Steel 8650 · hardness band
Steel 8650 Q&T 425C
Properties of the Q&T 425C condition, compared with the other 8650 tempers.
Higher-strength/wear condition for pins, cams and light tooling where toughness demand is moderate.
What is 8650 Q&T 425C?
8650 Q&T 425C is 8650 heat treated to Q&T 425C — higher-strength/wear condition for pins, cams and light tooling where toughness demand is moderate. 8650 Q&T 425C has a yield strength of 1,325 MPa (192 ksi) and a tensile strength of 1,450 MPa (210 ksi) — stronger than 95% of steel grades. Elongation at break is 12% and the elastic modulus is 205 GPa (29.7 Msi). 8650 Q&T 425C 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). HR is the default condition FabDigit quotes; Q&T 425C is available on request or by drawing note.
Advantages
- High strength — 1,325 MPa (192 ksi), better than 95% of steel grades
- Polishes to a fine finish — 65/100, better than 78% of steel grades
Limitations
- Difficult to machine — 22/100, worse than 96% of steel grades
- Limited ductility — 12%, worse than 84% of steel grades
- Low fracture toughness — 60 MPa·√m (54.6 ksi·√in), worse than 79% of steel grades
8650 Q&T 425C properties
Typical room-temperature values for 8650 Q&T 425C — 12 properties are specific to this condition; the rest are grade-level values shared by every 8650 temper. Each bar shows where the value sits among the steel grades in FabDigit's library — further right is higher.
Physical3
8650 Q&T 425C 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).
Mechanical15
8650 Q&T 425C has a yield strength of 1,325 MPa (192 ksi) and a tensile strength of 1,450 MPa (210 ksi) — stronger than 95% of steel grades. Elongation at break is 12% and the elastic modulus is 205 GPa (29.7 Msi).
Thermal6
8650 Q&T 425C is rated for continuous service to 400°C (752 °F). It conducts heat at 45 W/m·K (26 BTU/hr·ft·°F), better than 66% of steel grades. Thermal expansion is 12.3 µm/m·K (6.83 µin/in·°F).
Electrical3
8650 Q&T 425C conducts electricity at 7.8 % IACS, worse than 58% of steel grades.
Chemical & Environmental3
Corrosion resistance is not recommended (12/100), worse than 53% of steel grades.
Sustainability4
Producing a kilogram of 8650 Q&T 425C takes about 29 MJ of energy and emits 2.2 kg of CO₂ — less than 53% of steel grades. Typical recycled content is 30%.
Manufacturability7
8650 Q&T 425C's machinability is poor (22/100, worse than 96% of steel grades); weldability poor (28/100); formability poor (30/100).
Values are nominal handbook figures for design screening. Certified mill or lot data ships with every FabDigit order on request.
Other 8650 tempers and conditions
8650 is also supplied in 10 other conditions. The full side-by-side table is on the 8650 overview.
- HRDefaultCheapest stock form for parts that will be fully heat treated after rough machining.550 MPa yield · 24 HRC
- Q&T 205CMaximum-hardness/strength condition for wear parts; low ductility and notch sensitivity, avoid impact loading.1,675 MPa yield · 54 HRC
- Q&T 425CHigher-strength/wear condition for pins, cams and light tooling where toughness demand is moderate.1,325 MPa yield · 45 HRC
- Q&TGeneral-purpose high-strength condition (~36-40 HRC) balancing strength, fatigue life and toughness.1,055 MPa yield · 39 HRC
- Q&T 34-38 HRCCommon ordering band for gears, sprockets and pins needing higher wear resistance while still machinable.985 MPa yield · 36 HRC
- Q&T 28-32 HRCTough, readily machinable hardness band for shafts and large sections where impact matters more than wear.830 MPa yield · 30 HRC
- CDCold-drawn (usually annealed-then-drawn) bar giving straight, size-accurate stock with higher yield and better finish than hot rolled.790 MPa yield · 28 HRC
- NormalizedUniform fine-grain structure with high as-cooled strength; use to refine forgings before final hardening.690 MPa yield · 32 HRC
- AnnealedSoftest condition; choose for heavy machining, cold forming or before re-hardening.386 MPa yield · 212 HB
Working with 8650 Q&T 425C
Is 8650 easy to machine?
Best machined annealed or ≤32 HRC with rigid setups, carbide tooling and generous coolant; above ~40 HRC switch to CBN/ceramic or grinding.
Can 8650 be welded?
Poor weldability at 0.50 %C — preheat 260-370 °C, use low-hydrogen consumables and temper immediately after welding; avoid welding in the hardened condition.
Can 8650 be formed, bent or molded?
Cold forming only in the annealed/spheroidized state with generous bend radii; hot forge 1050-1200 °C then normalize before hardening.
What surface finishes work on 8650?
Not anodizable; protect with black oxide, phosphate, zinc or hard-chrome plating (bake to relieve hydrogen above 40 HRC), or take a high polish for die/tool surfaces.
8650 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 |
|---|---|---|
| C8650 = 0.50 %C nominal | 0.48 – 0.53 | 0.5 |
| 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 | 0.02 |
| Smax; 8650H/86L50 variants differ | ≤ 0.04 | 0.03 |
| Fe | balance | — |
8650 Q&T 425C — frequently asked
What is 8650 Q&T 425C used for?
8650 Q&T 425C is typically used for shafts, gears and axles. In short: workhorse Ni-Cr-Mo bar.
What is the yield strength of 8650 Q&T 425C?
8650 Q&T 425C has a typical yield strength of 1,325 MPa (192 ksi) and a tensile strength of 1,450 MPa (210 ksi) — stronger than 95% of steel grades. Strength varies by condition: see the 11 listed tempers.
Is 8650 Q&T 425C easy to machine?
Not especially — machinability is rated poor (22/100, worse than 96% of steel grades). Best machined annealed or ≤32 HRC with rigid setups, carbide tooling and generous coolant; above ~40 HRC switch to CBN/ceramic or grinding.
Can 8650 Q&T 425C be welded?
Not readily — weldability is rated poor (28/100). Poor weldability at 0.50 %C — preheat 260-370 °C, use low-hydrogen consumables and temper immediately after welding; avoid welding in the hardened condition.
What surface finishes work on 8650 Q&T 425C?
Not anodizable; protect with black oxide, phosphate, zinc or hard-chrome plating (bake to relieve hydrogen above 40 HRC), or take a high polish for die/tool surfaces.
Can 8650 Q&T 425C be formed, bent or molded?
Cold forming only in the annealed/spheroidized state with generous bend radii; hot forge 1050-1200 °C then normalize before hardening.
What is the maximum service temperature of 8650 Q&T 425C?
8650 Q&T 425C 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 8650-HR and 8650-CD?
HR is the default condition — cheapest stock form for parts that will be fully heat treated after rough machining. CD: cold-drawn (usually annealed-then-drawn) bar giving straight, size-accurate stock with higher yield and better finish than hot rolled. Yield strength is 550 MPa in HR versus 790 MPa in CD.
Can FabDigit make parts in 8650 Q&T 425C?
Yes — 8650 Q&T 425C 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, General Requirements — ASTM (2020)
- 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)
- Atlas of Stress-Strain Curves / Heat Treater's Guide: Standard Steels — ASM International (1995)
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.