AISI 440C (UNS S44004, ASTM A276-98b, JIS SUS440C)stainless steel is a high carbon and high chromium martensitic stainless steel with a carbon content of 1.0% and a chromium content of 17%.
AISI 440C stainless steel is mainly used to manufacture bearing parts that work in corrosive environments and nonlubricated strong oxidizing atmospheres.
AISI 440C has good high-temperature dimensional stability, so it can also be used as a corrosion-resistant high-temperature bearing steel. In addition, it can also be used to manufacture high-quality knives, such as medical surgical knives, scissors, nozzles, bearings, etc.
The ability of 440C to withstand dynamic loads is relatively low.
AISI 440C has good welding performance, making it more adaptable in the connection process of structural components such as pipelines and pressure vessels.
AISI 440C has good stress relaxation resistance and can maintain stable mechanical properties and dimensional stability under long-term stress.
Mechanical properties of 440C: tensile strength of 800 MPa, yield strength of 550 MPa, and elongation of 25%.
AISI 440C has good friction resistance in high-temperature environments and is suitable for manufacturing components under high-temperature friction conditions.
Standard Specifications
ASTM A276, A314, A484, A473, A493, A580
AMS 5618, 5630, 5880
MIL SPEC MIL-S-862
FEDERAL QQ-S-763
ASME SA276
UNS S44004
SAE J405 (51440C)
SAE 51440C
DIN 1.4125
Equivalent grades
| SAE | ASTM | JIS | NF | DIN | UNS | GB | AISI | IOS | GOST | EN |
|---|---|---|---|---|---|---|---|---|---|---|
| 51440C | A276-98b | SUS440C | Z100CD17 | X105CrMo17(1.4125 ) | S44004 | 11Cr17 | 440C | A-16 | 95Ch18 | 1.4125 |
Chemical composition
| Grade | C | Si | Ni | S | Mn | P | Cr | Fe | |
| 440C | min. | 0.95 | - | - | - | - | - | 16.00 | - |
| max. | 1.20 | 1.00 | - | 0.030 | 1.00 | 0.040 | 18.00 | - | |
Mechanical Properties
| Grade | Tensile Strength (MPa) min | Elongation (% in 50mm) min | Yield Strength 0.2% Proof (MPa) min | Hardness | |
| Rockwell B (HR B) max | Brinell (HB) max | ||||
| 440C | 758 | 14 | 448 | 269 | - |
Application
Injection molds, cutting tools, surgical tools, custom knives, food processing equipment, bearings, petroleum pumps and valves.
Heat Treatment
Warmup: 1400/1500F (760/815C) is the conventional warmup stage; for imbalanced geometries or complex designs, the optional preheat step is 1100/1250F (590/675C), equalized.
Austenitizing: Equilibration at 1850/1900F (1010/1020C) for 30 to 45 minutes at room temperature.
Quenching: Air, positive vacuum, at least 2 bar, to 125F (50C). Stop the supply of oil below 1000F (540C). Air cooled to 65°C/150°F. Temper right away.
Temperature: air-cooled for two hours at 400/800F (205/425C). Exercise twice. Tempering should be avoided between 800 and 1100°F since it lowers corrosion resistance and hardness.
Cryogenic therapy: By changing retained austenite, freezing treatment can enhance long-term dimensional stability. Tempering must occur after the freezing procedure, which is often performed after the initial tempering.
Welding
Use stainless steel filler material made of 420 or 440C. Annealed Substance: While welding, keep the temperature above 600F (320C) and preheat to 600/800F (320/430C). After welding, reanneal or temper at 1200/1400F (650/760C) for four hours.
Preheat the hardened material to a minimum of 400F (205C), or 50F (30C) below the original tempering temperature. When welding, keep the temperature above 400F (205C). After welding, cool to 150F, or 65C. Temper right away at a temperature that is 25F (15C) lower than the original. 400F minimum (205C)
