Steel 8660 · heat-treated state
Steel 8660 Normalized
Properties of the Normalized condition, compared with the other 8660 tempers.
Use to homogenize forgings and refine grain before hardening; gives high strength but low ductility for this carbon level.
What is 8660 Normalized?
8660 Normalized is 8660 heat treated to Normalized — use to homogenize forgings and refine grain before hardening; gives high strength but low ductility for this carbon level. 8660 Normalized has a yield strength of 690 MPa (100 ksi) and a tensile strength of 1,105 MPa (160 ksi) — stronger than 80% of steel grades. Elongation at break is 14% and the elastic modulus is 205 GPa (29.7 Msi). 8660 Normalized has a density of 7.85 g/cm³ (0.284 lb/in³), heavier than 56% of steel grades. It melts at 1,415°C (2,579 °F). HR is the default condition FabDigit quotes; Normalized is available on request or by drawing note.
Advantages
- High strength — 690 MPa (100 ksi), better than 80% of steel grades
- Polishes to a fine finish — 65/100, better than 78% of steel grades
Limitations
- Difficult to weld — 20/100, worse than 84% of steel grades
- Limited ductility — 14%, worse than 75% of steel grades
8660 Normalized properties
Typical room-temperature values for 8660 Normalized — 9 properties are specific to this condition; the rest are grade-level values shared by every 8660 temper. Each bar shows where the value sits among the steel grades in FabDigit's library — further right is higher.
Physical3
8660 Normalized has a density of 7.85 g/cm³ (0.284 lb/in³), heavier than 56% of steel grades. It melts at 1,415°C (2,579 °F).
Mechanical13
8660 Normalized has a yield strength of 690 MPa (100 ksi) and a tensile strength of 1,105 MPa (160 ksi) — stronger than 80% of steel grades. Elongation at break is 14% and the elastic modulus is 205 GPa (29.7 Msi).
Thermal6
8660 Normalized is rated for continuous service to 400°C (752 °F). It conducts heat at 44 W/m·K (25.4 BTU/hr·ft·°F), better than 57% of steel grades. Thermal expansion is 11.7 µm/m·K (6.5 µin/in·°F).
Electrical3
8660 Normalized conducts electricity at 7.2 % IACS, worse than 71% of steel grades.
Chemical & Environmental3
Corrosion resistance is not recommended (11/100), worse than 73% of steel grades.
Sustainability4
Producing a kilogram of 8660 Normalized takes about 30 MJ of energy and emits 2.2 kg of CO₂ — more than 55% of steel grades. Typical recycled content is 30%.
Manufacturability6
8660 Normalized's machinability is fair (42/100, worse than 72% of steel grades); weldability poor (20/100); formability poor (25/100).
Values are nominal handbook figures for design screening. Certified mill or lot data ships with every FabDigit order on request.
Other 8660 tempers and conditions
8660 is also supplied in 9 other conditions. The full side-by-side table is on the 8660 overview.
- HRDefaultStandard stock condition for bar and plate that will be machined and then heat treated by the user.585 MPa yield · 29 HRC
- Q&T 48-52 HRCMaximum practical hardness/wear level for this grade; use only where impact and notch sensitivity are controlled.1,500 MPa yield · 50 HRC
- Q&T 40-45 HRCHigh-strength wear-resistant level for cams, sprockets and tool bodies; ductility drops noticeably.1,280 MPa yield · 42 HRC
- Q&TGeneral-purpose hardened-and-tempered condition for shafts and machine parts needing high strength with usable toughness.1,080 MPa yield · 38 HRC
- Q&T 33-37 HRCBalanced strength/toughness level widely specified for gears and highly loaded shafting.1,000 MPa yield · 35 HRC
- Q&T 28-32 HRCTough, machinable strength level for larger shafts and torsion members where impact matters.855 MPa yield · 30 HRC
- CDChoose for close size tolerance and straight bright bar where no further heat treatment is planned.790 MPa yield · 28 HRC
- NormalizedUse to homogenize forgings and refine grain before hardening; gives high strength but low ductility for this carbon level.690 MPa yield · 34 HRC
- AnnealedPick when maximum machinability or cold-forming ability is needed before hardening.460 MPa yield · 230 HB
Working with 8660 Normalized
Is 8660 easy to machine?
