Steel 46Si7
EN 46Si7
46Si7 (1.5024) is a silicon-alloyed spring steel with higher carbon than 38Si7, hardened and tempered to about 1250 MPa yield, 1420 MPa tensile and 420 HB (45 HRC).
Reference datasheet — 46Si7 is not in the instant-quote catalog. Upload your part and an engineer will quote it in this grade or suggest the closest stocked equivalent.
Values for the +QT condition
46Si7 tempers and conditions
46Si7 is supplied in 9 conditions, soft to hard. +QT is the default FabDigit quotes; the values on this page are for it.
Compare all 9 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
Spheroidize annealed | Choose for cold heading, cold extrusion or deep cold forming of the bar/wire before hardening. | 370 | 620 | 24 | 190 HB | — |
Treated for high shearability | Order when coil or bar must be cold-sheared/cropped into blanks without cracked or torn cut faces. | 390 | 660 | 22 | 14 HRC | 7 % IACS |
Annealed | Pick for bar/coil that will be machined, straightened or coiled cold before the final hardening and tempering. | 400 | 680 | 20 | 210 HB | — |
Supplied to specified hardenability band | Use when the part is hardened by the buyer and a guaranteed Jominy end-quench band is required for repeatable through-hardening. | 480 | 800 | 16 | 60 HRC | 6.5 % IACS |
Restricted (narrowed) hardenability band for core properties | Order for heavy sections or safety parts where a narrow, reproducible core-hardness scatter after quenching is mandatory. | 480 | 800 | 16 | 22 HRC | 6 % IACS |
Normalized | Intermediate condition for grain refinement after hot forging, before final Q&T. | 520 | 850 | 14 | 25 HRC | 6.5 % IACS |
Cold drawn | Bright bar or spring wire with close tolerance and raised strength for parts finished without further hardening or lightly stress-relieved only. | 750 | 900 | 8 | 27 HRC | 6 % IACS |
+QTDefault Quenched and tempered | Standard delivery/finish condition for springs and highly stressed elastic parts; oil hardened ~860 °C and tempered 400–500 °C to 41–48 HRC. | 1,250 | 1,420 | 8 | 45 HRC | — |
Oil hardened and tempered spring wire/strip | Pre-hardened wire/strip coiled directly into springs and only stress-relieved afterwards; highest strength and fatigue level of this grade. | 1,420 | 1,600 | 7 | 48 HRC | — |
What is 46Si7?
46Si7 (1.5024) is a silicon-alloyed spring steel with higher carbon than 38Si7, hardened and tempered to about 1250 MPa yield, 1420 MPa tensile and 420 HB (45 HRC). Engineers select it when a spring needs more elastic strength than 38Si7 at similar cost; it is supplied as flat and round bar, and as pre-tempered (OT) wire for coiling. Trade-offs are 8 % elongation, low formability, a 250 °C service limit, no corrosion resistance and poor weldability at CEV of roughly 0.75. Step up to 56Si7 for higher fatigue and elastic strength, or 51CrV4 for larger hardened sections. 46Si7 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). 46Si7 has a yield strength of 1,250 MPa (181 ksi) and a tensile strength of 1,420 MPa (206 ksi) — stronger than 95% of steel grades. Elongation at break is 8% and the elastic modulus is 206 GPa (29.9 Msi).
What is 46Si7 used for?
- leaf springs
- coil springs
- torsion bars
Advantages
- High strength — 1,250 MPa (181 ksi), better than 95% of steel grades
Limitations
- Limited formability — 8/100, worse than 97% of steel grades
- Limited ductility — 8%, worse than 95% of steel grades
- Difficult to machine — 25/100, worse than 93% of steel grades
- Difficult to weld — 15/100, worse than 91% of steel grades
- Low fracture toughness — 45 MPa·√m (41 ksi·√in), worse than 90% of steel grades
46Si7 properties
Typical room-temperature values for 46Si7-+QT; bars are the position among steel grades.
Physical3
46Si7 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
46Si7 has a yield strength of 1,250 MPa (181 ksi) and a tensile strength of 1,420 MPa (206 ksi) — stronger than 95% of steel grades. Elongation at break is 8% and the elastic modulus is 206 GPa (29.9 Msi).
Thermal6
46Si7 is rated for continuous service to 250°C (482 °F). It conducts heat at 44 W/m·K (25.4 BTU/hr·ft·°F), better than 57% of steel grades. Thermal expansion is 11.5 µm/m·K (6.39 µin/in·°F).
Electrical3
46Si7 conducts electricity at 6 % IACS, worse than 78% of steel grades.
Chemical & Environmental3
Corrosion resistance is not recommended (11/100), worse than 73% of steel grades.
