Steel 8620
AISI/SAE 8620 · UNS G86200 · EN 1.6523, 21NiCrMo2 · JIS SNCM220 · GB 20CrNiMo
8620 is a low-carbon Ni-Cr-Mo case-hardening (carburizing) steel, essentially equivalent to GB 20CrNiMo / DIN 21NiCrMo2 / 1.6523.
Values for the HR condition
8620 tempers and conditions
8620 is supplied in 10 conditions, soft to hard. HR is the default FabDigit quotes; the values on this page are for it.
Compare all 10 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
austenitized ~900 °C, air cooled | Use to homogenize forgings/bar and get uniform grain size and good toughness before carburizing. | 360 | 630 | 26 | 10 HRC | 8 % IACS |
binder-jetted / L-PBF and sintered 8620 powder | Use for additively made gear-steel prototypes and small-lot parts that will subsequently be carburized or Q&T. | 380 | 640 | 6 | 11 HRC | 7 % IACS |
HRDefault Hot rolled | Standard stocked condition for bar and plate that will be machined and then carburized or Q&T. | 385 | 635 | 28 | 183 HB | — |
full/subcritical anneal, softest machining condition | Pick for maximum machinability, deep cold forming or before re-heat-treatment. | 385 | 540 | 31 | 149 HB | — |
Hot isostatic pressed | Pick when residual porosity from printing/sintering must be closed for fatigue-critical gear or shaft parts. | 430 | 720 | 18 | 14 HRC | 8 % IACS |
cold finished + 550–650 °C stress relief | Pick for cold-finished bar that must stay straight and dimensionally stable through heavy machining. | 500 | 660 | 18 | 12 HRC | 8 % IACS |
Cold drawn | Choose for close-tolerance, good-finish bar with higher yield strength where no further heat treatment is planned. | 550 | 690 | 15 | 205 HB | — |
Cold rolled | Sheet and strip form for stamped, then carburized parts; better surface and thickness tolerance than hot rolled. | 560 | 700 | 13 | 15 HRC | 8 % IACS |
Quenched and tempered | Choose when the whole section must carry load (shafts, arbors) rather than only a carburized surface. | 850 | 1,050 | 15 | 31 HRC | — |
gas carburized, quenched, low tempered (case 58–63 HRC) | The main reason to specify 8620: hard wear/pitting-resistant case on a tough core for gears, splines and pins. | 850 | 1,100 | 10 | 60 HRC | — |
What is 8620?
8620 is a low-carbon Ni-Cr-Mo case-hardening (carburizing) steel, essentially equivalent to GB 20CrNiMo / DIN 21NiCrMo2 / 1.6523. It is chosen for gears, pinions, shafts, splines and bushings where a hard, wear-resistant carburized case (58–63 HRC) is wanted over a tough, moderately strong core, and it machines and welds far better than higher-carbon through-hardening alloys. Limits: it has essentially no corrosion resistance (must be oiled, plated or nitrided/black-oxided), core strength is modest unless direct-quenched, and thick sections have limited hardenability compared with 4340 or 8822. 8620 has a density of 7.85 g/cm³ (0.284 lb/in³), heavier than 56% of steel grades. It melts at 1,425°C (2,597 °F). 8620 has a yield strength of 385 MPa (55.8 ksi) and a tensile strength of 635 MPa (92.1 ksi) — weaker than 65% of steel grades. Elongation at break is 28% and the elastic modulus is 205 GPa (29.7 Msi).
What is 8620 used for?
- Gears
- Ring gears
- Camshafts
Advantages
- Ductile — tolerates forming and impact — 28%, better than 89% of steel grades
- Easy to machine — 62/100, better than 89% of steel grades
- Polishes to a fine finish — 70/100, better than 87% of steel grades
8620 properties
Typical room-temperature values for 8620-HR; bars are the position among steel grades.
Physical3
8620 has a density of 7.85 g/cm³ (0.284 lb/in³), heavier than 56% of steel grades. It melts at 1,425°C (2,597 °F).
Mechanical14
8620 has a yield strength of 385 MPa (55.8 ksi) and a tensile strength of 635 MPa (92.1 ksi) — weaker than 65% of steel grades. Elongation at break is 28% and the elastic modulus is 205 GPa (29.7 Msi).
Thermal6
8620 is rated for continuous service to 400°C (752 °F). It conducts heat at 46.6 W/m·K (26.9 BTU/hr·ft·°F), better than 74% of steel grades. Thermal expansion is 11.6 µm/m·K (6.44 µin/in·°F).
Electrical3
8620 conducts electricity at 8 % IACS, better than 55% of steel grades.
Chemical & Environmental3
Corrosion resistance is not recommended (11/100), worse than 73% of steel grades.
Sustainability4
Producing a kilogram of 8620 takes about 30 MJ of energy and emits 2.1 kg of CO₂ — more than 56% of steel grades. Typical recycled content is 30%.
Manufacturability7
8620's machinability is good (62/100, better than 89% of steel grades); weldability good (60/100); formability good (55/100).
Common Calculations5
Values are nominal handbook figures for design screening. Certified mill or lot data ships with every FabDigit order on request.
Strength versus weight in the steel family
Yield strength against density for every steel grade FabDigit runs. 8620 is highlighted; hover a dot for its name, or open the interactive family chart.
Working with 8620
Is 8620 easy to machine?
Machines well at ~65 % of AISI 1212 in HR/annealed condition; finish-machine before carburizing and allow grinding stock for case distortion.
Can 8620 be welded?
Weldable with low-hydrogen consumables at 0.20 % C; preheat 150–250 °C, use matching low-alloy filler and post-weld stress relieve; never weld a carburized surface.
