Steel 4817 QT-DH
Heat-treated state
AISI/SAE 4817 · UNS G48170
QT-DH = q&T
For through-hardened parts (fasteners, shafts) where a carburized case is not wanted but very high core toughness is.
Values for the QT-DH condition
Other 4817 tempers and conditions
4817 is listed in 6 conditions; see the grade overview at 4817.
Compare all 6 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
Hot rolled | Cheapest mill condition for rough forging or machining stock that will be annealed before carburizing. | 440 | 720 | 22 | 15 HRC | 6.9 % IACS |
ADefault Solution annealed | Standard stocking and machining condition prior to carburizing; softest, most stable structure. | 450 | 690 | 24 | 195 HB | — |
Normalized | Use to refine forging grain and give a uniform core structure before carburizing; slightly stronger and tougher than annealed. | 490 | 760 | 23 | 17 HRC | 6.9 % IACS |
Cold drawn | Pick for close-tolerance small-diameter bar and better surface finish where core strength before case hardening is helpful. | 660 | 790 | 13 | 20 HRC | 6.9 % IACS |
Carburized & hardened | The intended service condition: hard wear-resistant case on a tough high-nickel core for gears, pinions and races. | 950 | 1,200 | 12 | 60 HRC | — |
QT-DHThis page Q&T | For through-hardened parts (fasteners, shafts) where a carburized case is not wanted but very high core toughness is. | 1,000 | 1,240 | 13 | 39 HRC | — |
What is 4817 QT-DH?
4817 QT-DH is 4817 heat treated to QT-DH — for through-hardened parts (fasteners, shafts) where a carburized case is not wanted but very high core toughness is. 4817 QT-DH has a yield strength of 1,000 MPa (145 ksi) and a tensile strength of 1,240 MPa (180 ksi) — stronger than 92% of steel grades. Elongation at break is 13% and the elastic modulus is 205 GPa (29.7 Msi). 4817 QT-DH has a density of 7.83 g/cm³ (0.283 lb/in³), lighter than 80% of steel grades. It melts at 1,420°C (2,588 °F). A is the default condition FabDigit quotes; QT-DH is available on request or by drawing note.
Advantages
- High strength — 1,000 MPa (145 ksi), better than 92% of steel grades
- Polishes to a fine finish — 65/100, better than 78% of steel grades
Limitations
- Limited service temperature — 180°C (356 °F), worse than 98% of steel grades
- Difficult to machine — 25/100, worse than 93% of steel grades
- Difficult to weld — 20/100, worse than 84% of steel grades
- High embodied carbon — 2.5 kg CO₂/kg, worse than 82% of steel grades
- Poor heat conductor — 33 W/m·K (19.1 BTU/hr·ft·°F), worse than 80% of steel grades
4817 QT-DH properties
Typical room-temperature values for 4817 QT-DH; 13 are specific to this condition. Other listed values are 4817 reference data and may not represent this condition. Bars are the position among steel grades.
Physical3
4817 QT-DH has a density of 7.83 g/cm³ (0.283 lb/in³), lighter than 80% of steel grades. It melts at 1,420°C (2,588 °F).
Mechanical14
4817 QT-DH has a yield strength of 1,000 MPa (145 ksi) and a tensile strength of 1,240 MPa (180 ksi) — stronger than 92% of steel grades. Elongation at break is 13% and the elastic modulus is 205 GPa (29.7 Msi).
Thermal6
4817 QT-DH is rated for continuous service to 180°C (356 °F). It conducts heat at 33 W/m·K (19.1 BTU/hr·ft·°F), worse than 80% of steel grades. Thermal expansion is 11.7 µm/m·K (6.5 µin/in·°F).
Electrical2
4817 QT-DH has an electrical resistivity of 2.5×10⁻⁷ Ω·m.
Chemical & Environmental3
Corrosion resistance is not recommended (13/100), better than 66% of steel grades.
Sustainability4
Producing a kilogram of 4817 QT-DH takes about 34 MJ of energy and emits 2.5 kg of CO₂ — more than 82% of steel grades. Typical recycled content is 25%.
