Steel SUJ5 QT58-62
Hardness band
JIS SUJ5
QT58-62 = through hardened & tempered 58–62 HRC
Standard bearing hardness for raceways and rollers; the Mo addition lets this be reached in section sizes well beyond SUJ2 capability.
Values for the QT58-62 condition
Other SUJ5 tempers and conditions
SUJ5 is listed in 8 conditions; see the grade overview at SUJ5.
Compare all 8 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
ANNDefault Annealed | Standard stocking condition for bar/tube: soft spheroidized structure for turning, cold forming and ring rolling before hardening. | 410 | 660 | 22 | 197 HB | 44 W/m·K |
Hot rolled | Mill as-rolled bar or billet destined for forging and subsequent spheroidizing; too hard and lamellar for direct machining. | 560 | 950 | 12 | 32 HRC | 7.5 % IACS |
Normalized | Used to break up carbide networks and banding in heavy forged sections before spheroidizing; not a supply condition for machining. | 600 | 1,000 | 11 | 33 HRC | 7.5 % IACS |
Cold drawn | Precision-size bright bar for automatic-lathe parts and roller blanks; slightly harder and straighter than annealed hot-rolled. | 620 | 780 | 12 | 21 HRC | 8 % IACS |
QT58-62This page Through hardened & tempered 58–62 HRC | Standard bearing hardness for raceways and rollers; the Mo addition lets this be reached in section sizes well beyond SUJ2 capability. | 1,750 | 2,150 | 1 | 60 HRC | 34 W/m·K |
Hardened + dimensional-stabilizing temper | Choose when the bearing runs hot (up to ~150–200 °C) and dimensional growth from retained austenite must be suppressed. | — | 2,000 | 1.5 | 58 HRC | 35 W/m·K |
Bainite hardened | Isothermal lower-bainite treatment for large rings and shock-loaded or contaminated-lubrication bearings; more toughness and surface compressive stress at similar hardness. | — | 2,100 | 2 | 59 HRC | 35 W/m·K |
Through hardened & tempered 60–64 HRC | Maximum wear resistance and contact fatigue life for clean, low-shock applications; least tough of the hardened conditions. | — | 2,350 | 0.5 | 62 HRC | 34 W/m·K |
What is SUJ5 QT58-62?
SUJ5 QT58-62 is SUJ5 heat treated to QT58-62 — standard bearing hardness for raceways and rollers; the Mo addition lets this be reached in section sizes well beyond SUJ2 capability. SUJ5 QT58-62 has a yield strength of 1,750 MPa (254 ksi) and a tensile strength of 2,150 MPa (312 ksi) — stronger than 99% of steel grades. Elongation at break is 1% and the elastic modulus is 205 GPa (29.7 Msi). SUJ5 QT58-62 has a density of 7.81 g/cm³ (0.282 lb/in³), lighter than 84% of steel grades. It melts at 1,400°C (2,552 °F). ANN is the default condition FabDigit quotes; QT58-62 is available on request or by drawing note.
Advantages
- Polishes to a fine finish — 90/100, better than 100% of steel grades
- High strength — 1,750 MPa (254 ksi), better than 99% of steel grades
Limitations
- Difficult to machine — 5/100, worse than 100% of steel grades
- Difficult to weld — 5/100, worse than 100% of steel grades
- Limited formability — 2/100, worse than 100% of steel grades
- Limited ductility — 1%, worse than 99% of steel grades
- Limited service temperature — 150°C (302 °F), worse than 99% of steel grades
SUJ5 QT58-62 properties
Typical room-temperature values for SUJ5 QT58-62; 18 are specific to this condition. Other listed values are SUJ5 reference data and may not represent this condition. Bars are the position among steel grades.
Physical3
SUJ5 QT58-62 has a density of 7.81 g/cm³ (0.282 lb/in³), lighter than 84% of steel grades. It melts at 1,400°C (2,552 °F).
Mechanical15
SUJ5 QT58-62 has a yield strength of 1,750 MPa (254 ksi) and a tensile strength of 2,150 MPa (312 ksi) — stronger than 99% of steel grades. Elongation at break is 1% and the elastic modulus is 205 GPa (29.7 Msi).
Thermal6
SUJ5 QT58-62 is rated for continuous service to 150°C (302 °F). It conducts heat at 34 W/m·K (19.6 BTU/hr·ft·°F), worse than 77% of steel grades. Thermal expansion is 12.5 µm/m·K (6.94 µin/in·°F).
Electrical3
SUJ5 QT58-62 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 SUJ5 QT58-62 takes about 32 MJ of energy and emits 2.4 kg of CO₂ — more than 70% of steel grades. Typical recycled content is 25%.
