Steel 4620 · heat-treated state
Steel 4620 Carburized
Properties of the Carburized condition, compared with the other 4620 tempers.
Carburize at 900–930 °C, quench and low-temper for the intended service state: a 58–62 HRC wear-resistant case over a tough core for gears and pins, with machining and welding then ruled out.
What is 4620 Carburized?
4620 Carburized is 4620 heat treated to Carburized — carburize at 900–930 °C, quench and low-temper for the intended service state: a 58–62 HRC wear-resistant case over a tough core for gears and pins, with machining and welding then ruled out. 4620 Carburized has a yield strength of 650 MPa (94.3 ksi) and a tensile strength of 850 MPa (123 ksi) — stronger than 79% of steel grades. Elongation at break is 14% and the elastic modulus is 205 GPa (29.7 Msi). 4620 Carburized has a density of 7.85 g/cm³ (0.284 lb/in³), heavier than 56% of steel grades. It melts at 1,420°C (2,588 °F). HR is the default condition FabDigit quotes; Carburized is available on request or by drawing note.
Advantages
- High strength — 650 MPa (94.3 ksi), better than 79% of steel grades
Limitations
- Limited service temperature — 180°C (356 °F), worse than 98% of steel grades
- Difficult to machine — 15/100, worse than 98% of steel grades
- Difficult to weld — 15/100, worse than 91% of steel grades
- Limited ductility — 14%, worse than 75% of steel grades
4620 Carburized properties
Typical room-temperature values for 4620 Carburized — 10 properties are specific to this condition; the rest are grade-level values shared by every 4620 temper. Each bar shows where the value sits among the steel grades in FabDigit's library — further right is higher.
Physical3
4620 Carburized has a density of 7.85 g/cm³ (0.284 lb/in³), heavier than 56% of steel grades. It melts at 1,420°C (2,588 °F).
Mechanical13
4620 Carburized has a yield strength of 650 MPa (94.3 ksi) and a tensile strength of 850 MPa (123 ksi) — stronger than 79% of steel grades. Elongation at break is 14% and the elastic modulus is 205 GPa (29.7 Msi).
Thermal6
4620 Carburized is rated for continuous service to 180°C (356 °F). It conducts heat at 46 W/m·K (26.6 BTU/hr·ft·°F), better than 71% of steel grades. Thermal expansion is 11.9 µm/m·K (6.61 µin/in·°F).
Electrical3
4620 Carburized conducts electricity at 8 % IACS, better than 55% of steel grades.
Chemical & Environmental3
Corrosion resistance is not recommended (12/100), worse than 53% of steel grades.
Sustainability4
Producing a kilogram of 4620 Carburized takes about 29 MJ of energy and emits 2.2 kg of CO₂ — less than 53% of steel grades. Typical recycled content is 30%.
Manufacturability6
4620 Carburized's machinability is poor (15/100, worse than 98% of steel grades); weldability poor (15/100); formability good (58/100).
Values are nominal handbook figures for design screening. Certified mill or lot data ships with every FabDigit order on request.
Other 4620 tempers and conditions
4620 is also supplied in 6 other conditions. The full side-by-side table is on the 4620 overview.
- HRDefaultTake hot-rolled round or square bar as the default stock at 360 MPa yield and 163 HB when the part will be machined and then case hardened by carburizing.360 MPa yield · 163 HB
- CarburizedCarburize at 900–930 °C, quench and low-temper for the intended service state: a 58–62 HRC wear-resistant case over a tough core for gears and pins, with machining and welding then ruled out.650 MPa yield · 60 HRC
- Q&TUse direct quenching and tempering, or take these values as the core condition of a carburized part; the low carbon caps tensile near 800 MPa but keeps the core tough at 18% elongation.620 MPa yield · 23 HRC
- CDPick cold-drawn bright bar at 550 MPa yield and 192 HB for small and medium shafts machined directly to size where surface finish and dimensional accuracy matter.550 MPa yield · 192 HB
- AnnealedAnneal at about 855 °C with furnace cooling to reach 149 HB and 31.3% elongation, the easiest state for heavy machining and cold forming ahead of carburizing.372 MPa yield · 149 HB
- NormalizedNormalize at about 900 °C and air cool for uniform structure and consistent properties; this is the usual preparatory treatment before carburizing, at 366 MPa yield and 174 HB.366 MPa yield · 174 HB
Working with 4620 Carburized
Is 4620 easy to machine?
