Steel 55Cr3 · heat-treated state
Steel 55Cr3 Hardened & Tempered
Properties of the Hardened & Tempered condition, compared with the other 55Cr3 tempers.
Pick when maximum load capacity / sag resistance is needed in coil springs and small torsion elements; toughness and hydrogen sensitivity worsen.
What is 55Cr3 Hardened & Tempered?
55Cr3 Hardened & Tempered is 55Cr3 heat treated to Hardened & Tempered — pick when maximum load capacity / sag resistance is needed in coil springs and small torsion elements; toughness and hydrogen sensitivity worsen. 55Cr3 Hardened & Tempered has a yield strength of 1,600 MPa (232 ksi) and a tensile strength of 1,800 MPa (261 ksi) — stronger than 98% of steel grades. Elongation at break is 6% and the elastic modulus is 206 GPa (29.9 Msi). 55Cr3 Hardened & Tempered 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). Annealed is the default condition FabDigit quotes; Hardened & Tempered is available on request or by drawing note.
Advantages
- High strength — 1,600 MPa (232 ksi), better than 98% of steel grades
Limitations
- Difficult to weld — 5/100, worse than 100% of steel grades
- Difficult to machine — 12/100, worse than 99% of steel grades
- Limited formability — 5/100, worse than 99% of steel grades
- Limited ductility — 6%, worse than 98% of steel grades
- Limited service temperature — 200°C (392 °F), worse than 93% of steel grades
55Cr3 Hardened & Tempered properties
Typical room-temperature values for 55Cr3 Hardened & Tempered — 15 properties are specific to this condition; the rest are grade-level values shared by every 55Cr3 temper. Each bar shows where the value sits among the steel grades in FabDigit's library — further right is higher.
Physical3
55Cr3 Hardened & Tempered 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).
Mechanical13
55Cr3 Hardened & Tempered has a yield strength of 1,600 MPa (232 ksi) and a tensile strength of 1,800 MPa (261 ksi) — stronger than 98% of steel grades. Elongation at break is 6% and the elastic modulus is 206 GPa (29.9 Msi).
Thermal6
55Cr3 Hardened & Tempered is rated for continuous service to 200°C (392 °F). It conducts heat at 44 W/m·K (25.4 BTU/hr·ft·°F), better than 57% of steel grades. Thermal expansion is 12.5 µm/m·K (6.94 µin/in·°F).
Electrical2
55Cr3 Hardened & Tempered has an electrical resistivity of 2.2×10⁻⁷ Ω·m.
Chemical & Environmental2
Corrosion resistance is not recommended (10/100), worse than 87% of steel grades.
Sustainability4
Producing a kilogram of 55Cr3 Hardened & Tempered takes about 26 MJ of energy and emits 2 kg of CO₂ — less than 64% of steel grades. Typical recycled content is 30%.
Manufacturability7
55Cr3 Hardened & Tempered's machinability is not recommended (12/100, worse than 99% of steel grades); weldability not recommended (5/100); formability not recommended (5/100).
Values are nominal handbook figures for design screening. Certified mill or lot data ships with every FabDigit order on request.
Other 55Cr3 tempers and conditions
55Cr3 is also supplied in 8 other conditions. The full side-by-side table is on the 55Cr3 overview.
- AnnealedDefaultStock condition for machining, cold forming and pre-heat-treat blanks; hardness capped at 248 HB by EN 10089.480 MPa yield · 225 HB
- Hardened & TemperedPick when maximum load capacity / sag resistance is needed in coil springs and small torsion elements; toughness and hydrogen sensitivity worsen.1,600 MPa yield · 50 HRC
- Q&TStandard service condition for leaf springs, stabiliser bars and torsion bars: austenitise ~850 °C, oil quench, temper 400–480 °C.1,450 MPa yield · 46 HRC
- CH1.7176 bar supplied heat treated to a specified core hardness band, giving uniform medium-high strength for further machining or induction/case work.550 MPa yield · 25 HRC
- S1.7176 annealed to a capped hardness so that bar and coil can be cold sheared/cropped cleanly before forming and hardening.430 MPa yield · 215 HB
- AC1.7176 annealed to globular carbides — the softest delivery state, used for cold heading, cold extrusion and heavy machining before hardening.380 MPa yield · 190 HB
Working with 55Cr3 Hardened & Tempered
Is 55Cr3 easy to machine?
