Steel 4626 QT-28-32HRC
Hardness band
AISI/SAE 4626 · UNS G46260
Use oil quenching with a high-temperature temper to 28–32 HRC when impact toughness leads, as on large-section pins, connecting rods and shafts, accepting 830 MPa yield instead of peak strength.
Values for the QT-28-32HRC condition
Other 4626 tempers and conditions
4626 is listed in 9 conditions; see the grade overview at 4626.
- A
- HR
- N
- CD
- QT-28-32HRC
- CARB
- AQ
- QT-32-36HRC
- QT-38-42HRC
Compare all 9 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
ADefault Solution annealed | Choose the fully annealed, spheroidized state at 156 HB as the softest condition for machining and cold forming, and the usual aerospace bar stock; strength comes only from later quench and temper. | 350 | 540 | 27 | 156 HB | — |
Hot rolled | Pick the lowest-cost as-rolled bar for blanks that will be forged and then fully heat treated; at 187 HB the surface and hardness are uneven, so leave generous machining stock. | 400 | 640 | 22 | 187 HB | 7.8 % IACS |
Normalized | Normalize at 870–900 °C and air cool to refine forging structure and even out properties, either as a pre-treatment before quench and temper or for moderate 420 MPa yield service. | 420 | 660 | 23 | 192 HB | 7.8 % IACS |
Cold drawn | Pick cold-drawn bar for close dimensional tolerance, good surface and 580 MPa yield on pin and shaft parts needing little machining; cold work cuts elongation to 15 % and formability. | 580 | 680 | 15 | 15 HRC | 7.8 % IACS |
QT-28-32HRCThis page oil quenched and high-temperature tempered | Use oil quenching with a high-temperature temper to 28–32 HRC when impact toughness leads, as on large-section pins, connecting rods and shafts, accepting 830 MPa yield instead of peak strength. | 830 | 960 | 18 | 30 HRC | — |
Carburized, quenched and tempered | Specify carburizing, quenching and tempering for gears, bushings and pins that need a 60 HRC wear- and contact-fatigue-resistant case over a tough core; welding is effectively excluded. | 950 | 1,150 | 12 | 60 HRC | — |
Aircraft Quality | Order vacuum-degassed, low-sulphur, ultrasonically inspected bar for fatigue- and fracture-critical parts such as landing-gear pins; mechanical properties follow the quench-and-temper hardness chosen. | 950 | 1,100 | 18 | 35 HRC | 7.5 % IACS |
oil quenched and tempered | Use this balanced oil-quenched and tempered state, 32–36 HRC and 970 MPa yield, as the default delivery hardness for medium-duty landing-gear pins and shafts, with 16 % elongation retained. | 970 | 1,100 | 16 | 34 HRC | — |
oil quenched and low-temperature tempered | Pick the oil quench plus low-temperature temper to 38–42 HRC for highly stressed pins and wear-resistant journals; toughness and hydrogen-embrittlement margin fall, so plate with care. | 1,180 | 1,300 | 13 | 40 HRC | — |
What is 4626 QT-28-32HRC?
4626 QT-28-32HRC is 4626 heat treated to QT-28-32HRC — use oil quenching with a high-temperature temper to 28–32 HRC when impact toughness leads, as on large-section pins, connecting rods and shafts, accepting 830 MPa yield instead of peak strength. 4626 QT-28-32HRC has a yield strength of 830 MPa (120 ksi) and a tensile strength of 960 MPa (139 ksi) — stronger than 87% of steel grades. Elongation at break is 18% and the elastic modulus is 205 GPa (29.7 Msi). 4626 QT-28-32HRC has a density of 7.85 g/cm³ (0.284 lb/in³), heavier than 56% of steel grades. It melts at 1,425°C (2,597 °F). A is the default condition FabDigit quotes; QT-28-32HRC is available on request or by drawing note.
Advantages
- High strength — 830 MPa (120 ksi), better than 87% of steel grades
- Polishes to a fine finish — 65/100, better than 78% of steel grades
4626 QT-28-32HRC properties
Typical room-temperature values for 4626 QT-28-32HRC; 14 are specific to this condition. Other listed values are 4626 reference data and may not represent this condition. Bars are the position among steel grades.
Physical3
4626 QT-28-32HRC has a density of 7.85 g/cm³ (0.284 lb/in³), heavier than 56% of steel grades. It melts at 1,425°C (2,597 °F).
Mechanical14
4626 QT-28-32HRC has a yield strength of 830 MPa (120 ksi) and a tensile strength of 960 MPa (139 ksi) — stronger than 87% of steel grades. Elongation at break is 18% and the elastic modulus is 205 GPa (29.7 Msi).
Thermal6
4626 QT-28-32HRC is rated for continuous service to 425°C (797 °F). It conducts heat at 44 W/m·K (25.4 BTU/hr·ft·°F), better than 57% of steel grades. Thermal expansion is 11.9 µm/m·K (6.61 µin/in·°F).