Cuts well in the annealed or normalized condition, roughly 65 % of AISI 1212, using coated carbide at moderate speeds with ample coolant. After carburizing, finish by grinding only.
Can 4620 be welded?
Weldability is acceptable for a low-carbon alloy steel; preheat 150–200 °C on heavy sections and use low-hydrogen consumables. Do not weld in carburized areas, and stress relieve after welding.
Can 4620 be formed, bent or molded?
Cold heading, cold extrusion and bending are possible in the annealed condition, while cold-drawn stock has reduced formability. Hot work at about 1100–1200 °C, finish forging no lower than 850 °C, then normalize.
What surface finishes work on 4620?
No inherent corrosion resistance — use black oxide, phosphate, zinc or nickel plating, or oil for rust protection. After carburizing and grinding, polishing or shot peening improves fatigue life.
4620 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 |
|---|---|---|
| C | 0.17 – 0.22 | 0.2 |
| Mn | 0.45 – 0.65 | 0.55 |
| Si | 0.15 – 0.35 | 0.25 |
| Ni | 1.65 – 2 | 1.82 |
| Mo | 0.2 – 0.3 | 0.25 |
| P | ≤ 0.04 | — |
| S | ≤ 0.04 | — |
| Fe | balance | — |
4620 Carburized — frequently asked
What is 4620 Carburized used for?
4620 Carburized is typically used for gears, shafts and industrial machinery parts. In short: carburizing Ni-Cr-Mo bar.
What is the yield strength of 4620 Carburized?
4620 Carburized has a typical yield strength of 650 MPa (94.3 ksi) and a tensile strength of 850 MPa (123 ksi) — stronger than 79% of steel grades. Strength varies by condition: see the 7 listed tempers.
Is 4620 Carburized easy to machine?
Not especially — machinability is rated poor (15/100, worse than 98% of steel grades). Cuts well in the annealed or normalized condition, roughly 65 % of AISI 1212, using coated carbide at moderate speeds with ample coolant. After carburizing, finish by grinding only.
Can 4620 Carburized be welded?
Not readily — weldability is rated poor (15/100). Weldability is acceptable for a low-carbon alloy steel; preheat 150–200 °C on heavy sections and use low-hydrogen consumables. Do not weld in carburized areas, and stress relieve after welding.
What surface finishes work on 4620 Carburized?
No inherent corrosion resistance — use black oxide, phosphate, zinc or nickel plating, or oil for rust protection. After carburizing and grinding, polishing or shot peening improves fatigue life.
Can 4620 Carburized be formed, bent or molded?
Cold heading, cold extrusion and bending are possible in the annealed condition, while cold-drawn stock has reduced formability. Hot work at about 1100–1200 °C, finish forging no lower than 850 °C, then normalize.
What is the maximum service temperature of 4620 Carburized?
4620 Carburized is rated for continuous use to about 180°C (356 °F). Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
What is the difference between 4620-HR and 4620-CD?
HR is the default condition — take hot-rolled round or square bar as the default stock at 360 MPa yield and 163 HB when the part will be machined and then case hardened by carburizing. CD: pick cold-drawn bright bar at 550 MPa yield and 192 HB for small and medium shafts machined directly to size where surface finish and dimensional accuracy matter. Yield strength is 360 MPa in HR versus 550 MPa in CD.
Can FabDigit make parts in 4620 Carburized?
Yes — 4620 Carburized 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
- SAE J404 — Chemical Compositions of SAE Alloy Steels — SAE International (2021)
- ASTM A29/A29M — Steel Bars, Carbon and Alloy, Hot-Wrought — ASTM (2020)
- ASM Handbook Vol.1 — Properties and Selection: Irons, Steels, and High-Performance Alloys — ASM International (1990)
- ASM Handbook Vol.4 — Heat Treating (carburizing of Ni-Mo steels) — ASM International (1991)
- Machinery's Handbook, 31st ed. — Industrial Press (2020)
- MatWeb AISI 4620 datasheet entries — MatWeb LLC (2024)
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.