Steel 51100 QT 45-50 HRC
Hardness band
AISI/SAE 51100 · ASTM A295
Tougher tempered condition for shafts, cams and wear parts where shock loading matters more than peak hardness.
Values for the QT 45-50 HRC condition
Other 51100 tempers and conditions
51100 is listed in 7 conditions; see the grade overview at 51100.
- Annealed
- Normalized
- HR
- CD
- QT 45-50 HRC
- QT 58-62 HRC
- QT 60-64 HRC
Compare all 7 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
AnnealedDefault Annealed (spheroidize annealed bar/tube) | Standard mill-supplied condition for machining, cold forming and subsequent through hardening. | 400 | 640 | 25 | 192 HB | 46 W/m·K |
Normalized (≈870 °C, air cooled) | Used to break up carbide networks in forgings before spheroidize annealing. | 520 | 900 | 12 | 26 HRC | 8 % IACS |
Hot rolled | As-rolled bar for forging or re-heat-treatment stock; hard and unsuitable for direct machining. | 550 | 900 | 12 | 27 HRC | 8 % IACS |
Cold drawn | Close-tolerance bright bar and wire for rollers, pins and cold-headed blanks. | 620 | 760 | 10 | 19 HRC | 8 % IACS |
QT 45-50 HRCThis page quench + temper 300–400 °C | Tougher tempered condition for shafts, cams and wear parts where shock loading matters more than peak hardness. | 1,400 | 1,600 | 5 | 48 HRC | — |
oil quench + temper 180–230 °C | Slightly softer temper for better dimensional stability and impact tolerance in service to ~200 °C. | 1,700 | 2,050 | 2 | 60 HRC | — |
oil quench + low temper (150–180 °C) | Standard through-hardened bearing condition for maximum rolling-contact fatigue life and wear resistance. | 1,800 | 2,200 | 1 | 62 HRC | 36 W/m·K |
What is 51100 QT 45-50 HRC?
51100 QT 45-50 HRC is 51100 heat treated to QT 45-50 HRC — tougher tempered condition for shafts, cams and wear parts where shock loading matters more than peak hardness. 51100 QT 45-50 HRC has a yield strength of 1,400 MPa (203 ksi) and a tensile strength of 1,600 MPa (232 ksi) — stronger than 96% of steel grades. Elongation at break is 5% and the elastic modulus is 205 GPa (29.7 Msi). 51100 QT 45-50 HRC has a density of 7.81 g/cm³ (0.282 lb/in³), lighter than 84% of steel grades. It melts at 1,415°C (2,579 °F). Annealed is the default condition FabDigit quotes; QT 45-50 HRC is available on request or by drawing note.
Advantages
- Polishes to a fine finish — 88/100, better than 100% of steel grades
- High strength — 1,400 MPa (203 ksi), better than 96% of steel grades
Limitations
- Limited ductility — 5%, worse than 98% of steel grades
- Low fracture toughness — 28 MPa·√m (25.5 ksi·√in), worse than 97% of steel grades
- Difficult to machine — 18/100, worse than 97% of steel grades
- Difficult to weld — 12/100, worse than 96% of steel grades
- Limited service temperature — 280°C (536 °F), worse than 82% of steel grades
51100 QT 45-50 HRC properties
Typical room-temperature values for 51100 QT 45-50 HRC; 12 are specific to this condition. Other listed values are 51100 reference data and may not represent this condition. Bars are the position among steel grades.
Physical3
51100 QT 45-50 HRC has a density of 7.81 g/cm³ (0.282 lb/in³), lighter than 84% of steel grades. It melts at 1,415°C (2,579 °F).
Mechanical16
51100 QT 45-50 HRC has a yield strength of 1,400 MPa (203 ksi) and a tensile strength of 1,600 MPa (232 ksi) — stronger than 96% of steel grades. Elongation at break is 5% and the elastic modulus is 205 GPa (29.7 Msi).
Thermal6
51100 QT 45-50 HRC is rated for continuous service to 280°C (536 °F). It conducts heat at 46 W/m·K (26.6 BTU/hr·ft·°F), better than 71% of steel grades. Thermal expansion is 11.9 µm/m·K (6.61 µin/in·°F).
Electrical3
51100 QT 45-50 HRC conducts electricity at 8 % IACS, better than 55% of steel grades.
Chemical & Environmental3
Corrosion resistance is not recommended (10/100), worse than 86% of steel grades.
