Steel 52100 · heat-treated state
Steel 52100 Austempered
Properties of the Austempered condition, compared with the other 52100 tempers.
Bainitic route for large or contaminated-lubrication bearings: similar hardness to martensite but higher toughness, compressive surface stress and less distortion/cracking.
What is 52100 Austempered?
52100 Austempered is 52100 heat treated to Austempered — bainitic route for large or contaminated-lubrication bearings: similar hardness to martensite but higher toughness, compressive surface stress and less distortion/cracking. 52100 Austempered has a yield strength of 1,800 MPa (261 ksi) and a tensile strength of 2,100 MPa (305 ksi) — stronger than 99% of steel grades. Elongation at break is 3% and the elastic modulus is 205 GPa (29.7 Msi). 52100 Austempered has a density of 7.81 g/cm³ (0.282 lb/in³), lighter than 84% of steel grades. It melts at 1,424°C (2,595 °F). Annealed is the default condition FabDigit quotes; Austempered is available on request or by drawing note.
Advantages
- High strength — 1,800 MPa (261 ksi), better than 99% of steel grades
- Polishes to a fine finish — 85/100, better than 99% of steel grades
Limitations
- Difficult to machine — 5/100, worse than 100% of steel grades
- Limited ductility — 3%, worse than 99% of steel grades
- Difficult to weld — 12/100, worse than 96% of steel grades
- Limited service temperature — 200°C (392 °F), worse than 93% of steel grades
52100 Austempered properties
Typical room-temperature values for 52100 Austempered — 10 properties are specific to this condition; the rest are grade-level values shared by every 52100 temper. Each bar shows where the value sits among the steel grades in FabDigit's library — further right is higher.
Physical3
52100 Austempered has a density of 7.81 g/cm³ (0.282 lb/in³), lighter than 84% of steel grades. It melts at 1,424°C (2,595 °F).
Mechanical15
52100 Austempered has a yield strength of 1,800 MPa (261 ksi) and a tensile strength of 2,100 MPa (305 ksi) — stronger than 99% of steel grades. Elongation at break is 3% and the elastic modulus is 205 GPa (29.7 Msi).
Thermal6
52100 Austempered is rated for continuous service to 200°C (392 °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
52100 Austempered conducts electricity at 7 % IACS, worse than 74% of steel grades.
Chemical & Environmental3
Corrosion resistance is not recommended (12/100), worse than 53% of steel grades.
Sustainability4
Producing a kilogram of 52100 Austempered takes about 30 MJ of energy and emits 2.2 kg of CO₂ — more than 55% of steel grades. Typical recycled content is 30%.
Manufacturability8
52100 Austempered's machinability is not recommended (5/100, worse than 100% of steel grades); weldability not recommended (12/100); formability fair (35/100).
Values are nominal handbook figures for design screening. Certified mill or lot data ships with every FabDigit order on request.
Other 52100 tempers and conditions
52100 is also supplied in 10 other conditions. The full side-by-side table is on the 52100 overview.
- AnnealedDefaultDefault stock condition for bars and tubes: soft, machinable and cold-formable, to be hardened after machining.415 MPa yield · 195 HB
- Q&T 60-64 HRCPick for gauge blocks, dies, cutting/burnishing tools and precision balls needing peak hardness; toughness is minimal.2,050 MPa yield · 62 HRC
- Q&TStandard hardened bearing condition: maximum hardness, compressive strength and rolling-contact fatigue life; grind only, keep below ~150 °C.1,900 MPa yield · 60 HRC
- Q&T 58-62 HRCNamed hardness band for balls, rollers, races and ground shafts where wear and RCF life dominate.1,850 MPa yield · 60 HRC
- AustemperedBainitic route for large or contaminated-lubrication bearings: similar hardness to martensite but higher toughness, compressive surface stress and less distortion/cracking.1,800 MPa yield · 59 HRC
- Q&T 55-58 HRCSlightly tempered-back condition for shock-loaded rollers, cams and punches needing a little more toughness than 60 HRC.1,750 MPa yield · 57 HRC
- Q&T 45-50 HRCUse when moderate hardness with usable toughness and some machinability is wanted (spacers, sleeves, tooling details).1,350 MPa yield · 48 HRC
- Cold DrawnChoose for close-tolerance shafts, pins and rollers machined to size before hardening; better surface and straightness than hot-rolled.620 MPa yield · 220 HB
Working with 52100 Austempered
Is 52100 easy to machine?
