Steel 46SiCrMo6 +U (Hot rolled)
Finish state
EN 46SiCrMo6
Cheapest mill condition for bar that will be fully austenitized and hardened by the spring maker.
Values for the +U condition
Other 46SiCrMo6 tempers and conditions
46SiCrMo6 is listed in 8 conditions; see the grade overview at 46SiCrMo6.
Compare all 8 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
Spheroidize annealed | Softest and most ductile delivery state — choose for cold heading, cold coiling and deep cold forming of torsion-bar blanks. | 430 | 710 | 18 | 210 HB | — |
Treated for high shearability | Hardness held below a shearability ceiling so bar/coil can be cold sheared or cropped without cracking the cut face. | 470 | 780 | 16 | 20 HRC | 7.5 % IACS |
Annealed | Pick for straightening, drawing, machining or cold coiling of small sections before hardening. | 500 | 800 | 15 | 22 HRC | — |
Normalized | Uniform fine ferrite-pearlite/bainite structure for stock removal, ultrasonic inspection and predictable response to later hardening. | 640 | 1,000 | 13 | 31 HRC | — |
+UThis page Hot rolled | Cheapest mill condition for bar that will be fully austenitized and hardened by the spring maker. | 650 | 1,050 | 11 | 34 HRC | 7 % IACS |
Hardened and tempered to specified core hardness | Through-hardened heavy sections (stabilizer/torsion bars) tempered to a guaranteed core hardness band, trading peak strength for reliable mid-radius properties. | 1,350 | 1,520 | 10 | 46 HRC | — |
+QTDefault Quenched and tempered | Standard service condition: oil/polymer quench from ~860–880 °C, temper 400–460 °C to 1600–2000 MPa for maximum spring fatigue and sag resistance. | 1,620 | 1,800 | 8 | 52 HRC | — |
Hardened | As-quenched martensitic state with a specified hardenability band — an intermediate stage; always temper before service because as-quenched toughness is very low. | 1,750 | 2,200 | 2 | 58 HRC | — |
What is 46SiCrMo6 +U?
46SiCrMo6 +U is 46SiCrMo6 supplied in the +U condition — cheapest mill condition for bar that will be fully austenitized and hardened by the spring maker. 46SiCrMo6 +U has a yield strength of 650 MPa (94.3 ksi) and a tensile strength of 1,050 MPa (152 ksi) — stronger than 79% of steel grades. Elongation at break is 11% and the elastic modulus is 206 GPa (29.9 Msi). 46SiCrMo6 +U has a density of 7.8 g/cm³ (0.282 lb/in³), lighter than 87% of steel grades. It melts at 1,420°C (2,588 °F). +QT is the default condition FabDigit quotes; +U is available on request or by drawing note.
Advantages
- High strength — 650 MPa (94.3 ksi), better than 79% of steel grades
Limitations
- Difficult to machine — 28/100, worse than 91% of steel grades
- Limited ductility — 11%, worse than 89% of steel grades
- Difficult to weld — 18/100, worse than 87% of steel grades
- Limited service temperature — 300°C (572 °F), worse than 78% of steel grades
- Limited formability — 22/100, worse than 76% of steel grades
46SiCrMo6 +U properties
Typical room-temperature values for 46SiCrMo6 +U; 22 are specific to this condition. Other listed values are 46SiCrMo6 reference data and may not represent this condition. Bars are the position among steel grades.
Physical3
46SiCrMo6 +U has a density of 7.8 g/cm³ (0.282 lb/in³), lighter than 87% of steel grades. It melts at 1,420°C (2,588 °F).
Mechanical16
46SiCrMo6 +U has a yield strength of 650 MPa (94.3 ksi) and a tensile strength of 1,050 MPa (152 ksi) — stronger than 79% of steel grades. Elongation at break is 11% and the elastic modulus is 206 GPa (29.9 Msi).
Thermal6
46SiCrMo6 +U is rated for continuous service to 300°C (572 °F). It conducts heat at 41 W/m·K (23.7 BTU/hr·ft·°F), worse than 62% of steel grades. Thermal expansion is 11.5 µm/m·K (6.39 µin/in·°F).
Electrical3
46SiCrMo6 +U conducts electricity at 7 % IACS, worse than 74% of steel grades.
Chemical & Environmental3
Corrosion resistance is not recommended (11/100), worse than 73% of steel grades.
Sustainability4
Producing a kilogram of 46SiCrMo6 +U takes about 30 MJ of energy and emits 2.2 kg of CO₂ — more than 56% of steel grades. Typical recycled content is 25%.
