Steel 6150-SA (Spheroidize annealed)
Heat-treated state
AISI/SAE 6150 · UNS G61500 · EN 1.7166, 50CrV4 · JIS SUP10 · GB 50CrVA
Pick for maximum cold formability of strip/wire before hardening (cold heading, deep drawing).
Values for the SA condition
Other 6150 tempers and conditions
6150 is listed in 11 conditions; see the grade overview at 6150.
Compare all 11 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
SAThis page 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-SA?
6150-SA is 6150 heat treated to SA — pick for maximum cold formability of strip/wire before hardening (cold heading, deep drawing). 6150-SA has a yield strength of 400 MPa (58 ksi) and a tensile strength of 640 MPa (92.8 ksi) — weaker than 60% of steel grades. Elongation at break is 25% and the elastic modulus is 207 GPa (30 Msi). 6150-SA 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). HR is the default condition FabDigit quotes; SA is available on request or by drawing note.
Advantages
- Forms and bends easily — 62/100, better than 78% of steel grades
- Ductile — tolerates forming and impact — 25%, better than 77% of steel grades
6150-SA properties
Typical room-temperature values for 6150-SA; 23 are specific to this condition. Other listed values are 6150 reference data and may not represent this condition. Bars are the position among steel grades.
Physical3
6150-SA 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-SA has a yield strength of 400 MPa (58 ksi) and a tensile strength of 640 MPa (92.8 ksi) — weaker than 60% of steel grades. Elongation at break is 25% and the elastic modulus is 207 GPa (30 Msi).
Thermal6
6150-SA 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 12.3 µm/m·K (6.83 µin/in·°F).
Electrical3
6150-SA conducts electricity at 8.2 % IACS, better than 61% of steel grades.
Chemical & Environmental3
Corrosion resistance is not recommended (12/100), worse than 53% of steel grades.
Sustainability4
Producing a kilogram of 6150-SA 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-SA's machinability is good (56/100, better than 71% of steel grades); weldability fair (35/100); formability good (62/100).
Values are nominal handbook figures for design screening. Confirm any required mill or lot documentation when quoting.
Working with 6150-SA
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.
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.
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 | — |
6150-SA — frequently asked
What is 6150-SA used for?
6150-SA is typically used for springs, bolts and stamped tool blanks. In short: chromium-vanadium spring bar.
What is the yield strength of 6150-SA?
6150-SA has a typical yield strength of 400 MPa (58 ksi) and a tensile strength of 640 MPa (92.8 ksi) — weaker than 60% of steel grades. Strength varies by condition: see the 11 listed tempers.
Is 6150-SA easy to machine?
Reasonably — machinability is rated good (56/100, better than 71% 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-SA be welded?
With care — weldability is rated fair (35/100). 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-SA?
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-SA 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-SA?
6150-SA 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.
Can FabDigit make parts in 6150-SA?
Yes — 6150-SA 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. Nothing on this page is a certification — request mill certs, CoC or material test reports with your order.