Steel 4150
AISI/SAE 4150 · UNS G41500 · EN 1.7228, 50CrMo4
4150 is a medium-carbon chromium-molybdenum alloy structural steel (about 0.50% C, 1% Cr, 0.2% Mo), essentially the higher-carbon version of 4140 and broadly equivalent to 50CrMo4 / 1.7228, with higher hardenability and higher attainable hardness.
Values for the HR condition
4150 tempers and conditions
4150 is supplied in 11 conditions, soft to hard. HR is the default FabDigit quotes; the values on this page are for it.
Compare all 11 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
Temper | Full anneal (~815–840 °C, furnace cool) — softest, most machinable condition and the usual delivery state for bar that will be hardened later. | 380 | 730 | 20 | 197 HB | — |
Spheroidize Annealed | Sub-critical spheroidize cycle producing globular carbides — chosen when the bar must be cold headed, deep drawn or heavily machined before hardening. | 400 | 690 | 23 | 11 HRC | 8.5 % IACS |
HRDefault Hot rolled | Standard as-rolled bar stock — cheapest starting form for parts that will be machined and then heat treated. | 520 | 860 | 16 | 21 HRC | — |
Heat Treat State | Air cooled from ~870 °C — uniform fine grain and higher strength than annealed; used to homogenize forgings before final machining or hardening. | 735 | 1,155 | 11.7 | 34 HRC | — |
Cold rolled | Cold rolled strip/flat bar — tighter thickness tolerance and smoother surface, higher strength but reduced ductility. | 760 | 950 | 9 | 28 HRC | 7.8 % IACS |
Cold drawn | Cold-drawn (usually annealed-then-drawn) bar for close size tolerance, straightness and good chip control on screw machines. | 830 | 945 | 10 | 28 HRC | 43 W/m·K |
Q&T to 28–32 HRC | Tough, readily re-machinable prehardened condition for shafts, arbors and fixtures that must not be re-heat-treated. | 860 | 965 | 18 | 30 HRC | 7.8 % IACS |
Q&T to 32–36 HRC | Common prehardened bar hardness for gears, die holders and hydraulic components needing wear resistance with machinability. | 985 | 1,100 | 16 | 34 HRC | 7.6 % IACS |
Quenched and tempered | General-purpose oil quench from ~845 °C plus ~540 °C temper — the standard commercial 'HT' condition (~302–352 HB) balancing strength and toughness. | 1,105 | 1,210 | 15 | 37 HRC | — |
Q&T to 40–44 HRC | Higher-hardness temper for wear surfaces, tool bodies and drill collars; machining now needs carbide tooling. | 1,250 | 1,380 | 12 | 42 HRC | — |
Q&T to 48–52 HRC | Low-temper, near-maximum hardness for wear parts and punches; grinding rather than turning, and notch sensitivity is high. | 1,550 | 1,720 | 10 | 50 HRC | — |
What is 4150?
4150 is a medium-carbon chromium-molybdenum alloy structural steel (about 0.50% C, 1% Cr, 0.2% Mo), essentially the higher-carbon version of 4140 and broadly equivalent to 50CrMo4 / 1.7228, with higher hardenability and higher attainable hardness. Quench and temper gives a stable 30–50 HRC with high strength and good wear resistance for shafts, gears, die holders, drill-tool joints, gun barrels and heavy-duty fasteners. Weldability is poor (preheat and post-weld temper required), cold formability is limited and there is no corrosion resistance, so coating or oiling is needed; use 4140 where weldability and toughness matter more. 4150 has a density of 7.85 g/cm³ (0.284 lb/in³), heavier than 56% of steel grades. It melts at 1,416°C (2,581 °F). 4150 has a yield strength of 520 MPa (75.4 ksi) and a tensile strength of 860 MPa (125 ksi) — stronger than 67% of steel grades. Elongation at break is 16% and the elastic modulus is 205 GPa (29.7 Msi).
What is 4150 used for?
- Gun barrels
- Axles
- Gears
Limitations
- Difficult to weld — 25/100, worse than 77% of steel grades
4150 properties
Typical room-temperature values for 4150-HR; bars are the position among steel grades.
Physical3
4150 has a density of 7.85 g/cm³ (0.284 lb/in³), heavier than 56% of steel grades. It melts at 1,416°C (2,581 °F).
Mechanical14
4150 has a yield strength of 520 MPa (75.4 ksi) and a tensile strength of 860 MPa (125 ksi) — stronger than 67% of steel grades. Elongation at break is 16% and the elastic modulus is 205 GPa (29.7 Msi).
Thermal6
4150 is rated for continuous service to 400°C (752 °F). It conducts heat at 42.6 W/m·K (24.6 BTU/hr·ft·°F), worse than 51% of steel grades. Thermal expansion is 12.3 µm/m·K (6.83 µin/in·°F).