Sustainability4
Producing a kilogram of 51100 QT 45-50 HRC takes about 34 MJ of energy and emits 2.4 kg of CO₂ — more than 82% of steel grades. Typical recycled content is 25%.
Manufacturability8
51100 QT 45-50 HRC's machinability is poor (18/100, worse than 97% of steel grades); weldability not recommended (12/100); formability fair (40/100).
Values are nominal handbook figures for design screening. Confirm any required mill or lot documentation when quoting.
Working with 51100 QT 45-50 HRC
Is 51100 easy to machine?
Machine only in the spheroidize-annealed condition (~40 % of AISI 1212) with rigid setups and carbide tooling; hardened parts require grinding, honing or CBN hard turning.
Can 51100 be welded?
Effectively non-weldable in production — ~1 % C causes quench cracking; if repair is unavoidable, preheat 300–400 °C and post-weld temper immediately.
Can 51100 be formed, bent or molded?
Cold heading and upsetting are done spheroidize-annealed; hot forge 1050–1150 °C, finish above 900 °C and slow-cool then re-anneal to avoid carbide networks.
What surface finishes work on 51100?
Harden at 800–840 °C in oil, temper 150–180 °C, then grind and superfinish; protect with oil film, black oxide, manganese phosphate or thin dense chrome since the alloy has no inherent corrosion resistance.
51100 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 |
|---|---|---|
| CASTM A295 grade 51100 | 0.98 – 1.1 | 1.03 |
| Mn | 0.25 – 0.45 | 0.35 |
| Si | 0.15 – 0.35 | 0.25 |
| Crleaner than 52100 (1.30–1.60 Cr) | 0.9 – 1.15 | 1.02 |
| P | ≤ 0.03 | — |
| S | ≤ 0.02 | — |
| Niresidual max | ≤ 0.25 | — |
| Curesidual max | ≤ 0.3 | — |
| Moresidual max | ≤ 0.1 | — |
| Fe | balance | — |
51100 QT 45-50 HRC — frequently asked
What is 51100 QT 45-50 HRC used for?
51100 QT 45-50 HRC is typically used for small to medium bearing races, precision rollers, bearing balls, cam followers and track rollers, pump and gear shafts requiring high hardness and bushings and thrust washers. In short: lower-Cr 52100 alternative; ASTM A295 bearing grade; hardens 45–64 HRC.
What is the yield strength of 51100 QT 45-50 HRC?
51100 QT 45-50 HRC has a typical yield strength of 1,400 MPa (203 ksi) and a tensile strength of 1,600 MPa (232 ksi) — stronger than 96% of steel grades. Strength varies by condition: see the 7 listed tempers.
Is 51100 QT 45-50 HRC easy to machine?
Not especially — machinability is rated poor (18/100, worse than 97% of steel grades). Machine only in the spheroidize-annealed condition (~40 % of AISI 1212) with rigid setups and carbide tooling; hardened parts require grinding, honing or CBN hard turning.
Can 51100 QT 45-50 HRC be welded?
Not readily — weldability is rated not recommended (12/100). Effectively non-weldable in production — ~1 % C causes quench cracking; if repair is unavoidable, preheat 300–400 °C and post-weld temper immediately.
What surface finishes work on 51100 QT 45-50 HRC?
Harden at 800–840 °C in oil, temper 150–180 °C, then grind and superfinish; protect with oil film, black oxide, manganese phosphate or thin dense chrome since the alloy has no inherent corrosion resistance.
Can 51100 QT 45-50 HRC be formed, bent or molded?
Cold heading and upsetting are done spheroidize-annealed; hot forge 1050–1150 °C, finish above 900 °C and slow-cool then re-anneal to avoid carbide networks.
What is the maximum service temperature of 51100 QT 45-50 HRC?
51100 QT 45-50 HRC is rated for continuous use to about 280°C (536 °F). Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
What is the difference between 51100 Annealed and 51100-CD?
Annealed is the default condition — standard mill-supplied condition for machining, cold forming and subsequent through hardening. CD: close-tolerance bright bar and wire for rollers, pins and cold-headed blanks. Yield strength is 400 MPa in Annealed versus 620 MPa in CD.
Sources
- ASTM A295/A295M — High-Carbon Anti-Friction Bearing Steel — ASTM International (2014)
- ASM Handbook Vol. 1: Properties and Selection — Irons, Steels, and High-Performance Alloys — ASM International (1990)
- ASM Handbook Vol. 4: Heat Treating — ASM International (1991)
- Machining Data Handbook / ASM Machining volume — ASM International (1989)
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.