Steel 8620 · supply condition · default condition
Steel 8620-HR
Properties of the HR condition, compared with the other 8620 tempers.
Standard stocked condition for bar and plate that will be machined and then carburized or Q&T.
What is 8620-HR?
8620-HR is 8620 supplied in the HR condition — standard stocked condition for bar and plate that will be machined and then carburized or Q&T. 8620-HR 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). 8620-HR 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).
Advantages
- Easy to machine — 62/100, better than 89% of steel grades
- Ductile — tolerates forming and impact — 28%, better than 88% of steel grades
- Polishes to a fine finish — 70/100, better than 87% of steel grades
8620-HR properties
Typical room-temperature values for 8620-HR — 12 properties are specific to this condition; the rest are grade-level values shared by every 8620 temper. Each bar shows where the value sits among the steel grades in FabDigit's library — further right is higher.
Physical3
8620-HR 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-HR 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-HR 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-HR 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-HR takes about 30 MJ of energy and emits 2.1 kg of CO₂ — more than 55% of steel grades. Typical recycled content is 30%.
Manufacturability7
8620-HR'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.
Other 8620 tempers and conditions
8620 is also supplied in 9 other conditions. The full side-by-side table is on the 8620 overview.
- HRDefaultStandard stocked condition for bar and plate that will be machined and then carburized or Q&T.385 MPa yield · 183 HB
- Q&TChoose when the whole section must carry load (shafts, arbors) rather than only a carburized surface.850 MPa yield · 31 HRC
- CarburizedThe main reason to specify 8620: hard wear/pitting-resistant case on a tough core for gears, splines and pins.850 MPa yield · 60 HRC
- CDChoose for close-tolerance, good-finish bar with higher yield strength where no further heat treatment is planned.550 MPa yield · 205 HB
- HIPPick when residual porosity from printing/sintering must be closed for fatigue-critical gear or shaft parts.430 MPa yield · 200 HB
- AnnealedPick for maximum machinability, deep cold forming or before re-heat-treatment.385 MPa yield · 149 HB
- As PrintedUse for additively made gear-steel prototypes and small-lot parts that will subsequently be carburized or Q&T.380 MPa yield · 190 HB
- NormalizedUse to homogenize forgings/bar and get uniform grain size and good toughness before carburizing.360 MPa yield · 183 HB
Working with 8620-HR
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.
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.
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 | — |
8620-HR — frequently asked
What is 8620-HR used for?
8620-HR is typically used for gears, ring gears and camshafts. In short: best carburizing steel.
What is the yield strength of 8620-HR?
8620-HR 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-HR 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-HR 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-HR?
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-HR 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-HR?
8620-HR 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.
Can FabDigit make parts in 8620-HR?
Yes — 8620-HR 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. Nothing on this page is a certification — request mill certs, CoC or material test reports with your order.