Steel SUJ1 Annealed
Temper · default condition
JIS SUJ1
Standard stock condition for machining, cold forming and turning of rings/rollers before hardening.
Values for the Annealed condition
Other SUJ1 tempers and conditions
SUJ1 is listed in 9 conditions; see the grade overview at SUJ1.
Compare all 9 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
AnnealedDefaultThis page spheroidize annealed (soft, as-supplied bar/tube) | Standard stock condition for machining, cold forming and turning of rings/rollers before hardening. | 400 | 660 | 22 | 190 HB | 46 W/m·K |
Hot rolled | Mill as-rolled condition, usually only an intermediate before spheroidizing; hard, low-ductility pearlite. | 550 | 950 | 12 | 29 HRC | — |
Normalized | Used to break up carbide networks in forgings before spheroidizing; not a delivery condition for machining. | 600 | 1,000 | 10 | 31 HRC | 6.2 % IACS |
Cold drawn | Choose for close-tolerance bright bar or seamless bearing tube going straight into automatic-lathe machining. | 620 | 780 | 12 | 235 HB | — |
Induction hardened | Use on larger sections where SUJ1's limited hardenability prevents through hardening: hard raceway surface, tougher core. | 950 | 1,100 | 6 | 60 HRC | 5.6 % IACS |
quenched and tempered ~250 °C (dimensionally stabilized) | Stabilized temper for parts running at 150–200 °C or needing tight long-term dimensional stability. | 1,650 | 1,950 | 2 | 57 HRC | — |
Martempered / austempered | Bainitic or martempered route chosen to cut quench distortion and raise toughness/compressive residual stress in thin rings. | 1,700 | 2,050 | 2 | 58 HRC | 6 % IACS |
oil quenched from ~820–840 °C, tempered 150–180 °C | Standard service condition for balls, rollers and small rings in light/medium-duty bearings up to ~120 °C. | 1,800 | 2,200 | 1 | 60 HRC | 36 W/m·K |
oil quenched, tempered ~150 °C (maximum hardness) | Pick for maximum wear resistance and indentation strength on small sections; lowest toughness of the range. | 1,950 | 2,400 | 0.5 | 62 HRC | — |
What is SUJ1 Annealed?
SUJ1 Annealed is SUJ1 in the Annealed temper — standard stock condition for machining, cold forming and turning of rings/rollers before hardening. SUJ1 Annealed has a yield strength of 400 MPa (58 ksi) and a tensile strength of 660 MPa (95.7 ksi) — weaker than 60% of steel grades. Elongation at break is 22% and the elastic modulus is 210 GPa (30.5 Msi). SUJ1 Annealed 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).
Advantages
- Polishes to a fine finish — 80/100, better than 97% of steel grades
Limitations
- Limited service temperature — 150°C (302 °F), worse than 99% of steel grades
- Difficult to weld — 12/100, worse than 96% of steel grades
- Low electrical conductivity — 6.5 % IACS, worse than 77% of steel grades
SUJ1 Annealed properties
Typical room-temperature values for SUJ1 Annealed; 14 are specific to this condition. Other listed values are SUJ1 reference data and may not represent this condition. Bars are the position among steel grades.
Physical3
SUJ1 Annealed 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
SUJ1 Annealed has a yield strength of 400 MPa (58 ksi) and a tensile strength of 660 MPa (95.7 ksi) — weaker than 60% of steel grades. Elongation at break is 22% and the elastic modulus is 210 GPa (30.5 Msi).
Thermal6
SUJ1 Annealed is rated for continuous service to 150°C (302 °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
SUJ1 Annealed conducts electricity at 6.5 % IACS, worse than 77% of steel grades.
Chemical & Environmental3
Corrosion resistance is not recommended (12/100), worse than 53% of steel grades.
Sustainability4
Producing a kilogram of SUJ1 Annealed takes about 29 MJ of energy and emits 2.1 kg of CO₂ — less than 53% of steel grades. Typical recycled content is 25%.
Manufacturability8
SUJ1 Annealed's machinability is fair (42/100, worse than 73% of steel grades); weldability not recommended (12/100); formability fair (45/100).
