Steel 60SiCr8 QT-48
Hardness band · default condition
EN 60SiCr8 · JIS SUP12 · GB 60Si2CrA
QT-48 = q&T 46–50 HRC
The normal working condition for coil and suspension springs — best balance of strength, relaxation resistance and toughness.
Values for the QT-48 condition
Other 60SiCr8 tempers and conditions
60SiCr8 is listed in 9 conditions; see the grade overview at 60SiCr8.
Compare all 9 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
Solution annealed | Softest supply condition for machining, cold coiling of heavy bar, or upsetting before hardening. | 480 | 800 | 16 | 235 HB | — |
Normalized | Grain-refined intermediate condition used after hot forming and before final hardening. | 620 | 1,000 | 12 | 30 HRC | 5.6 % IACS |
Hot rolled | Mill supply condition for leaf-spring and bar stock that will be hot formed and then quenched and tempered. | 650 | 1,050 | 11 | 31 HRC | 5.5 % IACS |
Cold drawn | Close-tolerance bright bar or pre-drawn wire for machining and subsequent hardening. | 780 | 950 | 8 | 29 HRC | 5.4 % IACS |
Q&T 42–46 HRC | Choose when impact toughness and shot-blast tolerance matter more than maximum stress, e.g. leaf springs and torsion bars. | 1,300 | 1,450 | 10 | 44 HRC | — |
QT-48DefaultThis page Q&T 46–50 HRC | The normal working condition for coil and suspension springs — best balance of strength, relaxation resistance and toughness. | 1,550 | 1,750 | 8 | 48 HRC | — |
Q&T + stress relieved and shot peened spring | Finished-spring condition: compressive surface residual stress raises fatigue limit substantially over the as-tempered state. | 1,550 | 1,750 | 8 | 48 HRC | 5.2 % IACS |
Q&T 50–54 HRC | Maximum stress capacity for small-section, highly stressed springs; accept low ductility and high notch/decarburization sensitivity. | 1,750 | 1,950 | 6 | 52 HRC | — |
oil hardened and tempered valve-spring wire (EN 10270-2 VDSiCr type) | Continuously oil-hardened-and-tempered clean-steel wire for valve and high-cycle suspension springs; highest strength and cleanliness class. | 1,850 | 2,050 | 6 | 54 HRC | — |
What is 60SiCr8 QT-48?
60SiCr8 QT-48 is 60SiCr8 heat treated to QT-48 — the normal working condition for coil and suspension springs — best balance of strength, relaxation resistance and toughness. 60SiCr8 QT-48 has a yield strength of 1,550 MPa (225 ksi) and a tensile strength of 1,750 MPa (254 ksi) — stronger than 97% of steel grades. Elongation at break is 8% and the elastic modulus is 206 GPa (29.9 Msi). 60SiCr8 QT-48 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).
Advantages
- High strength — 1,550 MPa (225 ksi), better than 97% of steel grades
Limitations
- Difficult to machine — 15/100, worse than 98% of steel grades
- Low fracture toughness — 30 MPa·√m (27.3 ksi·√in), worse than 96% of steel grades
- Difficult to weld — 12/100, worse than 96% of steel grades
- Limited ductility — 8%, worse than 95% of steel grades
- Limited formability — 10/100, worse than 95% of steel grades
60SiCr8 QT-48 properties
Typical room-temperature values for 60SiCr8 QT-48; 13 are specific to this condition. Other listed values are 60SiCr8 reference data and may not represent this condition. Bars are the position among steel grades.
Physical3
60SiCr8 QT-48 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).
Mechanical16
60SiCr8 QT-48 has a yield strength of 1,550 MPa (225 ksi) and a tensile strength of 1,750 MPa (254 ksi) — stronger than 97% of steel grades. Elongation at break is 8% and the elastic modulus is 206 GPa (29.9 Msi).
Thermal6
60SiCr8 QT-48 is rated for continuous service to 250°C (482 °F). It conducts heat at 30 W/m·K (17.3 BTU/hr·ft·°F), worse than 83% of steel grades. Thermal expansion is 11.5 µm/m·K (6.39 µin/in·°F).
Electrical3
60SiCr8 QT-48 conducts electricity at 5.2 % IACS, worse than 81% of steel grades.
Chemical & Environmental3
Corrosion resistance is not recommended (12/100), worse than 53% of steel grades.
Sustainability4
Producing a kilogram of 60SiCr8 QT-48 takes about 30 MJ of energy and emits 2.1 kg of CO₂ — more than 56% of steel grades. Typical recycled content is 30%.
