Steel 5155-CD (Cold drawn)
Supply condition
AISI/SAE 5155 · UNS G51550
Close-tolerance bright bar and spring wire feedstock; work-hardened, needs stress relief or full hardening.
Values for the CD condition
Other 5155 tempers and conditions
5155 is listed in 8 conditions; see the grade overview at 5155.
Compare all 8 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
full anneal ~815 °C, slow cool | Softest condition for machining, cold forming or coiling before hardening. | 410 | 720 | 22 | 205 HB | — |
Hot rolled | Cheapest mill condition for parts that will be hot formed and then quenched and tempered. | 530 | 900 | 17 | 25 HRC | 8 % IACS |
~870 °C, air cool | Uniform pearlitic structure for stock removal and pre-hardening machining of larger sections. | 600 | 960 | 18 | 27 HRC | — |
CDThis page Cold drawn | Close-tolerance bright bar and spring wire feedstock; work-hardened, needs stress relief or full hardening. | 760 | 900 | 11 | 27 HRC | 8 % IACS |
oil quenched, tempered ~650 °C | High-toughness, readily machinable temper when spring action is not required. | 820 | 950 | 20 | 30 HRC | — |
oil quenched, tempered ~540 °C | Tougher, lower-strength temper for shafts, torsion bars and shock-loaded machine parts. | 1,090 | 1,210 | 15 | 38 HRC | — |
QT 44-48 HRCDefault oil quenched ~855 °C, tempered ~425 °C (spring temper) | Standard delivered condition for coil, leaf and torsion springs — best balance of fatigue strength and toughness. | 1,420 | 1,600 | 10 | 46 HRC | — |
oil quenched, tempered 205–315 °C | Maximum strength for highly loaded small springs and wear parts; low toughness, notch sensitive. | 1,700 | 1,930 | 8 | 52 HRC | — |
What is 5155-CD?
5155-CD is 5155 supplied in the CD condition — close-tolerance bright bar and spring wire feedstock; work-hardened, needs stress relief or full hardening. 5155-CD has a yield strength of 760 MPa (110 ksi) and a tensile strength of 900 MPa (131 ksi) — stronger than 85% of steel grades. Elongation at break is 11% and the elastic modulus is 205 GPa (29.7 Msi). 5155-CD 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). QT 44-48 HRC is the default condition FabDigit quotes; CD is available on request or by drawing note.
Advantages
- High strength — 760 MPa (110 ksi), better than 85% of steel grades
- Polishes to a fine finish — 65/100, better than 78% of steel grades
Limitations
- Limited ductility — 11%, worse than 89% of steel grades
- Difficult to weld — 20/100, worse than 84% of steel grades
- Limited service temperature — 300°C (572 °F), worse than 78% of steel grades
5155-CD properties
Typical room-temperature values for 5155-CD; 23 are specific to this condition. Other listed values are 5155 reference data and may not represent this condition. Bars are the position among steel grades.
Physical3
5155-CD 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
5155-CD has a yield strength of 760 MPa (110 ksi) and a tensile strength of 900 MPa (131 ksi) — stronger than 85% of steel grades. Elongation at break is 11% and the elastic modulus is 205 GPa (29.7 Msi).
Thermal6
5155-CD is rated for continuous service to 300°C (572 °F). It conducts heat at 46 W/m·K (26.6 BTU/hr·ft·°F), better than 71% of steel grades. Thermal expansion is 12.3 µm/m·K (6.83 µin/in·°F).
Electrical3
5155-CD conducts electricity at 8 % IACS, better than 55% of steel grades.
Chemical & Environmental3
Corrosion resistance is not recommended (12/100), worse than 53% of steel grades.
Sustainability4
Producing a kilogram of 5155-CD takes about 30 MJ of energy and emits 2.3 kg of CO₂ — more than 56% of steel grades. Typical recycled content is 30%.
Manufacturability7
5155-CD's machinability is fair (50/100, worse than 53% of steel grades); weldability poor (20/100); formability poor (25/100).
