Steel SCM822
JIS SCM822
SCM822 is a nickel-free chromium-molybdenum case-hardening steel from the JIS low-alloy carburizing family, relying on Cr and Mo for hardenability instead of nickel.
Reference datasheet — SCM822 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 A condition
SCM822 tempers and conditions
SCM822 is supplied in 8 conditions, soft to hard. A 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 |
|---|---|---|---|---|---|---|
Spheroidize annealed | Choose for cold-forged/upset gear blanks and CVJ parts where maximum cold formability is needed before carburizing. | 400 | 640 | 26 | 175 HB | 8 % IACS |
ADefault Solution annealed | Standard stocked condition: soft, uniform structure for turning, hobbing and shaping before carburizing. | 460 | 720 | 21 | 14 HRC | 8 % IACS |
Hot rolled | Cheapest mill condition for parts that will be fully heat treated anyway; hardness scatter and mill scale must be turned off. | 560 | 850 | 16 | 24 HRC | 8 % IACS |
Normalized | Used to refine and homogenise forged blanks and reduce carburizing distortion; harder than annealed. | 560 | 830 | 18 | 23 HRC | 8 % IACS |
Cold drawn | Bright, close-tolerance small-diameter bar for automatic-lathe pinion and shaft blanks. | 700 | 830 | 11 | 24 HRC | 8 % IACS |
Quenched and tempered | Direct-hardened condition used for shafts and non-carburized parts, and the JIS acceptance condition for core strength (≥1030 MPa). | 930 | 1,130 | 14 | 33 HRC | — |
Carburized and hardened | The service condition for gears: hard wear-resistant case with a tough 35–45 HRC core; properties below are case values, tensile data refer to the core. | 1,000 | 1,250 | 11 | 60 HRC | — |
Carburized, hardened and shot peened | Pick for maximum tooth-root bending fatigue on highly loaded transmission gears; peening adds compressive residual stress in the case. | 1,050 | 1,230 | 11 | 61 HRC | 7 % IACS |
What is SCM822?
SCM822 is a nickel-free chromium-molybdenum case-hardening steel from the JIS low-alloy carburizing family, relying on Cr and Mo for hardenability instead of nickel. Engineers select it for heavily loaded automotive and industrial gearing, where a 58–62 HRC case runs on a tough core; it is supplied as hot-rolled, annealed, spheroidize-annealed, normalized, cold-drawn and quenched-and-tempered bar and forging stock. In the default condition it gives 460 MPa yield, 720 MPa tensile, 21 % elongation and about 200 HB, with a machinability score of 55. It has no inherent corrosion resistance and is not intended for welding; SNCM420 is the usual step up when higher core toughness is needed. SCM822 has a density of 7.85 g/cm³ (0.284 lb/in³), heavier than 56% of steel grades. It melts at 1,420°C (2,588 °F). SCM822 has a yield strength of 460 MPa (66.7 ksi) and a tensile strength of 720 MPa (104 ksi) — stronger than 55% of steel grades. Elongation at break is 21% and the elastic modulus is 206 GPa (29.9 Msi).
What is SCM822 used for?
- Transmission gears
- Differential gears
- Ring and pinion sets
- Gearbox shafts and pinion shafts
- Constant-velocity joint blanks
- Splined drive couplings
- Industrial reducer gearing
SCM822 properties
Typical room-temperature values for SCM822-A; bars are the position among steel grades.
Physical3
SCM822 has a density of 7.85 g/cm³ (0.284 lb/in³), heavier than 56% of steel grades. It melts at 1,420°C (2,588 °F).
Mechanical17
SCM822 has a yield strength of 460 MPa (66.7 ksi) and a tensile strength of 720 MPa (104 ksi) — stronger than 55% of steel grades. Elongation at break is 21% and the elastic modulus is 206 GPa (29.9 Msi).
Thermal6
SCM822 is rated for continuous service to 350°C (662 °F). It conducts heat at 42 W/m·K (24.3 BTU/hr·ft·°F), worse than 56% of steel grades. Thermal expansion is 12.3 µm/m·K (6.83 µin/in·°F).
Electrical3
SCM822 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 SCM822 takes about 30 MJ of energy and emits 2.2 kg of CO₂ — more than 56% of steel grades. Typical recycled content is 30%.
