (%) | 12–15 | 10–12 | 8–10 |
440A vs. 440B vs. 440C Stainless Steel: Hardness
The hardness of 440A, 440B, and 440C stainless steel increases from A to C, with 440C being the hardest.
| Grades | Hardness, Annealing(HB) | Heat treatment(HRC) |
| 440A | ≤255 | ≥54 |
| 440B | ≤255 | ≥56 |
| 440C | ≤269 | ≥58 |
| 440F | ≤269 | ≥58 |
ASTM Specifications
| Grade | Pipe / Tube (SMLS) | Bar | Forging | Wire |
| 440A | A 511 | A 276, A 314 | A 473 | A 580 |
| 440B | - | A 276, A 314 | A 473 | A 580 |
| 440C | - | A 276, A 314 | A 473 | A 493 |
440A Vs. 440B Vs. 440C Stainless Steel: Corrosion Resistance
440A has the highest corrosion resistance among the three grades, followed by 440B, with 440C having the lowest. This is because the grades have increasing carbon content, and higher carbon levels decrease corrosion resistance while increasing hardness and wear resistance. Therefore, 440A is chosen when corrosion resistance is the priority, while 440C is used for applications needing the greatest hardness and strength.
440A Vs. 440B Vs. 440C Stainless Steel: Machinability
440C is the least machinable due to its high carbon content, while 440A is the most machinable because it has the lowest carbon content. 440B falls in the middle, offering a compromise between 440A's machinability and 440C's hardness. All three can be difficult to machine once heat-treated to high hardness, so it is recommended to machine them in the annealed (softened) condition, using tools like chip breakers and ceramic or carbide tooling.
440A vs. 440B vs. 440C Stainless Steel: Magnetic
All three stainless steels, 440A, 440B, and 440C, are magnetic because they are all martensitic stainless steels that can be hardened by heat treatment. The key difference between them is their carbon content, which increases from 440A to 440C, affecting hardness and corrosion resistance, but all remain magnetic in both annealed and hardened states.
If you have project needs for 440A, 440B, and 440C stainless steel bars, please feel free to place an order. GNEE has a large inventory of popular products for your selection. They can be processed into various practical product forms, including plates, coils, tubes, bars, and wires. For detailed chemical compositions and free samples, please contact our factory immediately. We offer competitive prices and excellent service.Email: info@gneestainless.com