Values are nominal handbook figures for design screening. Confirm any required mill or lot documentation when quoting.
Working with 5155-CD
Is 5155 easy to machine?
Machine in the annealed or ≤32 HRC tempered condition with carbide tooling and rigid setups; above 45 HRC use grinding, CBN or hard-turning.
Can 5155 be welded?
Poor weldability — 0.55 %C plus Cr gives martensitic HAZ; if unavoidable use low-hydrogen consumables, 250–350 °C preheat and immediate post-weld temper, and never weld a finished spring.
Can 5155 be formed, bent or molded?
Cold coil only from annealed/drawn wire with generous bend radii; hot form at 900–1050 °C, then oil quench from 830–870 °C and temper 380–480 °C for spring properties.
What surface finishes work on 5155?
Shot peen highly stressed springs for fatigue life, then phosphate + oil, powder coat, or zinc plate with a 190–220 °C hydrogen-relief bake to avoid embrittlement.
5155 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 | 0.51 – 0.59 | 0.55 |
| Mn | 0.7 – 0.9 | 0.8 |
| Si | 0.15 – 0.35 | 0.25 |
| Cr | 0.7 – 0.9 | 0.8 |
| Pmax, bar/billet | ≤ 0.04 | — |
| Smax, bar/billet | ≤ 0.04 | — |
| Fe | balance | — |
5155-CD — frequently asked
What is 5155-CD used for?
5155-CD is typically used for coil springs, leaf springs and clutch parts. In short: high-fatigue spring steel; 1600 MPa tempered strength; not weldable as finished spring.
What is the yield strength of 5155-CD?
5155-CD has a typical yield strength of 760 MPa (110 ksi) and a tensile strength of 900 MPa (131 ksi) — stronger than 85% of steel grades. Strength varies by condition: see the 8 listed tempers.
Is 5155-CD easy to machine?
Reasonably — machinability is rated fair (50/100, worse than 53% of steel grades). Machine in the annealed or ≤32 HRC tempered condition with carbide tooling and rigid setups; above 45 HRC use grinding, CBN or hard-turning.
Can 5155-CD be welded?
Not readily — weldability is rated poor (20/100). Poor weldability — 0.55 %C plus Cr gives martensitic HAZ; if unavoidable use low-hydrogen consumables, 250–350 °C preheat and immediate post-weld temper, and never weld a finished spring.
What surface finishes work on 5155-CD?
Shot peen highly stressed springs for fatigue life, then phosphate + oil, powder coat, or zinc plate with a 190–220 °C hydrogen-relief bake to avoid embrittlement.
Can 5155-CD be formed, bent or molded?
Cold coil only from annealed/drawn wire with generous bend radii; hot form at 900–1050 °C, then oil quench from 830–870 °C and temper 380–480 °C for spring properties.
What is the maximum service temperature of 5155-CD?
5155-CD 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 5155 QT 44-48 HRC and 5155-HR?
QT 44-48 HRC is the default condition — standard delivered condition for coil, leaf and torsion springs — best balance of fatigue strength and toughness. HR: cheapest mill condition for parts that will be hot formed and then quenched and tempered. Yield strength is 1,420 MPa in QT 44-48 HRC versus 530 MPa in HR.
Sources
- SAE J404 — Chemical Compositions of SAE Alloy Steels — SAE International (2021)
- ASTM A689 — Carbon and Alloy Steel Bars for Springs — ASTM (2021)
- GB/T 1222 — (55CrMnA) — SAC (2016)
- EN 10089 — Hot rolled steels for quenched and tempered springs (55Cr3) — CEN (2002)
- ASM Handbook Vol.1 — Properties and Selection: Irons, Steels — ASM International (1990)
- ASM Handbook Vol.19 — Fatigue and Fracture — ASM International (1996)
- Machinery's Handbook, 31st ed. — Industrial Press (2020)
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.