Steel 6150
AISI/SAE 6150 · UNS G61500 · EN 1.7166, 50CrV4 · JIS SUP10 · GB 50CrVA
6150 (G61500, 50CrV4, 1.8159, 50CrVA) is a high-carbon chromium-vanadium spring steel; vanadium refines the grain and raises hardenability, giving high fatigue strength and toughness after quench and temper.
Values for the HR condition
6150 tempers and conditions
6150 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 |
|---|---|---|---|---|---|---|
Spheroidize annealed | Pick for maximum cold formability of strip/wire before hardening (cold heading, deep drawing). | 400 | 640 | 25 | 11 HRC | 8.2 % IACS |
full/soft anneal ~800–830 °C, slow cool | Softest and most machinable condition; choose for heavy machining, cold forming or as the delivery state before hardening. | 415 | 670 | 22 | 197 HB | 46 W/m·K |
Cold rolled | Precision-thickness strip for blanking and forming of flat springs, hardened after forming. | 560 | 780 | 12 | 20 HRC | 7.8 % IACS |
HRDefault Hot rolled | Standard stocked mill condition for bars and flats that will be machined and then heat treated by the user. | 600 | 950 | 16 | 25 HRC | — |
~870–900 °C, air cool | Uniform fine-grained structure for stable machining and a good starting point for hardening of forgings. | 615 | 940 | 21 | 27 HRC | — |
Cold drawn | Close-tolerance bright bar with raised yield strength; use where little or no further machining is needed. | 750 | 900 | 10 | 26 HRC | 7.8 % IACS |
Quenched and high-temperature tempered | Tough, machinable hardened state for shafts and moderately loaded parts. | 830 | 1,000 | 15 | 32 HRC | 7.6 % IACS |
Quenched and tempered | General-purpose hardened spring/torsion-bar condition balancing high elastic limit with usable toughness. | 1,100 | 1,300 | 10 | 40 HRC | — |
Quenched and tempered ~400–450 °C | High elastic-limit condition for heavy leaf springs, torsion bars and hand tools. | 1,350 | 1,500 | 8 | 46 HRC | — |
Oil-hardened and tempered spring wire | Ready-to-coil hardened-and-tempered wire for valve springs and dynamically loaded coil springs; strength falls with increasing diameter. | 1,450 | 1,650 | 7 | 48 HRC | 7.4 % IACS |
Quenched and low-temperature tempered ~200–250 °C | Maximum hardness/wear condition for chisels, punches and cutting edges; low toughness, notch-sensitive. | 1,650 | 1,850 | 7 | 52 HRC | — |
What is 6150?
6150 (G61500, 50CrV4, 1.8159, 50CrVA) is a high-carbon chromium-vanadium spring steel; vanadium refines the grain and raises hardenability, giving high fatigue strength and toughness after quench and temper. It is stocked as hot-rolled, cold-rolled and cold-drawn bar in annealed, normalized, spheroidized and Q&T conditions to 50–54 HRC, plus oil-tempered spring wire. Default Q&T values are about 600 MPa yield, 950 MPa tensile, 16 % elongation and 255 HB, with service to 400 °C. Weldability is poor (C≈0.50, CE>0.8) and there is no corrosion resistance, so plating or paint is required. 6150 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). 6150 has a yield strength of 600 MPa (87 ksi) and a tensile strength of 950 MPa (138 ksi) — stronger than 77% of steel grades. Elongation at break is 16% and the elastic modulus is 207 GPa (30 Msi).
What is 6150 used for?
- Springs
- Bolts
- Stamped tool blanks
Advantages
- High strength — 600 MPa (87 ksi), better than 77% of steel grades
6150 properties
Typical room-temperature values for 6150-HR; bars are the position among steel grades.
Physical3
6150 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
6150 has a yield strength of 600 MPa (87 ksi) and a tensile strength of 950 MPa (138 ksi) — stronger than 77% of steel grades. Elongation at break is 16% and the elastic modulus is 207 GPa (30 Msi).
Thermal6
6150 is rated for continuous service to 400°C (752 °F). It conducts heat at 44 W/m·K (25.4 BTU/hr·ft·°F), better than 57% of steel grades. Thermal expansion is 12.3 µm/m·K (6.83 µin/in·°F).
Electrical3
6150 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 6150 takes about 30 MJ of energy and emits 2.2 kg of CO₂ — more than 56% of steel grades. Typical recycled content is 35%.
Manufacturability8
6150's machinability is fair (45/100, worse than 65% of steel grades); weldability poor (28/100); formability fair (35/100).
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. 6150 is highlighted; hover a dot for its name, or open the interactive family chart.
Working with 6150
Is 6150 easy to machine?