Sustainability4
Producing a kilogram of 46Si7 takes about 29 MJ of energy and emits 2.2 kg of CO₂ — less than 53% of steel grades. Typical recycled content is 35%.
Manufacturability7
46Si7's machinability is poor (25/100, worse than 93% of steel grades); weldability poor (15/100); formability not recommended (8/100).
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. 46Si7 is highlighted; hover a dot for its name, or open the interactive family chart.
Working with 46Si7
Is 46Si7 easy to machine?
Machine in +A/+AC condition with carbide tooling; at 45 HRC after Q&T only grinding, hard turning with CBN or EDM is practical.
Can 46Si7 be welded?
Poor weldability (CEV ≈ 0.75) — avoid on spring parts; if unavoidable preheat 250–350 °C, low-hydrogen consumables and post-weld temper, accepting loss of spring properties in the HAZ.
Can 46Si7 be formed, bent or molded?
Cold-form or coil in the spheroidized/annealed condition or use pre-tempered OT wire; hot forge 1050–850 °C, then normalize or anneal before hardening; austenitize ~850–870 °C, oil quench, temper 400–500 °C.
46Si7 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 | 0.42 – 0.5 | 0.46 |
| Simain strengthening element, raises elastic limit | 1.5 – 1.8 | 1.65 |
| Mn | 0.5 – 0.8 | 0.65 |
| P | ≤ 0.03 | |
| S | ≤ 0.03 | |
| Crresidual/optional max | ≤ 0.4 | |
| Fe | balance |
What surface finishes work on 46Si7?
Shot-peen springs for fatigue life, then phosphate + oil, zinc or zinc-nickel plating with 190–220 °C hydrogen-relief bake, or e-coat; guard against decarburization and surface graphitization during heat treatment.
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).
Organic Coating
Black / Phosphate
Thermal Spray
Equivalent designations
Standards and trade names that resolve to Steel 46Si7 in FabDigit's catalog. Equivalence is nominal — check the exact specification when certification matters.
- EN / DIN / Werkstoff-Nr.
- 1.5024
How much does 46Si7 cost?
46Si7 is a budget-cost steel ($), cheaper than about 90% 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.
46Si7 — frequently asked
What is 46Si7 used for?
46Si7 is typically used for leaf springs, coil springs and torsion bars. In short: higher strength than 38Si7; 45 HRC after Q&T; cold form only when annealed.
What is the yield strength of 46Si7?
46Si7 has a typical yield strength of 1,250 MPa (181 ksi) and a tensile strength of 1,420 MPa (206 ksi) — stronger than 95% of steel grades. Strength varies by condition: see the 9 listed tempers.
Is 46Si7 easy to machine?
Not especially — machinability is rated poor (25/100, worse than 93% of steel grades). Machine in +A/+AC condition with carbide tooling; at 45 HRC after Q&T only grinding, hard turning with CBN or EDM is practical.
Can 46Si7 be welded?
Not readily — weldability is rated poor (15/100). Poor weldability (CEV ≈ 0.75) — avoid on spring parts; if unavoidable preheat 250–350 °C, low-hydrogen consumables and post-weld temper, accepting loss of spring properties in the HAZ.
What surface finishes work on 46Si7?
Shot-peen springs for fatigue life, then phosphate + oil, zinc or zinc-nickel plating with 190–220 °C hydrogen-relief bake, or e-coat; guard against decarburization and surface graphitization during heat treatment.
Can 46Si7 be formed, bent or molded?
Cold-form or coil in the spheroidized/annealed condition or use pre-tempered OT wire; hot forge 1050–850 °C, then normalize or anneal before hardening; austenitize ~850–870 °C, oil quench, temper 400–500 °C.
What is the maximum service temperature of 46Si7?
46Si7 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 46Si7 +QT and 46Si7-OT?
+QT is the default condition — standard delivery/finish condition for springs and highly stressed elastic parts; oil hardened ~860 °C and tempered 400–500 °C to 41–48 HRC. OT: pre-hardened wire/strip coiled directly into springs and only stress-relieved afterwards; highest strength and fatigue level of this grade. Yield strength is 1,250 MPa in +QT versus 1,420 MPa in OT.
How much does 46Si7 cost?
46Si7 is a budget-cost steel ($), cheaper than about 90% 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.
Sources
- EN 10089 — Hot-rolled steels for quenched and tempered springs — CEN (2002)
- DIN 17221 — Heat-treatable steels for springs — DIN (1988)
- EN 10083-1 — Steels for quenching and tempering, general technical delivery conditions (+A, +AC, +S, +H, +QT designations) — CEN (2006)
- Stahlschlüssel / Key to Steel — Verlag Stahlschlüssel Wegst (2019)
- ASM Handbook Vol.1 — Properties and Selection: Irons, Steels, and High-Performance Alloys (spring steels) — ASM International (1990)
- 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; 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.