Steel 86B45 QT44-48
Heat-treated state
EN 86B45 · UNS G86451
QT44-48 = q&T 44–48 HRC
Maximum through-hardened strength/wear condition; use only where notch sensitivity and hydrogen embrittlement are controlled.
Values for the QT44-48 condition
Other 86B45 tempers and conditions
86B45 is listed in 10 conditions; see the grade overview at 86B45.
Compare all 10 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
Spheroidize Annealed | Use for cold-headed fasteners and cold-extruded blanks where maximum ductility of the carbide structure is needed. | 390 | 620 | 26 | 9 HRC | 8.3 % IACS |
Solution annealed | Pick for maximum machinability and softness before quench-and-temper or cold forming. | 415 | 655 | 22 | 190 HB | 44 W/m·K |
Hot rolled | Cheapest mill condition for stock bar that will be machined then heat treated by the user. | 470 | 760 | 18 | 217 HB | — |
Normalized | Grain refinement and uniform structure ahead of machining or hardening; moderate strength forgings. | 550 | 830 | 17 | 23 HRC | — |
Cold drawn | Choose for tight-tolerance, good-surface bar used as-supplied for shafts and screw-machine parts. | 680 | 790 | 12 | 235 HB | — |
Q&T 28–32 HRC | Tough general-purpose condition for shafts, couplings and machined parts needing good impact resistance. | 840 | 965 | 18 | 30 HRC | — |
QT32-36Default Q&T 32–36 HRC | Standard stocked strength/toughness balance for gear blanks, drive shafts and high-strength fasteners. | 950 | 1,080 | 16 | 34 HRC | — |
Induction hardened | Choose for journal, spline and gear-tooth wear surfaces needing a hard case with a tough tempered core. | 950 | 1,080 | 14 | 57 HRC | 7.3 % IACS |
Q&T 38–42 HRC | Higher-strength condition for heavily loaded shafts, pins and links where some toughness can be traded for strength. | 1,180 | 1,310 | 13 | 40 HRC | — |
QT44-48This page Q&T 44–48 HRC | Maximum through-hardened strength/wear condition; use only where notch sensitivity and hydrogen embrittlement are controlled. | 1,400 | 1,550 | 10 | 46 HRC | — |
What is 86B45 QT44-48?
86B45 QT44-48 is 86B45 heat treated to QT44-48 — maximum through-hardened strength/wear condition; use only where notch sensitivity and hydrogen embrittlement are controlled. 86B45 QT44-48 has a yield strength of 1,400 MPa (203 ksi) and a tensile strength of 1,550 MPa (225 ksi) — stronger than 96% of steel grades. Elongation at break is 10% and the elastic modulus is 205 GPa (29.7 Msi). 86B45 QT44-48 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). QT32-36 is the default condition FabDigit quotes; QT44-48 is available on request or by drawing note.
Advantages
- High strength — 1,400 MPa (203 ksi), better than 96% of steel grades
Limitations
- Difficult to machine — 22/100, worse than 95% of steel grades
- Limited ductility — 10%, worse than 91% of steel grades
- Limited service temperature — 250°C (482 °F), worse than 85% of steel grades
- Low fracture toughness — 52 MPa·√m (47.3 ksi·√in), worse than 84% of steel grades
- Limited formability — 22/100, worse than 76% of steel grades
86B45 QT44-48 properties
Typical room-temperature values for 86B45 QT44-48; 14 are specific to this condition. Other listed values are 86B45 reference data and may not represent this condition. Bars are the position among steel grades.
Physical3
86B45 QT44-48 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).
Mechanical16
86B45 QT44-48 has a yield strength of 1,400 MPa (203 ksi) and a tensile strength of 1,550 MPa (225 ksi) — stronger than 96% of steel grades. Elongation at break is 10% and the elastic modulus is 205 GPa (29.7 Msi).
Thermal6
86B45 QT44-48 is rated for continuous service to 250°C (482 °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
86B45 QT44-48 conducts electricity at 7.8 % IACS, worse than 57% of steel grades.
Chemical & Environmental3
Corrosion resistance is not recommended (11/100), worse than 73% of steel grades.
