SAE 8620 is a highly valued steel alloy known for its blend of strength, hardness, and wear resistance. This alloy, also identified as UNS G86200, is widely used in making components for automobiles, machinery, and defense equipment. Its versatility makes it a top choice in various industrial applications.
Sae 8620 chemical composition
| Element | Content (%) |
| Iron, Fe | 96.895-98.02 |
| Manganese, Mn | 0.700-0.900 |
| Nickel, Ni | 0.400-0.700 |
| Chromium, Cr | 0.400-0.600 |
| Carbon, C | 0.180-0.230 |
| Silicon, Si | 0.150-0.350 |
| Molybdenum, Mo | 0.150-0.250 |
| Sulfur, S | ≤ 0.0400 |
| Phosphorous, P | ≤ 0.0350 |
SAE 8620 Alloy Steel Physical Properties
| Properties | Metric | Imperial |
| Density | 7.85 g/cm3 | 0.284 lb/in³ |
The equivalent grade to EN8 in the BS 970-1991 standard is typically referred to as 080M40 steel.
AISI 8620 Mechanical Properties
| Properties | Metric | Imperial |
| Tensile strength | 530 MPa | 76900 psi |
| Yield strength | 385 MPa | 55800 psi |
| Elastic modulus | 190-210 GPa | 27557-30458 ksi |
| Bulk modulus (typical for steel) | 140 GPa | 20300 ksi |
| Shear modulus (typical for steel) | 80 GPa | 11600 ksi |
| Poisson’s ratio | 0.27-0.30 | 0.27-0.30 |
| Izod Impact | 115 J | 84.8 ft.lb |
| Hardness, Brinell | 149 | 149 |
| Hardness, Knoop (converted from Brinell hardness) | 169 | 169 |
| Hardness, Rockwell B (converted from Brinell hardness) | 80 | 80 |
| Hardness, Vickers (converted from Brinell hardness) | 155 | 155 |
| Machinability (hot rolled and cold drawn, based on 100 machinability for AISI 1212 steel) | 65 | 65 |
Thermal Properties of SAE 8620
| Properties | Metric | Imperial |
| Thermal conductivity | 46.6 W/mK | 323 BTU in/hr.ft².°F |
Sae 8620 Equivalent Material
| AISI 8620 | AMS 6274 | AMS 6276 | AMS 6277 | AMS 6375 | ASTM A29 |
| ASTM A322 | ASTM A331 | ASTM A506 | ASTM A507 | ASTM A513 | ASTM A519 |
| ASTM A646 | ASTM A752 | ASTM A829 | MIL S-8690 | SAE J1397 | SAE J404 |
| AFNOR 20 NCD 2 | AFNOR 22 NCD 2 | DIN 1.6523 | UNI 20 NiCrMo 2 | JIS SNCM 21 | JIS SNCM 21 H |
| B.S. 805 H 20 | B.S. 805 M 20 | AMS 6274G | AMS 6276C | AMS 6277A | ASTM A505 |
| MIL SPEC MIL-S-16974 | SAE J404 | SAE J770 |
Uses of AISI 8620 Steel
AISI 8620 steel is known for its versatility and is widely used in various fields. It is particularly valued in the automotive industry for making critical parts such as gears and shafts due to its strength and durability. This steel is also used in agricultural machinery and general engineering applications, where its excellent wear resistance comes into play. Common automotive components made from AISI 8620 include camshafts, drive shafts, transmission cases, differential housing assemblies, axle housings, flywheels, connecting rods, crankshafts, and steering knuckles. Its ability to withstand stress and resist wear makes it a reliable choice for these demanding applications.
SAE 8620 Corrosion Resistance
SAE 8620 steel offers notable corrosion resistance, thanks to its high chromium content. This makes it well-suited for environments exposed to corrosive elements such as seawater or acid rain. The elevated chromium level also enhances its oxidation resistance, allowing the steel to maintain its performance at high temperatures, up to around 650°F (343°C). These properties make SAE 8620 a reliable choice for applications in marine settings and other challenging environments where corrosion resistance is crucial.
AISI 8620 Heat Treatment
AISI 8620 steel is highly adaptable to heat treatment, which allows it to achieve specific mechanical properties based on the application requirements. In the quenching process, the steel is heated to a temperature above its critical point and then rapidly cooled in oil or water. This method enhances the steel’s hardness and strength. On the other hand, normalizing involves heating the steel to a temperature above its critical point and then allowing it to cool slowly in air, which improves its toughness and reduces internal stresses. Depending on the heat treatment method and subsequent tempering, SAE 8620 can achieve tensile strengths ranging from 545 MPa (79 ksi) to 795 MPa (115 ksi).
SAE 8620 Steel Machining
AISI 8620 steel is known for its excellent machinability, largely due to its low carbon content and the inclusion of alloying elements like molybdenum. These factors reduce cutting forces during machining, making it easier to work with. This property is especially beneficial for manufacturing precision components with tight tolerances and complex shapes, such as those used in firearms or aircraft. Additionally, its low sulfur content helps minimize tool wear, improving production efficiency and reducing costs per part. This combination of features ensures that AISI 8620 is a reliable choice for high-precision applications.
Conclusion
AISI 8620 stands out as a premier steel alloy, known for its exceptional combination of strength, hardness, and wear resistance. Its versatility makes it ideal for a wide range of applications, from automotive parts and agricultural machinery to defense equipment, firearms, aircraft components, and marine environments. The high chromium content provides excellent corrosion resistance, while the alloy’s machinability allows for efficient production with minimal tool wear. With proper heat treatment, AISI 8620 can achieve tensile strengths between 545 MPa (79 ksi) and 795 MPa (115 ksi), making it suitable for precision components with stringent tolerances. Overall, AISI 8620 is a top-performing steel alloy, offering reliable and high-quality performance across various industries.
FAQs
What is the SAE 8620 material standard?
SAE 8620 is a case-hardening steel that includes chromium, nickel, and molybdenum as its alloying elements. It is known for its good toughness, strength properties, and higher core strength compared to grades 8615 and 8617. This makes it suitable for applications requiring enhanced surface hardness while maintaining a tough core.
What grade is SAE 8620 equivalent to?
SAE 8620 steel is equivalent to EN 36 steel under the previous BS 970: 1955 standard. This equivalence indicates that SAE 8620 and EN 36 have similar chemical compositions and mechanical properties, making them suitable for comparable applications.
What is the difference between AISI 8620 and SAE 8620?
AISI 8620 and SAE 8620 are the same material, with AISI 8620 being a low alloy case-hardening steel containing nickel, chromium, and molybdenum, typically with a maximum hardness of HB 255. SAE 8620 offers high external strength and good internal toughness, enhancing wear resistance.
