8620 SNCM220 1.6523 20NiCrMo2-2 Cold Rollled Seamless Steel Tube
Item specifics
- Outer diameter
- 83-254 mm
- Wall thickness
- 7 to 60 mm
- length
- 12 meters
- Cold drawn tolerance for OD and ID
- within ±0.2mm
- Cold rolled tolerance for OD and ID
- within ±0.1mm
Review
Description
Application
AISI 8620 Steel is a low alloy nickel, chromium, molybdenum case hardening steel, generally supplied in the as rolled condition with a maximum hardness HB 255max. SAE steel 8620 offers high external strength and good internal strength, making it highly wear resistant. AISI 8620 steel has a higher core strength than grades 8615 and 8617.
Annealing
AISI 8620 steel may be given a full anneal by heat to 820℃ – 850℃, and hold until temperature is uniform throughout the section and cool in furnace or air cooled.
Standard
Specifications
Dimensions：Outer diameter: 83-254 mm, Wall thickness: 7 to 60 mm, length: not more than 12 meters.
Tolerance for OD and ID：
Cold drawn: within ±0.2mm
Cold rolled: within ±0.1mm
Tolerance for Wall Thickness：
Hot rolled: within +/-5%,
Cold drawn: within 0.6mm
Process：Hot Rolled, Cold Drawn, Precision Rolled
Delivery Condition：Hot rolled, Cold drawn, Annealed, Normalized, Quenched and tempered.
Surface Condition：Black surface, Rough turned, Peeled.
Chemical requirements:
Grade | C | Mn | Pmax. | Smax. | Si | Cr | Mo | Ni |
8620 | 0.18-0.23 | 0.70-0.90 | 0.04 | 0.04 | 0.15-0.35 | 0.40-0.70 | 0.40-0.60 | 0.15-0.25 |
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 |
AISI 8620 Steel Grade Heat Treatment
Tempering
Tempering of heat treated and water quenched parts of 8620 steels (not carburized) is done at 400 F to 1300 F to improve case toughness with minimal effect on its hardness. This will also reduce the possibility of grinding cracks.
Hardening
The AISI steel 8620 will be austenitized at around 840°C – 870°C, and oil or water quenched depending upon section size and intricacy. Cool in Air or Oil required.
Normalizing
1675ºF (910ºC) and air cool. This is another method of improving machinability in 8620 material; normalizing might also be used prior to case hardening.
This alloy is used in the oil and gas industry as forged down-hole drilling tools such as drill collars. Other applications are forged gears, shafts for hydraulic presses, rolls for paper mills, pump shafts and tool holders