Machine in the spheroidize-annealed condition (~40 % of AISI 1212) with carbide tooling and rigid setups; once hardened above ~55 HRC use grinding, honing or CBN hard turning with 0.1–0.3 mm allowance for post-heat-treat finishing.
Can 52100 be welded?
Essentially unweldable — ~1 % C gives hard, crack-prone martensite; if unavoidable, preheat 300–400 °C, use low-hydrogen/austenitic filler and immediately post-weld temper.
Can 52100 be formed, bent or molded?
Cold ball-forming, roll-forming and tube drawing are done only from fully spheroidized stock; otherwise hot forge at 1050–1150 °C, stop above ~850 °C and slow cool then spheroidize anneal to avoid carbide networks and quench cracks.
What surface finishes work on 52100?
No corrosion resistance: protect with oil, black oxide, manganese phosphate, zinc or thin dense chrome; hardened surfaces lap and superfinish to mirror Ra <0.02 µm — avoid burning during grinding to prevent re-tempering.
52100 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; GB/T 18254 GCr15 0.95–1.05 | 0.93 – 1.05 | 1 |
| Cr | 1.35 – 1.6 | 1.45 |
| Mn | 0.25 – 0.45 | 0.35 |
| Si | 0.15 – 0.35 | 0.25 |
| P | ≤ 0.03 | — |
| S | ≤ 0.02 | — |
| Ni | ≤ 0.25 | — |
| Cu | ≤ 0.3 | — |
| Mo | ≤ 0.1 | — |
| Obearing quality: total oxygen typically ≤12 ppm | ≤ 0 | — |
| Fe | balance | — |
52100 Austempered — frequently asked
What is 52100 Austempered used for?
52100 Austempered is typically used for ball bearings, roller bearings and rollers. In short: through-hardening bearing steel.
What is the yield strength of 52100 Austempered?
52100 Austempered has a typical yield strength of 1,800 MPa (261 ksi) and a tensile strength of 2,100 MPa (305 ksi) — stronger than 99% of steel grades. Strength varies by condition: see the 11 listed tempers.
Is 52100 Austempered easy to machine?
Not especially — machinability is rated not recommended (5/100, worse than 100% of steel grades). Machine in the spheroidize-annealed condition (~40 % of AISI 1212) with carbide tooling and rigid setups; once hardened above ~55 HRC use grinding, honing or CBN hard turning with 0.1–0.3 mm allowance for post-heat-treat finishing.
Can 52100 Austempered be welded?
Not readily — weldability is rated not recommended (12/100). Essentially unweldable — ~1 % C gives hard, crack-prone martensite; if unavoidable, preheat 300–400 °C, use low-hydrogen/austenitic filler and immediately post-weld temper.
What surface finishes work on 52100 Austempered?
No corrosion resistance: protect with oil, black oxide, manganese phosphate, zinc or thin dense chrome; hardened surfaces lap and superfinish to mirror Ra <0.02 µm — avoid burning during grinding to prevent re-tempering.
Can 52100 Austempered be formed, bent or molded?
Cold ball-forming, roll-forming and tube drawing are done only from fully spheroidized stock; otherwise hot forge at 1050–1150 °C, stop above ~850 °C and slow cool then spheroidize anneal to avoid carbide networks and quench cracks.
What is the maximum service temperature of 52100 Austempered?
52100 Austempered 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.
Can FabDigit make parts in 52100 Austempered?
Yes — 52100 Austempered 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
- ASTM A295 — High-Carbon Anti-Friction Bearing Steel — ASTM International (2020)
- EN ISO 683-17 (100Cr6, 1.3505) — Ball and roller bearing steels — ISO/CEN (2014)
- GB/T 18254 (GCr15) (2016)
- JIS G 4805 (SUJ2) — High carbon chromium bearing steels — JISC (2019)
- ASM Handbook Vol.1 — Properties and Selection: Irons, Steels, and High-Performance Alloys — ASM International (1990)
- ASM Handbook Vol.16 — Machining — ASM International (1989)
- Ovako 803 / 100Cr6 bearing steel data — Ovako (2022)
- Bearing steel heat treatment and dimensional stability guidance — SKF (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.