Electrical3
4150 conducts electricity at 7.8 % IACS, worse than 57% of steel grades.
Chemical & Environmental3
Corrosion resistance is not recommended (12/100), worse than 53% of steel grades.
Sustainability4
Producing a kilogram of 4150 takes about 31 MJ of energy and emits 2.3 kg of CO₂ — more than 64% of steel grades. Typical recycled content is 30%.
Manufacturability8
4150's machinability is fair (45/100, worse than 65% of steel grades); weldability poor (25/100); formability poor (25/100).
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. 4150 is highlighted; hover a dot for its name, or open the interactive family chart.
Working with 4150
Is 4150 easy to machine?
Machine in the annealed or 28–32 HRC condition with rigid setups and carbide tooling; above 40 HRC switch to hard turning inserts or grinding.
Can 4150 be welded?
Poor weldability (CE ≈ 0.95): preheat 300–400 °C, low-hydrogen consumables, and temper/stress relieve immediately after welding to avoid HAZ cracking.
Can 4150 be formed, bent or molded?
Hot forge 1100–1200 °C and normalize afterwards; cold forming is limited to the spheroidize-annealed condition with generous bend radii.
Manufacturability
The process limits FabDigit applies to 4150. Every 4150 part is priced by an engineer; design inside these and the quote comes back without a redesign loop.
CNC machining
| Machinability | Better45 / 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 | Fair25 / 100 |
|---|---|
| Weldability | Fair25 / 100 |
4150 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 |
|---|---|---|
| CSAE J404 / AISI 4150 | 0.48 – 0.53 | 0.5 |
| Mn | 0.75 – 1 | 0.88 |
| Si | 0.15 – 0.35 | 0.25 |
| Cr | 0.8 – 1.1 | 0.95 |
| Mo | 0.15 – 0.25 | 0.2 |
| P | ≤ 0.04 | |
| Smax; 4150H/resulfurized variants differ | ≤ 0.04 | |
| Fe | balance |
What surface finishes work on 4150?
No natural corrosion resistance — use black oxide, manganese phosphate, zinc or hard chrome plating (bake to avoid hydrogen embrittlement above 40 HRC), or nitriding for wear surfaces.
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 4150 in FabDigit's catalog. Equivalence is nominal — check the exact specification when certification matters.
- UNS
- G41500
- EN / DIN / Werkstoff-Nr.
- 1.722850CrMo4
How much does 4150 cost?
4150 is a premium-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.
4150 — frequently asked
What is 4150 used for?
4150 is typically used for gun barrels, axles and gears. In short: deep-hardening toughness.
What is the yield strength of 4150?
4150 has a typical yield strength of 520 MPa (75.4 ksi) and a tensile strength of 860 MPa (125 ksi) — stronger than 67% of steel grades. Strength varies by condition: see the 11 listed tempers.
Is 4150 easy to machine?
Reasonably — machinability is rated fair (45/100, worse than 65% of steel grades). Machine in the annealed or 28–32 HRC condition with rigid setups and carbide tooling; above 40 HRC switch to hard turning inserts or grinding.
Can 4150 be welded?
Not readily — weldability is rated poor (25/100). Poor weldability (CE ≈ 0.95): preheat 300–400 °C, low-hydrogen consumables, and temper/stress relieve immediately after welding to avoid HAZ cracking.
What surface finishes work on 4150?
No natural corrosion resistance — use black oxide, manganese phosphate, zinc or hard chrome plating (bake to avoid hydrogen embrittlement above 40 HRC), or nitriding for wear surfaces.
Can 4150 be formed, bent or molded?
Hot forge 1100–1200 °C and normalize afterwards; cold forming is limited to the spheroidize-annealed condition with generous bend radii.
What is the maximum service temperature of 4150?
4150 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 4150-HR and 4150-CD?
HR is the default condition — standard as-rolled bar stock — cheapest starting form for parts that will be machined and then heat treated. CD: cold-drawn (usually annealed-then-drawn) bar for close size tolerance, straightness and good chip control on screw machines. Yield strength is 520 MPa in HR versus 830 MPa in CD.
How much does 4150 cost?
4150 is a premium-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 4150?
Yes — 4150 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)
- EN 10083-3 — Quenched and tempered steels: alloy steels (50CrMo4, 1.7228) — CEN (2006)
- ASM Handbook Vol.1 — Properties and Selection: Irons, Steels and High-Performance Alloys — ASM International (1990)
- Machinery's Handbook, 31st ed. — machinability ratings and heat treating data — Industrial Press (2020)
- Alloy bar 4150 / 50CrMo4 datasheet — Böhler / Ovako / TimkenSteel (2022)
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.