Common Calculations5
Values are nominal handbook figures for design screening. Confirm any required mill or lot documentation when quoting.
Working with SUJ1 Annealed
Is SUJ1 easy to machine?
Machine only in the spheroidize-annealed state (~190 HB) with coated carbide and rigid setups; after hardening use CBN hard turning or grinding.
Can SUJ1 be welded?
Effectively unweldable at ~1 %C — if unavoidable, preheat 300–400 °C, use low-hydrogen filler and re-anneal immediately; expect martensite cracking.
Can SUJ1 be formed, bent or molded?
Cold heading/ring rolling only from fully spheroidized stock; hot forging 1050–1100 °C with slow cool then spheroidize anneal (860 °C isothermal at ~720 °C).
What surface finishes work on SUJ1?
Grind, lap and superfinish for raceways; protect with oil, black oxide, manganese phosphate or hard chrome — no anodizing and negligible bare-metal corrosion resistance.
SUJ1 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 |
| Si | 0.15 – 0.35 | 0.25 |
| Mn | ≤ 0.5 | 0.35 |
| Pimpurity limit | ≤ 0.03 | 0.01 |
| Simpurity limit | ≤ 0.03 | 0.01 |
| Crlower than SUJ2 (1.30–1.60), hence lower hardenability | 0.9 – 1.2 | 1.05 |
| Moresidual | ≤ 0.08 | 0.02 |
| Niresidual | ≤ 0.25 | 0.08 |
| Curesidual | ≤ 0.25 | 0.08 |
| Ooxygen limit for cleanliness (vacuum-degassed bearing steel practice) | ≤ 0 | 8×10⁻⁴ |
| Fe | balance | — |
SUJ1 Annealed — frequently asked
What is SUJ1 Annealed used for?
SUJ1 Annealed is typically used for small ball and roller bearings, bearing balls and rollers, light-duty rollers and track wheels, needle roller pins, thin-section inner rings and cam follower rollers. In short: lightest-duty SUJ grade; easiest-forming bearing steel; 50100 equivalent.
What is the yield strength of SUJ1 Annealed?
SUJ1 Annealed has a typical yield strength of 400 MPa (58 ksi) and a tensile strength of 660 MPa (95.7 ksi) — weaker than 60% of steel grades. Strength varies by condition: see the 9 listed tempers.
Is SUJ1 Annealed easy to machine?
Not especially — machinability is rated fair (42/100, worse than 73% of steel grades). Machine only in the spheroidize-annealed state (~190 HB) with coated carbide and rigid setups; after hardening use CBN hard turning or grinding.
Can SUJ1 Annealed be welded?
Not readily — weldability is rated not recommended (12/100). Effectively unweldable at ~1 %C — if unavoidable, preheat 300–400 °C, use low-hydrogen filler and re-anneal immediately; expect martensite cracking.
What surface finishes work on SUJ1 Annealed?
Grind, lap and superfinish for raceways; protect with oil, black oxide, manganese phosphate or hard chrome — no anodizing and negligible bare-metal corrosion resistance.
Can SUJ1 Annealed be formed, bent or molded?
Cold heading/ring rolling only from fully spheroidized stock; hot forging 1050–1100 °C with slow cool then spheroidize anneal (860 °C isothermal at ~720 °C).
What is the maximum service temperature of SUJ1 Annealed?
SUJ1 Annealed 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 SUJ1 Annealed and SUJ1-MQ?
Annealed is the default condition — standard stock condition for machining, cold forming and turning of rings/rollers before hardening. MQ: bainitic or martempered route chosen to cut quench distortion and raise toughness/compressive residual stress in thin rings. Yield strength is 400 MPa in Annealed versus 1,700 MPa in MQ.
Sources
- JIS G 4805 High-carbon chromium bearing steels — JSA (2019)
- ASTM A295/A295M High-Carbon Anti-Friction Bearing Steel (incl. 50100) — ASTM (2014)
- GB/T 18254 (GCr9 / GCr15) — SAC (2016)
- ASM Handbook Vol.1: Properties and Selection — Irons, Steels, and High-Performance Alloys (bearing steels) — ASM International (1990)
- Machinery's Handbook (machinability ratings, heat treatment of bearing steels) — 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.