Machine in the annealed or ≤32 HRC condition with rigid setups, carbide tooling and 30–40 % lower speeds than 1045; above 45 HRC grind or use CBN.
Can 6150 be welded?
Poor weldability (C≈0.50, CE>0.8): avoid on springs; if unavoidable, preheat 300–350 °C, low-hydrogen consumables and temper immediately after welding.
Can 6150 be formed, bent or molded?
Cold form only in the annealed/spheroidized state; hot forge 1100–850 °C then normalize, and coil springs hot or from pre-tempered (OT) wire.
Manufacturability
The process limits FabDigit applies to 6150. Every 6150 part is priced by an engineer; design inside these and the quote comes back without a redesign loop.
CNC machining
| Machinability | Fair45 / 100 |
|---|---|
| ISO material group | P.4 |
| Cutting speed (rough / finish) | 160 / 190 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 / — |
| Hardenable after machining | No |
Sheet metal
| Formability | Better35 / 100 |
|---|---|
| Weldability | Fair28 / 100 |
6150 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 |
|---|---|---|
| CAISI 6150 0.48–0.53; EN 50CrV4 0.47–0.55 | 0.47 – 0.55 | 0.5 |
| Si | 0.15 – 0.4 | 0.25 |
| MnAISI 0.70–0.90 | 0.5 – 0.9 | 0.8 |
| Cr | 0.8 – 1.2 | 1 |
| VAISI 6150 V min 0.15 | 0.1 – 0.25 | 0.17 |
| P | ≤ 0.03 | |
| Smax (AISI allows 0.040) | ≤ 0.03 | |
| Niresidual | ≤ 0.35 | |
| Curesidual | ≤ 0.25 | |
| Fe | balance |
What surface finishes work on 6150?
No corrosion resistance — phosphate + oil, zinc or Zn-Ni plating (bake to avoid hydrogen embrittlement), or paint/powder coat; shot peen springs to boost 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 6150 in FabDigit's catalog. Equivalence is nominal — check the exact specification when certification matters.
How much does 6150 cost?
6150 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.
6150 — frequently asked
What is 6150 used for?
6150 is typically used for springs, bolts and stamped tool blanks. In short: chromium-vanadium spring bar.
What is the yield strength of 6150?
6150 has a typical yield strength of 600 MPa (87 ksi) and a tensile strength of 950 MPa (138 ksi) — stronger than 77% of steel grades. Strength varies by condition: see the 11 listed tempers.
Is 6150 easy to machine?
Reasonably — machinability is rated fair (45/100, worse than 65% of steel grades). Machine in the annealed or ≤32 HRC condition with rigid setups, carbide tooling and 30–40 % lower speeds than 1045; above 45 HRC grind or use CBN.
Can 6150 be welded?
Not readily — weldability is rated poor (28/100). Poor weldability (C≈0.50, CE>0.8): avoid on springs; if unavoidable, preheat 300–350 °C, low-hydrogen consumables and temper immediately after welding.
What surface finishes work on 6150?
No corrosion resistance — phosphate + oil, zinc or Zn-Ni plating (bake to avoid hydrogen embrittlement), or paint/powder coat; shot peen springs to boost fatigue life.
Can 6150 be formed, bent or molded?
Cold form only in the annealed/spheroidized state; hot forge 1100–850 °C then normalize, and coil springs hot or from pre-tempered (OT) wire.
What is the maximum service temperature of 6150?
6150 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 6150-HR and 6150-OT?
HR is the default condition — standard stocked mill condition for bars and flats that will be machined and then heat treated by the user. OT: ready-to-coil hardened-and-tempered wire for valve springs and dynamically loaded coil springs; strength falls with increasing diameter. Yield strength is 600 MPa in HR versus 1,450 MPa in OT.
How much does 6150 cost?
6150 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 6150?
Yes — 6150 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
- ASTM A29/A29M – Standard Specification for General Requirements for Steel Bars, Carbon and Alloy, Hot-Wrought — ASTM (2020)
- SAE J404 – Chemical Compositions of SAE Alloy Steels — SAE International (2009)
- EN 10089 – Hot rolled steels for quenched and tempered springs — CEN (2002)
- EN 10083-3 – Steels for quenching and tempering: alloy steels — CEN (2006)
- GB/T 1222 – (Spring steels) — SAC (2016)
- EN 10270-2 – Steel wire for mechanical springs: oil hardened and tempered wire — CEN (2011)
- ASM Handbook Vol.1 – Properties and Selection: Irons, Steels, and High-Performance Alloys — ASM International (1990)
- ASM Handbook Vol.4 – Heat Treating — ASM International (1991)
- Low-alloy spring steel property tables (50CrV4 / 1.7166) — Stahlschlüssel / Key to Steel (2019)
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.