Machine in the annealed (+A) state with rigid setups and carbide tooling; at 45–50 HRC only grinding, hard turning with CBN or EDM is practical.
Can 55Cr3 be welded?
Effectively unweldable for structural use (Ceq ≈ 0.85); if unavoidable, preheat 300–350 °C, low-hydrogen consumables and immediate post-weld temper, then re-heat-treat.
Can 55Cr3 be formed, bent or molded?
Coil and bend hot (850–1050 °C) or in the annealed condition; harden from ~840–860 °C in oil and temper 400–480 °C, then stress-relieve set springs at ~250–300 °C.
What surface finishes work on 55Cr3?
Always shot-peen loaded surfaces for fatigue life; protect by phosphate + epoxy/powder paint or zinc-rich coating — avoid acid pickling and standard electroplating without a 190–210 °C hydrogen bake-out.
55Cr3 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 |
|---|---|---|
| CEN 10089 | 0.52 – 0.59 | 0.55 |
| Si | 0.15 – 0.4 | 0.25 |
| Mn | 0.7 – 1 | 0.85 |
| Cr | 0.7 – 1 | 0.85 |
| P | ≤ 0.03 | — |
| S | ≤ 0.03 | — |
| Fe | balance | — |
55Cr3 Hardened & Tempered — frequently asked
What is 55Cr3 Hardened & Tempered used for?
55Cr3 Hardened & Tempered is typically used for leaf springs, heavy coil springs, torsion bars, stabiliser (anti-roll) bars, spring clips and retainers and agricultural tine springs. In short: spring chromium bar.
What is the yield strength of 55Cr3 Hardened & Tempered?
55Cr3 Hardened & Tempered has a typical yield strength of 1,600 MPa (232 ksi) and a tensile strength of 1,800 MPa (261 ksi) — stronger than 98% of steel grades. Strength varies by condition: see the 9 listed tempers.
Is 55Cr3 Hardened & Tempered easy to machine?
Not especially — machinability is rated not recommended (12/100, worse than 99% of steel grades). Machine in the annealed (+A) state with rigid setups and carbide tooling; at 45–50 HRC only grinding, hard turning with CBN or EDM is practical.
Can 55Cr3 Hardened & Tempered be welded?
Not readily — weldability is rated not recommended (5/100). Effectively unweldable for structural use (Ceq ≈ 0.85); if unavoidable, preheat 300–350 °C, low-hydrogen consumables and immediate post-weld temper, then re-heat-treat.
What surface finishes work on 55Cr3 Hardened & Tempered?
Always shot-peen loaded surfaces for fatigue life; protect by phosphate + epoxy/powder paint or zinc-rich coating — avoid acid pickling and standard electroplating without a 190–210 °C hydrogen bake-out.
Can 55Cr3 Hardened & Tempered be formed, bent or molded?
Coil and bend hot (850–1050 °C) or in the annealed condition; harden from ~840–860 °C in oil and temper 400–480 °C, then stress-relieve set springs at ~250–300 °C.
What is the maximum service temperature of 55Cr3 Hardened & Tempered?
55Cr3 Hardened & Tempered is rated for continuous use to about 200°C (392 °F). Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
What is the difference between 55Cr3 Annealed and 55Cr3-AC?
Annealed is the default condition — stock condition for machining, cold forming and pre-heat-treat blanks; hardness capped at 248 HB by EN 10089. AC: 1.7176 annealed to globular carbides — the softest delivery state, used for cold heading, cold extrusion and heavy machining before hardening. Yield strength is 480 MPa in Annealed versus 380 MPa in AC.
Can FabDigit make parts in 55Cr3 Hardened & Tempered?
Yes — 55Cr3 Hardened & Tempered is available for CNC machining and sheet metal with instant online pricing. Upload a STEP file to get a price and a DFM check.
Sources
- EN 10089 — Hot rolled steels for quenched and tempered springs — CEN (2002)
- SAE J404 / J1397 — Chemical compositions and mechanical properties of SAE alloy steels (5155) — SAE International (2009)
- GB/T 1222 (2016)
- ASM Handbook Vol.1: Properties and Selection — Irons, Steels, and High-Performance Alloys — ASM International (1990)
- Spring Design Manual (HS-795) — SAE International (1996)
- Spring steel bar and flat bar grade data (55Cr3 / 1.7176) — European long-products mills (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.