Steel 4620
AISI/SAE 4620 · UNS G46200
4620 (G46200) is a nickel-molybdenum case-hardening steel used for carburized parts that need a hard surface on a tough, ductile core.
Values for the HR condition
4620 tempers and conditions
4620 is supplied in 7 conditions, soft to hard. HR is the default FabDigit quotes; the values on this page are for it.
Compare all 7 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
HRDefault Hot rolled | 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. | 360 | 570 | 26 | 163 HB | — |
Heat Treat State | Normalize 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 | 574 | 29 | 174 HB | — |
Temper | Anneal 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 | 512 | 31.3 | 149 HB | — |
Cold rolled | Choose cold-rolled strip or sheet for close thickness tolerance and clean surface on stamped thin-wall parts carburized afterwards; yield rises to 540 MPa, elongation falls to 14%. | 540 | 640 | 14 | 11 HRC | 8 % IACS |
Cold drawn | 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. | 550 | 640 | 17 | 192 HB | 46 W/m·K |
Quenched and tempered | Use 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 | 800 | 18 | 23 HRC | — |
Carburized, Quenched & Tempered (case hardened) | 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. | 650 | 850 | 14 | 60 HRC | — |
What is 4620?
4620 (G46200) is a nickel-molybdenum case-hardening steel used for carburized parts that need a hard surface on a tough, ductile core. It is widely stocked as hot-rolled, cold-rolled, cold-drawn, annealed, normalized, Q&T and carburized bar for gear and shaft blanks, with the default condition at 360 MPa yield, 570 MPa tensile, 26 % elongation and 163 HB. Machinability is about 65 % of AISI 1212 in the annealed or normalized state, but after carburizing the part can only be ground. It has no corrosion resistance; 8620 is the usual alternative carburizing grade. 4620 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). 4620 has a yield strength of 360 MPa (52.2 ksi) and a tensile strength of 570 MPa (82.7 ksi) — weaker than 72% of steel grades. Elongation at break is 26% and the elastic modulus is 205 GPa (29.7 Msi).
What is 4620 used for?
- Gears
- Shafts
- Industrial machinery parts
Advantages
- Ductile — tolerates forming and impact — 26%, better than 82% of steel grades
4620 properties
Typical room-temperature values for 4620-HR; bars are the position among steel grades.
Physical3
4620 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 has a yield strength of 360 MPa (52.2 ksi) and a tensile strength of 570 MPa (82.7 ksi) — weaker than 72% of steel grades. Elongation at break is 26% and the elastic modulus is 205 GPa (29.7 Msi).
Thermal6
4620 is rated for continuous service to 400°C (752 °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 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 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's machinability is good (57/100, better than 71% of steel grades); weldability good (65/100); formability good (58/100).
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. 4620 is highlighted; hover a dot for its name, or open the interactive family chart.
Working with 4620
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.
Manufacturability
The process limits FabDigit applies to 4620. Every 4620 part is priced by an engineer; design inside these and the quote comes back without a redesign loop.
CNC machining
| Machinability | Better57 / 100 |
|---|---|
| ISO material group | P.2 |
| Cutting speed (rough / finish) | 180 / 210 m/min |
| Minimum wall | 0.8 mm |
| Minimum internal radius | 1 mm |
| Drill depth limit | 5× diameter |
| Best surface (machined / polished) | Ra 1.6 / — |
| Hardenable after machining | No |
Sheet metal
| Formability | Better58 / 100 |
|---|---|
| Weldability | Better65 / 100 |
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 |
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.
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 4620 in FabDigit's catalog. Equivalence is nominal — check the exact specification when certification matters.
- UNS
- G46200
How much does 4620 cost?
4620 is a standard-cost steel ($$), cheaper than about 71% 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.
4620 — frequently asked
What is 4620 used for?
4620 is typically used for gears, shafts and industrial machinery parts. In short: carburizing Ni-Cr-Mo bar.
What is the yield strength of 4620?
4620 has a typical yield strength of 360 MPa (52.2 ksi) and a tensile strength of 570 MPa (82.7 ksi) — weaker than 72% of steel grades. Strength varies by condition: see the 7 listed tempers.
Is 4620 easy to machine?
Reasonably — machinability is rated good (57/100, better than 71% 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 be welded?
Yes — weldability is rated good (65/100). 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?
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 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?
4620 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 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.
How much does 4620 cost?
4620 is a standard-cost steel ($$), cheaper than about 71% 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 4620?
Yes — 4620 is available for CNC machining and sheet metal; every part is priced by an engineer rather than instantly. 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; 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.