Sustainability4
Producing a kilogram of 86B45 QT44-48 takes about 28 MJ of energy and emits 2.2 kg of CO₂ — less than 56% of steel grades. Typical recycled content is 30%.
Manufacturability7
86B45 QT44-48's machinability is poor (22/100, worse than 95% of steel grades); weldability poor (28/100); formability poor (22/100).
Values are nominal handbook figures for design screening. Confirm any required mill or lot documentation when quoting.
Working with 86B45 QT44-48
Is 86B45 easy to machine?
Machine in the annealed/normalized state (~190–240 HB) with coated carbide; above 34 HRC use rigid setups, negative-rake carbide or CBN and reduced feeds.
Can 86B45 be welded?
Poor weldability (CE ≈ 0.8–0.9): preheat 250–350 °C, low-hydrogen consumables, and temper immediately after welding to avoid HAZ cracking.
Can 86B45 be formed, bent or molded?
Cold head or form only in the spheroidize-annealed condition; hot forge at 1050–1200 °C and normalize afterwards to restore grain size.
What surface finishes work on 86B45?
No anodizing — protect with zinc/manganese phosphate, black oxide, zinc or Cr plating; bake 190–220 °C for 4 h after plating when above 40 HRC.
86B45 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 86B45 heat analysis | 0.43 – 0.48 | 0.46 |
| 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 |
| Bboron addition for hardenability; requires Ti/Al nitrogen fixation | 5×10⁻⁴ – 0 | 0 |
| P | ≤ 0.04 | — |
| S | ≤ 0.04 | — |
| Fe | balance | — |
86B45 QT44-48 — frequently asked
What is 86B45 QT44-48 used for?
86B45 QT44-48 is typically used for gears, shafts and high-strength bolts. In short: alloy-grade hardenability, less nickel; high-strength shaft and gear steel; poor weldability, coat for corrosion.
What is the yield strength of 86B45 QT44-48?
86B45 QT44-48 has a typical yield strength of 1,400 MPa (203 ksi) and a tensile strength of 1,550 MPa (225 ksi) — stronger than 96% of steel grades. Strength varies by condition: see the 10 listed tempers.
Is 86B45 QT44-48 easy to machine?
Not especially — machinability is rated poor (22/100, worse than 95% of steel grades). Machine in the annealed/normalized state (~190–240 HB) with coated carbide; above 34 HRC use rigid setups, negative-rake carbide or CBN and reduced feeds.
Can 86B45 QT44-48 be welded?
Not readily — weldability is rated poor (28/100). Poor weldability (CE ≈ 0.8–0.9): preheat 250–350 °C, low-hydrogen consumables, and temper immediately after welding to avoid HAZ cracking.
What surface finishes work on 86B45 QT44-48?
No anodizing — protect with zinc/manganese phosphate, black oxide, zinc or Cr plating; bake 190–220 °C for 4 h after plating when above 40 HRC.
Can 86B45 QT44-48 be formed, bent or molded?
Cold head or form only in the spheroidize-annealed condition; hot forge at 1050–1200 °C and normalize afterwards to restore grain size.
What is the maximum service temperature of 86B45 QT44-48?
86B45 QT44-48 is rated for continuous use to about 250°C (482 °F). Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
What is the difference between 86B45 QT32-36 and 86B45-SA?
QT32-36 is the default condition — standard stocked strength/toughness balance for gear blanks, drive shafts and high-strength fasteners. SA: use for cold-headed fasteners and cold-extruded blanks where maximum ductility of the carbide structure is needed. Yield strength is 950 MPa in QT32-36 versus 390 MPa in SA.
Sources
- SAE J404 — Chemical Compositions of SAE Alloy Steels — SAE International (2021)
- SAE J1268 — Hardenability Bands for Carbon and Alloy H Steels (86B45H) — SAE International (2019)
- ASTM A29/A29M — Steel Bars, Carbon and Alloy, Hot-Wrought — ASTM International (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 — ASM International (2013)
- Machinery's Handbook, 31st ed. — Industrial Press (2020)
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.