Can 8620 be formed, bent or molded?
Cold heading and moderate bending are fine in annealed/HR condition; hot forge 1150–1230 °C and normalize afterwards to restore grain size.
Manufacturability
The process limits FabDigit's quote engine applies to 8620. Design inside these and the part quotes instantly; outside them it routes to an engineer.
CNC machining
| Machinability | Better62 / 100 |
|---|---|
| ISO material group | P.2 |
| Cutting speed (rough / finish) | 170 / 200 m/min |
| Minimum wall | 0.8 mm |
| Minimum internal radius | 1 mm |
| Drill depth limit | 4.5× diameter |
| Best surface (machined / polished) | Ra 1.6 / 0.8 µm |
| Hardenable after machining | Yes |
Sheet metal
| Formability | Good55 / 100 |
|---|---|
| Weldability | Better60 / 100 |
8620 chemical composition (wt %)
Limits by weight percent from the governing specification, written the way the spec states them — a single maximum for impurities, a range for alloying elements, and the base element as balance. Nominal is the typical mid-range value.
| Element | Spec limit (wt %) | Nominal |
|---|---|---|
| Cheat analysis, SAE/ASTM A29 | 0.18 – 0.23 | 0.2 |
| Mn | 0.7 – 0.9 | 0.8 |
| Si | 0.15 – 0.35 | 0.25 |
| Ni | 0.4 – 0.7 | 0.55 |
| Cr | 0.4 – 0.6 | 0.5 |
| Mo | 0.15 – 0.25 | 0.2 |
| P | ≤ 0.04 | |
| Smax; 8620H/resulfurized variants differ | ≤ 0.04 | |
| Fe | balance |
What surface finishes work on 8620?
No anodizing (ferrous); protect with black oxide, phosphate, zinc or zinc-nickel plating, or oil — post-carburizing grinding gives the final gear-tooth finish.
Surface treatments FabDigit runs on steel parts — pick them in the quote configurator or call them out on the drawing. Each links to its datasheet in the surface-finish library (thickness, specs, call-out, material verdicts).
Plating
CVD Coating
Black / Phosphate
Thermal Spray
Equivalent designations
Standards and trade names that resolve to Steel 8620 in FabDigit's catalog. Equivalence is nominal — check the exact specification when certification matters.
How much does 8620 cost?
8620 is a standard-cost steel ($$), cheaper than about 62% of the materials FabDigit quotes. Part price depends far more on geometry, tolerance and quantity than on the raw stock — upload a CAD file for a live quote.
8620 — frequently asked
What is 8620 used for?
8620 is typically used for gears, ring gears and camshafts. In short: best carburizing steel.
What is the yield strength of 8620?
8620 has a typical yield strength of 385 MPa (55.8 ksi) and a tensile strength of 635 MPa (92.1 ksi) — weaker than 65% of steel grades. Strength varies by condition: see the 10 listed tempers.
Is 8620 easy to machine?
Reasonably — machinability is rated good (62/100, better than 89% of steel grades). Machines well at ~65 % of AISI 1212 in HR/annealed condition; finish-machine before carburizing and allow grinding stock for case distortion.
Can 8620 be welded?
Yes — weldability is rated good (60/100). Weldable with low-hydrogen consumables at 0.20 % C; preheat 150–250 °C, use matching low-alloy filler and post-weld stress relieve; never weld a carburized surface.
What surface finishes work on 8620?
No anodizing (ferrous); protect with black oxide, phosphate, zinc or zinc-nickel plating, or oil — post-carburizing grinding gives the final gear-tooth finish.
Can 8620 be formed, bent or molded?
Cold heading and moderate bending are fine in annealed/HR condition; hot forge 1150–1230 °C and normalize afterwards to restore grain size.
What is the maximum service temperature of 8620?
8620 is rated for continuous use to about 400°C (752 °F). Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
What is the difference between 8620-HR and 8620-CR?
HR is the default condition — standard stocked condition for bar and plate that will be machined and then carburized or Q&T. CR: sheet and strip form for stamped, then carburized parts; better surface and thickness tolerance than hot rolled. Yield strength is 385 MPa in HR versus 560 MPa in CR.
How much does 8620 cost?
8620 is a standard-cost steel ($$), cheaper than about 62% of the materials FabDigit quotes. Part price depends far more on geometry, tolerance and quantity than on the raw stock — upload a CAD file for a live quote.
Can FabDigit make parts in 8620?
Yes — 8620 is available for CNC machining and sheet metal with instant online pricing. Upload a STEP file to get a price and a DFM check.
Sources
- ASTM A29/A29M — Steel Bars, Carbon and Alloy, Hot-Wrought — ASTM International (2020)
- SAE J404 — Chemical Compositions of SAE Alloy Steels — SAE International (2021)
- GB/T 3077 (20CrNiMo) — SAC (2015)
- EN 10084 — Case hardening steels (1.6523 / 21NiCrMo2-2) — CEN (2008)
- ASM Handbook Vol.1 — Properties and Selection: Irons, Steels — ASM International (1990)
- ASM Handbook Vol.4 — Heat Treating (carburizing) — ASM International (1991)
- MatWeb / MMPDS typical property listings for AISI 8620 — MatWeb / Battelle (2023)
- Binder-jet and L-PBF low-alloy 8620 powder data sheets — ExOne / Desktop Metal (2022)
- 20CrNiMo — Mysteel / 1688 (2026)
Property data is compiled from published supplier and standards handbooks and normalised for comparison; hardness values on non-Brinell scales are converted approximately for charting only. Manufacturability limits are FabDigit quote-engine defaults and may be relaxed by engineering review. Nothing on this page is a certification — request mill certs, CoC or material test reports with your order.