Manufacturability7
SCM822's machinability is good (55/100, better than 62% of steel grades); weldability poor (30/100); formability fair (45/100).
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. SCM822 is highlighted; hover a dot for its name, or open the interactive family chart.
Working with SCM822
Is SCM822 easy to machine?
Machine in the annealed/normalized state with coated carbide at moderate speeds; leave 0.1–0.3 mm stock for post-carburizing grinding since the 58–62 HRC case is grind-only.
Can SCM822 be welded?
Not intended for welding — high Cr+Mo hardenability gives brittle martensite; if unavoidable, preheat 250–350 °C, use low-hydrogen consumables and temper immediately, and never weld carburized surfaces.
Can SCM822 be formed, bent or molded?
Hot forge 1150–900 °C then normalize or anneal; spheroidize-annealed stock cold-forges well for gear and CVJ blanks.
SCM822 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 |
|---|---|---|
| CJIS G 4053 | 0.2 – 0.25 | 0.22 |
| Si | 0.15 – 0.35 | 0.25 |
| Mn | 0.6 – 0.9 | 0.75 |
| P | ≤ 0.03 | |
| S | ≤ 0.03 | |
| Cr | 0.9 – 1.2 | 1.05 |
| Mohigher Mo than SCM420 — main distinguishing element | 0.35 – 0.45 | 0.4 |
| Niresidual | ≤ 0.25 | |
| Curesidual | ≤ 0.3 | |
| Fe | balance |
What surface finishes work on SCM822?
Grind or hard-turn after case hardening, then shot peen for fatigue; protect bare surfaces with oil, phosphate, black oxide or Zn/Mn coating — the steel has no inherent 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 SCM822 cost?
SCM822 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.
SCM822 — frequently asked
What is SCM822 used for?
SCM822 is typically used for transmission gears, differential gears, ring and pinion sets, gearbox shafts and pinion shafts, constant-velocity joint blanks and splined drive couplings. In short: nickel-free carburizing steel; high Cr-Mo hardenability; gear-grade case toughness.
What is the yield strength of SCM822?
SCM822 has a typical yield strength of 460 MPa (66.7 ksi) and a tensile strength of 720 MPa (104 ksi) — stronger than 55% of steel grades. Strength varies by condition: see the 8 listed tempers.
Is SCM822 easy to machine?
Reasonably — machinability is rated good (55/100, better than 62% of steel grades). Machine in the annealed/normalized state with coated carbide at moderate speeds; leave 0.1–0.3 mm stock for post-carburizing grinding since the 58–62 HRC case is grind-only.
Can SCM822 be welded?
Not readily — weldability is rated poor (30/100). Not intended for welding — high Cr+Mo hardenability gives brittle martensite; if unavoidable, preheat 250–350 °C, use low-hydrogen consumables and temper immediately, and never weld carburized surfaces.
What surface finishes work on SCM822?
Grind or hard-turn after case hardening, then shot peen for fatigue; protect bare surfaces with oil, phosphate, black oxide or Zn/Mn coating — the steel has no inherent corrosion resistance.
Can SCM822 be formed, bent or molded?
Hot forge 1150–900 °C then normalize or anneal; spheroidize-annealed stock cold-forges well for gear and CVJ blanks.
What is the maximum service temperature of SCM822?
SCM822 is rated for continuous use to about 350°C (662 °F). Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
What is the difference between SCM822-A and SCM822-CH?
A is the default condition — standard stocked condition: soft, uniform structure for turning, hobbing and shaping before carburizing. CH: the service condition for gears: hard wear-resistant case with a tough 35–45 HRC core; properties below are case values, tensile data refer to the core. Yield strength is 460 MPa in A versus 1,000 MPa in CH.
How much does SCM822 cost?
SCM822 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 4053 — Low-alloyed steels for machine structural use — Japanese Standards Association (2016)
- ASM Handbook Vol. 1 — Properties and Selection: Irons, Steels, and High-Performance Alloys — ASM International (1990)
- ASM Handbook Vol. 4A/4D — Steel Heat Treating / Carburizing — ASM International (2014)
- Machinery's Handbook, 31st ed. (machinability and heat-treat data) — Industrial Press (2020)
- GB/T 3077 — Alloy structural steels (comparison of 22CrMo-type grades) — SAC (2015)
- (Mysteel / SMM / 1688 ) — Mysteel, SMM (2026)
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.