Manufacturability5
60SiCr8 QT-48's machinability is poor (15/100, worse than 98% of steel grades); weldability not recommended (12/100); formability not recommended (10/100).
Common Calculations5
Values are nominal handbook figures for design screening. Confirm any required mill or lot documentation when quoting.
Working with 60SiCr8 QT-48
Is 60SiCr8 easy to machine?
Machine in the spheroidize-annealed state (≈235 HB) with coated carbide; above 45 HRC use grinding or CBN only, and keep decarburized skin off spring surfaces.
Can 60SiCr8 be welded?
Effectively non-weldable for spring duty (C ≈ 0.60 %, high Si); if unavoidable, preheat 300–400 °C, low-hydrogen consumables and re-quench/temper the joint.
Can 60SiCr8 be formed, bent or molded?
Cold coil in annealed or oil-tempered wire condition; heavy sections hot form at 900–1050 °C, then austenitize 860–900 °C, oil quench and temper 400–480 °C for 45–50 HRC.
What surface finishes work on 60SiCr8?
Shot peen springs after stress relief for fatigue life; protect with zinc-flake, phosphate+oil or powder coat — avoid acid pickling and electroplating without post-bake due to hydrogen embrittlement risk.
60SiCr8 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 | 0.55 – 0.65 | 0.6 |
| SiGB 60Si2CrA uses 1.40–1.80 % | 1.6 – 2.1 | 1.85 |
| Mn | 0.6 – 1 | 0.8 |
| CrGB 60Si2CrA and JIS SUP12 run 0.60–1.00 % Cr | 0.2 – 0.45 | 0.3 |
| P | ≤ 0.03 | — |
| S | ≤ 0.03 | — |
| Curesidual, max | ≤ 0.2 | — |
| Fe | balance | — |
60SiCr8 QT-48 — frequently asked
What is 60SiCr8 QT-48 used for?
60SiCr8 QT-48 is typically used for valve springs, suspension coil springs and clutch springs. In short: high sag resistance; valve-spring quality steel; not a fabrication steel.
What is the yield strength of 60SiCr8 QT-48?
60SiCr8 QT-48 has a typical yield strength of 1,550 MPa (225 ksi) and a tensile strength of 1,750 MPa (254 ksi) — stronger than 97% of steel grades. Strength varies by condition: see the 9 listed tempers.
Is 60SiCr8 QT-48 easy to machine?
Not especially — machinability is rated poor (15/100, worse than 98% of steel grades). Machine in the spheroidize-annealed state (≈235 HB) with coated carbide; above 45 HRC use grinding or CBN only, and keep decarburized skin off spring surfaces.
Can 60SiCr8 QT-48 be welded?
Not readily — weldability is rated not recommended (12/100). Effectively non-weldable for spring duty (C ≈ 0.60 %, high Si); if unavoidable, preheat 300–400 °C, low-hydrogen consumables and re-quench/temper the joint.
What surface finishes work on 60SiCr8 QT-48?
Shot peen springs after stress relief for fatigue life; protect with zinc-flake, phosphate+oil or powder coat — avoid acid pickling and electroplating without post-bake due to hydrogen embrittlement risk.
Can 60SiCr8 QT-48 be formed, bent or molded?
Cold coil in annealed or oil-tempered wire condition; heavy sections hot form at 900–1050 °C, then austenitize 860–900 °C, oil quench and temper 400–480 °C for 45–50 HRC.
What is the maximum service temperature of 60SiCr8 QT-48?
60SiCr8 QT-48 is rated for continuous use to about 250°C (482 °F). Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
What is the difference between 60SiCr8 QT-48 and 60SiCr8-A?
QT-48 is the default condition — the normal working condition for coil and suspension springs — best balance of strength, relaxation resistance and toughness. A: softest supply condition for machining, cold coiling of heavy bar, or upsetting before hardening. Yield strength is 1,550 MPa in QT-48 versus 480 MPa in A.
Sources
- EN 10089 — Hot rolled steels for quenched and tempered springs — CEN (2002)
- EN 10270-2 — Steel wire for mechanical springs: oil hardened and tempered spring steel wire — CEN (2011)
- GB/T 1222 — (60Si2CrA) — SAC (2016)
- JIS G 4801 — Spring steels (SUP12) — JISC (2011)
- ASM Handbook Vol.1 — Properties and Selection: Irons, Steels, and High-Performance Alloys — ASM International (1990)
- ASM Handbook Vol.19 — Fatigue and Fracture — ASM International (1996)
- EN 13906-1 — Cylindrical helical springs, design and calculation — CEN (2013)
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.