Machine in the annealed or ≤32 HRC condition with rigid setups, carbide tooling and generous coolant; above ~40 HRC switch to grinding or CBN turning.
Can 8660 be welded?
Poor weldability at 0.60 % C — avoid if possible; if required use low-hydrogen consumables, 250–350 °C preheat, interpass control and immediate post-weld temper.
Can 8660 be formed, bent or molded?
Cold forming is limited to mild bends in the spheroidize-annealed state; hot forge at 1100–1200 °C, finish above 900 °C and slow cool or normalize afterwards.
What surface finishes work on 8660?
Not anodizable; protect with phosphate + oil, black oxide, zinc or hard chrome, and stress-relieve/bake after plating to avoid hydrogen embrittlement at high hardness.
8660 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 | 0.56 – 0.64 | 0.6 |
| Mn | 0.75 – 1 | 0.88 |
| Si | 0.15 – 0.35 | 0.25 |
| Ni | 0.4 – 0.7 | 0.55 |
| Cr | 0.4 – 0.6 | 0.5 |
| Mo | 0.15 – 0.25 | 0.2 |
| P | ≤ 0.04 | — |
| S | ≤ 0.04 | — |
| Fe | balance | — |
8660 Normalized — frequently asked
What is 8660 Normalized used for?
8660 Normalized is typically used for drive shafts, pinion shafts, gears and gear blanks, torsion bars and spring anchors, wear plates and liners and forged sprockets and couplings. In short: workhorse Ni-Cr-Mo bar.
What is the yield strength of 8660 Normalized?
8660 Normalized has a typical yield strength of 690 MPa (100 ksi) and a tensile strength of 1,105 MPa (160 ksi) — stronger than 80% of steel grades. Strength varies by condition: see the 10 listed tempers.
Is 8660 Normalized easy to machine?
Not especially — machinability is rated fair (42/100, worse than 72% of steel grades). Machine in the annealed or ≤32 HRC condition with rigid setups, carbide tooling and generous coolant; above ~40 HRC switch to grinding or CBN turning.
Can 8660 Normalized be welded?
Not readily — weldability is rated poor (20/100). Poor weldability at 0.60 % C — avoid if possible; if required use low-hydrogen consumables, 250–350 °C preheat, interpass control and immediate post-weld temper.
What surface finishes work on 8660 Normalized?
Not anodizable; protect with phosphate + oil, black oxide, zinc or hard chrome, and stress-relieve/bake after plating to avoid hydrogen embrittlement at high hardness.
Can 8660 Normalized be formed, bent or molded?
Cold forming is limited to mild bends in the spheroidize-annealed state; hot forge at 1100–1200 °C, finish above 900 °C and slow cool or normalize afterwards.
What is the maximum service temperature of 8660 Normalized?
8660 Normalized is rated for continuous use to about 400°C (752 °F). Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
What is the difference between 8660-HR and 8660-CR?
HR is the default condition — standard stock condition for bar and plate that will be machined and then heat treated by the user. CR: strip/sheet form for blanking and spring-type parts that are subsequently hardened and tempered. Yield strength is 585 MPa in HR versus 800 MPa in CR.
Can FabDigit make parts in 8660 Normalized?
Yes — 8660 Normalized 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
- SAE J404 — Chemical Compositions of SAE Alloy Steels — SAE International (2021)
- ASTM A29/A29M — Steel Bars, Carbon and Alloy, Hot-Wrought — ASTM (2020)
- SAE J1268 — Hardenability Bands for Carbon and Alloy H Steels — SAE International (2019)
- ASM Handbook Vol.1 — Properties and Selection: Irons, Steels and High-Performance Alloys — ASM International (1990)
- ASM Handbook Vol.4 — Heat Treating — ASM International (1991)
- ASM Handbook Vol.16 — Machining — ASM International (1989)
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.