Manufacturability6
46SiCrMo6 +U's machinability is poor (28/100, worse than 91% of steel grades); weldability poor (18/100); formability poor (22/100).
Values are nominal handbook figures for design screening. Confirm any required mill or lot documentation when quoting.
Working with 46SiCrMo6 +U
Is 46SiCrMo6 easy to machine?
Machine in +A/+AC condition (carbide, 90–140 m/min); in +QT at 50+ HRC use CBN/coated carbide, rigid setups and grinding for finish — avoid grinding burn which destroys spring fatigue life.
Can 46SiCrMo6 be welded?
Not recommended for load-carrying spring joints; if unavoidable, preheat 300–350 °C, low-hydrogen consumable and immediate post-weld temper — the HAZ hardens to >55 HRC and cold-cracks readily.
Can 46SiCrMo6 be formed, bent or molded?
Hot coil at 900–1000 °C or cold coil only in +A/+AC and then harden; oil/polymer quench from 860–880 °C, temper 400–460 °C, then shot peen and pre-set (scragging) to build compressive surface stress.
What surface finishes work on 46SiCrMo6?
Shot peen, phosphate + zinc-flake or epoxy powder coating is standard; avoid acid pickling and electroplating without a 190–220 °C hydrogen bake, and protect against surface decarburization during heat treatment.
46SiCrMo6 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 |
|---|---|---|
| Cgives ~58 HRC as-quenched | 0.42 – 0.5 | 0.46 |
| Siraises temper resistance and relaxation resistance; promotes decarburization | 1.3 – 1.6 | 1.45 |
| Mn | 0.7 – 1 | 0.85 |
| Cr | 0.9 – 1.2 | 1.05 |
| Modeep hardenability for thick bars, resists temper embrittlement | 0.2 – 0.3 | 0.25 |
| P | ≤ 0.03 | — |
| S | ≤ 0.03 | — |
| Fe | balance | — |
46SiCrMo6 +U — frequently asked
What is 46SiCrMo6 +U used for?
46SiCrMo6 +U is typically used for coil springs, torsion bars and stabilizer bars. In short: highest-strength SiCrMo spring steel; 52 HRC after tempering; poor weldability and formability.
What is the yield strength of 46SiCrMo6 +U?
46SiCrMo6 +U has a typical yield strength of 650 MPa (94.3 ksi) and a tensile strength of 1,050 MPa (152 ksi) — stronger than 79% of steel grades. Strength varies by condition: see the 8 listed tempers.
Is 46SiCrMo6 +U easy to machine?
Not especially — machinability is rated poor (28/100, worse than 91% of steel grades). Machine in +A/+AC condition (carbide, 90–140 m/min); in +QT at 50+ HRC use CBN/coated carbide, rigid setups and grinding for finish — avoid grinding burn which destroys spring fatigue life.
Can 46SiCrMo6 +U be welded?
Not readily — weldability is rated poor (18/100). Not recommended for load-carrying spring joints; if unavoidable, preheat 300–350 °C, low-hydrogen consumable and immediate post-weld temper — the HAZ hardens to >55 HRC and cold-cracks readily.
What surface finishes work on 46SiCrMo6 +U?
Shot peen, phosphate + zinc-flake or epoxy powder coating is standard; avoid acid pickling and electroplating without a 190–220 °C hydrogen bake, and protect against surface decarburization during heat treatment.
Can 46SiCrMo6 +U be formed, bent or molded?
Hot coil at 900–1000 °C or cold coil only in +A/+AC and then harden; oil/polymer quench from 860–880 °C, temper 400–460 °C, then shot peen and pre-set (scragging) to build compressive surface stress.
What is the maximum service temperature of 46SiCrMo6 +U?
46SiCrMo6 +U is rated for continuous use to about 300°C (572 °F). Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
Sources
- EN 10089 — Hot-rolled steels for quenched and tempered springs: technical delivery conditions — CEN (2002)
- EN 10083-1/-3 — Steels for quenching and tempering (delivery conditions +A, +AC, +S, +N, +QT) — CEN (2006)
- EN 10027-2 — Numerical designation system for steels (material number 1.8062) — CEN (2015)
- ASM Handbook Vol.1 — Properties and Selection: Irons, Steels and High-Performance Alloys (spring steels) — ASM International (1990)
- ASM Handbook Vol.19 — Fatigue and Fracture (spring steel fatigue behaviour) — ASM International (1996)
- EN 13906-1 — Helical springs: design and calculation (E and G design values) — CEN (2013)
- Spring steel bar and wire grade datasheets (Si-Cr-Mo suspension spring steels) — Ovako / Sidenor / Gerdau special steel (2023)
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.