Steel 46Si7 +CH
Heat-treated state
EN 46Si7
+CH = 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.
Values for the +CH condition
Other 46Si7 tempers and conditions
46Si7 is listed in 9 conditions; see the grade overview at 46Si7.
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 |
+CHThis page 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 +CH?
46Si7 +CH is 46Si7 heat treated to +CH — order for heavy sections or safety parts where a narrow, reproducible core-hardness scatter after quenching is mandatory. 46Si7 +CH has a yield strength of 480 MPa (69.6 ksi) and a tensile strength of 800 MPa (116 ksi) — stronger than 59% of steel grades. Elongation at break is 16% and the elastic modulus is 206 GPa (29.9 Msi). 46Si7 +CH 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; +CH is available on request or by drawing note.
Limitations
- Limited service temperature — 300°C (572 °F), worse than 78% of steel grades
- Low electrical conductivity — 6 % IACS, worse than 78% of steel grades
46Si7 +CH properties
Typical room-temperature values for 46Si7 +CH; 23 are specific to this condition. Other listed values are 46Si7 reference data and may not represent this condition. Bars are the position among steel grades.
Physical3
46Si7 +CH 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 +CH has a yield strength of 480 MPa (69.6 ksi) and a tensile strength of 800 MPa (116 ksi) — stronger than 59% of steel grades. Elongation at break is 16% and the elastic modulus is 206 GPa (29.9 Msi).
Thermal6
46Si7 +CH is rated for continuous service to 300°C (572 °F). It conducts heat at 45 W/m·K (26 BTU/hr·ft·°F), better than 66% of steel grades. Thermal expansion is 11.5 µm/m·K (6.39 µin/in·°F).
Electrical3
46Si7 +CH 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 +CH 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 +CH's machinability is fair (45/100, worse than 65% of steel grades); weldability poor (30/100); formability poor (30/100).
Values are nominal handbook figures for design screening. Confirm any required mill or lot documentation when quoting.
Working with 46Si7 +CH
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.
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.
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 | — |
46Si7 +CH — frequently asked
What is 46Si7 +CH used for?
46Si7 +CH 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 +CH?
46Si7 +CH has a typical yield strength of 480 MPa (69.6 ksi) and a tensile strength of 800 MPa (116 ksi) — stronger than 59% of steel grades. Strength varies by condition: see the 9 listed tempers.
Is 46Si7 +CH easy to machine?
Reasonably — machinability is rated fair (45/100, worse than 65% 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 +CH be welded?
Not readily — weldability is rated poor (30/100). 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 +CH?
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 +CH 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 +CH?
46Si7 +CH 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.
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.
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. Nothing on this page is a certification — request mill certs, CoC or material test reports with your order.