Electrical3
4626 QT-28-32HRC conducts electricity at 7.8 % IACS, worse than 57% of steel grades.
Chemical & Environmental3
Corrosion resistance is not recommended (12/100), worse than 53% of steel grades.
Sustainability4
Producing a kilogram of 4626 QT-28-32HRC takes about 32 MJ of energy and emits 2.3 kg of CO₂ — more than 70% of steel grades. Typical recycled content is 25%.
Manufacturability7
4626 QT-28-32HRC's machinability is good (60/100, better than 83% of steel grades); weldability fair (35/100); formability fair (50/100).
Values are nominal handbook figures for design screening. Confirm any required mill or lot documentation when quoting.
Working with 4626 QT-28-32HRC
Is 4626 easy to machine?
Turn and mill annealed or normalized bar with carbide tooling at roughly 60–65 % of the 1212 rate. Above 35 HRC after quench and temper, reduce cutting speed and use coated inserts; complete finishing operations before heat treatment where possible.
Can 4626 be welded?
Carbon equivalent is high, so weld with 150–260 °C preheat and low-hydrogen consumables, then temper immediately after welding. Carburized parts and high-hardness quenched-and-tempered parts are normally not welded.
Can 4626 be formed, bent or molded?
Warm or hot forge annealed material at 1050–1200 °C; cold formability is limited. Normalize after forging to refine the structure before quench and temper.
What surface finishes work on 4626?
Cadmium, zinc-nickel or hard chrome plating, or phosphate plus paint, are the usual corrosion protection. High-strength parts must be baked at 190 °C for several hours after plating to remove hydrogen; the steel polishes to a mirror finish but must be protected immediately.
4626 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 |
|---|---|---|
| CSAE J404 / UNS G46260 | 0.24 – 0.29 | 0.27 |
| Mn | 0.45 – 0.65 | 0.55 |
| Si | 0.15 – 0.35 | 0.25 |
| Ni | 0.7 – 1 | 0.85 |
| Mo | 0.15 – 0.25 | 0.2 |
| Paerospace quality often limited to 0.025 max | ≤ 0.04 | — |
| Saerospace quality often limited to 0.025 max | ≤ 0.04 | — |
| Fe | balance | — |
4626 QT-28-32HRC — frequently asked
What is 4626 QT-28-32HRC used for?
4626 QT-28-32HRC is typically used for landing gear pins, aircraft bolts and high-strength shafts. In short: aircraft-quality Ni-Mo steel; low-sulfur, clean steel practice; higher-carbon 46xx grade.
What is the yield strength of 4626 QT-28-32HRC?
4626 QT-28-32HRC has a typical yield strength of 830 MPa (120 ksi) and a tensile strength of 960 MPa (139 ksi) — stronger than 87% of steel grades. Strength varies by condition: see the 9 listed tempers.
Is 4626 QT-28-32HRC easy to machine?
Reasonably — machinability is rated good (60/100, better than 83% of steel grades). Turn and mill annealed or normalized bar with carbide tooling at roughly 60–65 % of the 1212 rate. Above 35 HRC after quench and temper, reduce cutting speed and use coated inserts; complete finishing operations before heat treatment where possible.
Can 4626 QT-28-32HRC be welded?
With care — weldability is rated fair (35/100). Carbon equivalent is high, so weld with 150–260 °C preheat and low-hydrogen consumables, then temper immediately after welding. Carburized parts and high-hardness quenched-and-tempered parts are normally not welded.
What surface finishes work on 4626 QT-28-32HRC?
Cadmium, zinc-nickel or hard chrome plating, or phosphate plus paint, are the usual corrosion protection. High-strength parts must be baked at 190 °C for several hours after plating to remove hydrogen; the steel polishes to a mirror finish but must be protected immediately.
Can 4626 QT-28-32HRC be formed, bent or molded?
Warm or hot forge annealed material at 1050–1200 °C; cold formability is limited. Normalize after forging to refine the structure before quench and temper.
What is the maximum service temperature of 4626 QT-28-32HRC?
4626 QT-28-32HRC is rated for continuous use to about 425°C (797 °F). Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
What is the difference between 4626-A and 4626 CARB?
A is the default condition — choose the fully annealed, spheroidized state at 156 HB as the softest condition for machining and cold forming, and the usual aerospace bar stock; strength comes only from later quench and temper. CARB: specify carburizing, quenching and tempering for gears, bushings and pins that need a 60 HRC wear- and contact-fatigue-resistant case over a tough core; welding is effectively excluded. Yield strength is 350 MPa in A versus 950 MPa in CARB.
Sources
- SAE J404 — Chemical Compositions of SAE Alloy Steels — SAE International (2021)
- SAE J1268 — Hardenability Bands for Alloy H Steels (4626H) — SAE International (2018)
- ASTM A29/A29M — Steel Bars, Carbon and Alloy, Hot-Wrought — 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)
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.