Manufacturability8
SUJ5 QT58-62's machinability is not recommended (5/100, worse than 100% of steel grades); weldability not recommended (5/100); formability not recommended (2/100).
Values are nominal handbook figures for design screening. Confirm any required mill or lot documentation when quoting.
Working with SUJ5 QT58-62
Is SUJ5 easy to machine?
Machine only in the spheroidize-annealed condition with rigid setups and coated carbide (~30 % of AISI 1212); after hardening use CBN hard turning or grinding.
Can SUJ5 be welded?
Effectively unweldable at ~1 % C — cracks and untempered martensite are unavoidable; if a joint is unavoidable use preheat 300–400 °C, low-hydrogen filler and immediate post-weld temper.
Can SUJ5 be formed, bent or molded?
Cold heading and ring rolling need a fully spheroidized microstructure; hot forge 1050–1150 °C, finish above 900 °C and slow-cool or spheroidize immediately to avoid carbide networks and flaking.
What surface finishes work on SUJ5?
Grind and lap to raceway finishes (Ra 0.05–0.2 µm); protect the bare surface with black oxide, manganese phosphate, thin-dense chrome or oil/VCI since the alloy has essentially no corrosion resistance.
SUJ5 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 | 0.95 – 1.1 | 1.02 |
| Siraised Si improves hardenability and temper resistance | 0.4 – 0.7 | 0.55 |
| Mn | 0.9 – 1.15 | 1 |
| Cr | 0.9 – 1.2 | 1.05 |
| Modeep hardenability, distinguishes SUJ5 from SUJ3 | 0.1 – 0.25 | 0.18 |
| P | ≤ 0.03 | — |
| S | ≤ 0.03 | — |
| Cumax; Cu+Ni ≤ 0.50 | ≤ 0.25 | — |
| Ni | ≤ 0.25 | — |
| Obearing-quality total oxygen limit | ≤ 0 | — |
| Fe | balance | — |
SUJ5 QT58-62 — frequently asked
What is SUJ5 QT58-62 used for?
SUJ5 QT58-62 is typically used for very large bearing rings, heavy industrial and mill rollers, slewing ring raceways, thick-walled tapered roller cups, rolling mill backup roll bearings and large cam followers and track wheels. In short: deepest-hardening SUJ grade; for very large sections; 200 °C service limit.
What is the yield strength of SUJ5 QT58-62?
SUJ5 QT58-62 has a typical yield strength of 1,750 MPa (254 ksi) and a tensile strength of 2,150 MPa (312 ksi) — stronger than 99% of steel grades. Strength varies by condition: see the 8 listed tempers.
Is SUJ5 QT58-62 easy to machine?
Not especially — machinability is rated not recommended (5/100, worse than 100% of steel grades). Machine only in the spheroidize-annealed condition with rigid setups and coated carbide (~30 % of AISI 1212); after hardening use CBN hard turning or grinding.
Can SUJ5 QT58-62 be welded?
Not readily — weldability is rated not recommended (5/100). Effectively unweldable at ~1 % C — cracks and untempered martensite are unavoidable; if a joint is unavoidable use preheat 300–400 °C, low-hydrogen filler and immediate post-weld temper.
What surface finishes work on SUJ5 QT58-62?
Grind and lap to raceway finishes (Ra 0.05–0.2 µm); protect the bare surface with black oxide, manganese phosphate, thin-dense chrome or oil/VCI since the alloy has essentially no corrosion resistance.
Can SUJ5 QT58-62 be formed, bent or molded?
Cold heading and ring rolling need a fully spheroidized microstructure; hot forge 1050–1150 °C, finish above 900 °C and slow-cool or spheroidize immediately to avoid carbide networks and flaking.
What is the maximum service temperature of SUJ5 QT58-62?
SUJ5 QT58-62 is rated for continuous use to about 150°C (302 °F). Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
What is the difference between SUJ5-ANN and SUJ5 QT58-62?
ANN is the default condition — standard stocking condition for bar/tube: soft spheroidized structure for turning, cold forming and ring rolling before hardening. QT58-62: standard bearing hardness for raceways and rollers; the Mo addition lets this be reached in section sizes well beyond SUJ2 capability. Yield strength is 410 MPa in ANN versus 1,750 MPa in QT58-62.
Sources
- JIS G 4805 High carbon chromium bearing steels — JSA (2019)
- ASTM A485 Standard Specification for High Hardenability Antifriction Bearing Steel — ASTM (2019)
- ASM Handbook Vol.1 — Properties and Selection: Irons, Steels and High-Performance Alloys — ASM International (1990)
- ASM Handbook Vol.4 — Heat Treating (bearing steel practice) — ASM International (1991)
- Bearing steel bar datasheets (Sanyo Special Steel / Ovako / Sandvik) — various producers (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.