Steel SUJ5
JIS SUJ5
SUJ5 is a high-carbon chromium bearing steel to JIS G 4805 carrying the highest chromium and molybdenum levels of the SUJ series, which gives the deepest hardenability in the group.
Reference datasheet — SUJ5 is not in the instant-quote catalog. Upload your part and an engineer will quote it in this grade or suggest the closest stocked equivalent.
Values for the ANN condition
SUJ5 tempers and conditions
SUJ5 is supplied in 8 conditions, soft to hard. ANN is the default FabDigit quotes; the values on this page are for it.
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 |
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?
SUJ5 is a high-carbon chromium bearing steel to JIS G 4805 carrying the highest chromium and molybdenum levels of the SUJ series, which gives the deepest hardenability in the group. Engineers use it for the largest bearing cross-sections; it ships as annealed, normalized, hot-rolled or cold-drawn bar and tube at about 660 MPa tensile, 410 MPa yield, 22 % elongation and 197 HB, then is quenched and tempered to 58–64 HRC. Maximum service temperature is about 200 °C, it is effectively unweldable at roughly 1 % C, and bare surfaces have essentially no corrosion resistance. SUJ2 is the lower-cost choice for thinner sections. SUJ5 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). SUJ5 has a yield strength of 410 MPa (59.5 ksi) and a tensile strength of 660 MPa (95.7 ksi) — weaker than 57% of steel grades. Elongation at break is 22% and the elastic modulus is 210 GPa (30.5 Msi).
What is SUJ5 used for?
- Very large bearing rings
- Heavy industrial and mill rollers
- Slewing ring raceways
- Thick-walled tapered roller cups
- Rolling mill backup roll bearings
- Large cam followers and track wheels
- Heavy-duty thrust washers
Advantages
- Polishes to a fine finish — 85/100, better than 99% of steel grades
Limitations
- Difficult to weld — 5/100, worse than 100% of steel grades
- Limited service temperature — 200°C (392 °F), worse than 93% of steel grades
- Difficult to machine — 40/100, worse than 77% of steel grades
SUJ5 properties
Typical room-temperature values for SUJ5-ANN; bars are the position among steel grades.
Physical3
SUJ5 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 has a yield strength of 410 MPa (59.5 ksi) and a tensile strength of 660 MPa (95.7 ksi) — weaker than 57% of steel grades. Elongation at break is 22% and the elastic modulus is 210 GPa (30.5 Msi).
Thermal6
SUJ5 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).
Electrical3
SUJ5 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 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's machinability is fair (40/100, worse than 77% of steel grades); weldability not recommended (5/100); formability fair (35/100).
Common Calculations5
Values are nominal handbook figures for design screening. Certified mill or lot data ships with every FabDigit order on request.
Strength versus weight in the steel family
Yield strength against density for every steel grade FabDigit runs. SUJ5 is highlighted; hover a dot for its name, or open the interactive family chart.
Working with SUJ5
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.
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 |
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.
Surface treatments FabDigit runs on steel parts — pick them in the quote configurator or call them out on the drawing. Each links to its datasheet in the surface-finish library (thickness, specs, call-out, material verdicts).
Organic Coating
Black / Phosphate
Thermal Spray
How much does SUJ5 cost?
SUJ5 is a budget-cost steel ($), cheaper than about 90% of the materials FabDigit quotes. Part price depends far more on geometry, tolerance and quantity than on the raw stock — upload a CAD file for a live quote.
SUJ5 — frequently asked
What is SUJ5 used for?
SUJ5 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?
SUJ5 has a typical yield strength of 410 MPa (59.5 ksi) and a tensile strength of 660 MPa (95.7 ksi) — weaker than 57% of steel grades. Strength varies by condition: see the 8 listed tempers.
Is SUJ5 easy to machine?
Not especially — machinability is rated fair (40/100, worse than 77% 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 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?
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 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?
SUJ5 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 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.
How much does SUJ5 cost?
SUJ5 is a budget-cost steel ($), cheaper than about 90% of the materials FabDigit quotes. Part price depends far more on geometry, tolerance and quantity than on the raw stock — upload a CAD file for a live quote.
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; hardness values on non-Brinell scales are converted approximately for charting only. Manufacturability limits are FabDigit quote-engine defaults and may be relaxed by engineering review. Nothing on this page is a certification — request mill certs, CoC or material test reports with your order.