Manufacturability7
4817 QT-DH's machinability is poor (25/100, worse than 93% of steel grades); weldability poor (20/100); formability fair (45/100).
Values are nominal handbook figures for design screening. Confirm any required mill or lot documentation when quoting.
Working with 4817 QT-DH
Is 4817 easy to machine?
Machine in the annealed condition with sharp, positive-rake carbide at moderate speeds and generous coolant; the nickel makes chips gummy and work-hardening at the cut edge, so avoid dwelling and finish before carburizing.
Can 4817 be welded?
Weldable only in the un-carburized state with low-hydrogen consumables, 200–300 °C preheat and immediate stress relief; do not weld carburized surfaces — the high-carbon case cracks.
Can 4817 be formed, bent or molded?
Hot forge 1090–1200 °C and finish above 900 °C, then normalize and anneal; cold forming is limited to mild bending or heading of annealed small-diameter bar.
What surface finishes work on 4817?
Grind the case after hardening for size and finish (allow 0.1–0.3 mm stock); protect with oil, phosphate, black oxide or zinc/Cr plating — bake plated parts to avoid hydrogen embrittlement.
4817 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 |
|---|---|---|
| Cone step above 4815, below 4820 | 0.15 – 0.2 | 0.17 |
| Mn | 0.4 – 0.6 | 0.5 |
| Si | 0.15 – 0.35 | 0.25 |
| Ni | 3.25 – 3.75 | 3.5 |
| Mo | 0.2 – 0.3 | 0.25 |
| Pmax, bar/billet | ≤ 0.04 | — |
| Smax, bar/billet | ≤ 0.04 | — |
| Fe | balance | — |
4817 QT-DH — frequently asked
What is 4817 QT-DH used for?
4817 QT-DH is typically used for heavy-duty gears, shafts and aircraft components. In short: high-nickel carburizing steel; tough core in heavy sections; harder to machine than 8620.
What is the yield strength of 4817 QT-DH?
4817 QT-DH has a typical yield strength of 1,000 MPa (145 ksi) and a tensile strength of 1,240 MPa (180 ksi) — stronger than 92% of steel grades. Strength varies by condition: see the 6 listed tempers.
Is 4817 QT-DH easy to machine?
Not especially — machinability is rated poor (25/100, worse than 93% of steel grades). Machine in the annealed condition with sharp, positive-rake carbide at moderate speeds and generous coolant; the nickel makes chips gummy and work-hardening at the cut edge, so avoid dwelling and finish before carburizing.
Can 4817 QT-DH be welded?
Not readily — weldability is rated poor (20/100). Weldable only in the un-carburized state with low-hydrogen consumables, 200–300 °C preheat and immediate stress relief; do not weld carburized surfaces — the high-carbon case cracks.
What surface finishes work on 4817 QT-DH?
Grind the case after hardening for size and finish (allow 0.1–0.3 mm stock); protect with oil, phosphate, black oxide or zinc/Cr plating — bake plated parts to avoid hydrogen embrittlement.
Can 4817 QT-DH be formed, bent or molded?
Hot forge 1090–1200 °C and finish above 900 °C, then normalize and anneal; cold forming is limited to mild bending or heading of annealed small-diameter bar.
What is the maximum service temperature of 4817 QT-DH?
4817 QT-DH is rated for continuous use to about 180°C (356 °F). Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
What is the difference between 4817-A and 4817 QT-DH?
A is the default condition — standard stocking and machining condition prior to carburizing; softest, most stable structure. QT-DH: for through-hardened parts (fasteners, shafts) where a carburized case is not wanted but very high core toughness is. Yield strength is 450 MPa in A versus 1,000 MPa in QT-DH.
Sources
- SAE J404 — Chemical Compositions of SAE Alloy Steels — SAE International (2021)
- SAE J1268 — Hardenability Bands for Carbon and Alloy H Steels — SAE International (2019)
- 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.4A — Steel Heat Treating Fundamentals and Processes (carburizing) — ASM International (2013)
- 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.