Steel 41B17 QT-25
Hardness band
EN 41B17 · UNS G41171
QT-25 = q&T 22-28 HRC
Direct quench-and-temper without carburizing for shafts and fasteners needing tough medium strength.
Values for the QT-25 condition
Other 41B17 tempers and conditions
41B17 is listed in 7 conditions; see the grade overview at 41B17.
Compare all 7 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
ADefault Solution annealed | Standard supply condition for gear blanks and cold-headed parts prior to carburizing. | 315 | 480 | 30 | 143 HB | — |
Hot rolled | Cheapest stock form for parts that will be fully carburized or Q&T after machining. | 330 | 515 | 27 | 149 HB | — |
Normalized | Grain refinement and uniform structure before carburizing or for moderately loaded parts. | 360 | 560 | 27 | 163 HB | — |
Cold drawn | Choose for close-tolerance, good-surface bar in automatic screw machines; higher strength, lower ductility. | 505 | 590 | 15 | 174 HB | — |
QT-25This page Q&T 22-28 HRC | Direct quench-and-temper without carburizing for shafts and fasteners needing tough medium strength. | 660 | 830 | 18 | 25 HRC | — |
Carburized, quenched and tempered | Primary service condition: hard wear-resistant case with tough boron-hardened core for gears and sprockets. | 800 | 1,030 | 12 | 60 HRC | — |
Q&T 28-34 HRC | Higher-strength through-hardened condition for pins, links and drive components. | 830 | 1,000 | 15 | 31 HRC | — |
What is 41B17 QT-25?
41B17 QT-25 is 41B17 heat treated to QT-25 — direct quench-and-temper without carburizing for shafts and fasteners needing tough medium strength. 41B17 QT-25 has a yield strength of 660 MPa (95.7 ksi) and a tensile strength of 830 MPa (120 ksi) — stronger than 80% of steel grades. Elongation at break is 18% and the elastic modulus is 205 GPa (29.7 Msi). 41B17 QT-25 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-25 is available on request or by drawing note.
Advantages
- Forms and bends easily — 70/100, better than 86% of steel grades
- High strength — 660 MPa (95.7 ksi), better than 80% of steel grades
41B17 QT-25 properties
Typical room-temperature values for 41B17 QT-25; 12 are specific to this condition. Other listed values are 41B17 reference data and may not represent this condition. Bars are the position among steel grades.
Physical3
41B17 QT-25 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
41B17 QT-25 has a yield strength of 660 MPa (95.7 ksi) and a tensile strength of 830 MPa (120 ksi) — stronger than 80% of steel grades. Elongation at break is 18% and the elastic modulus is 205 GPa (29.7 Msi).
Thermal6
41B17 QT-25 is rated for continuous service to 425°C (797 °F). It conducts heat at 42 W/m·K (24.3 BTU/hr·ft·°F), worse than 56% of steel grades. Thermal expansion is 12.2 µm/m·K (6.78 µin/in·°F).
Electrical3
41B17 QT-25 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 41B17 QT-25 takes about 29 MJ of energy and emits 2.1 kg of CO₂ — less than 53% of steel grades. Typical recycled content is 30%.
Manufacturability7
41B17 QT-25's machinability is fair (52/100, better than 52% of steel grades); weldability good (60/100); formability very good (70/100).
Values are nominal handbook figures for design screening. Confirm any required mill or lot documentation when quoting.
Working with 41B17 QT-25
Is 41B17 easy to machine?
Machines like 4118/8620 at ~65 % of AISI 1212; best in spheroidize-annealed 140–180 HB with carbide tooling, and finish-machine before carburizing since the 58–62 HRC case needs grinding.
Can 41B17 be welded?
Weldable in the annealed/normalized condition with low-hydrogen consumables and 150–250 °C preheat, but boron narrows the HAZ toughness window; never weld after carburizing.
Can 41B17 be formed, bent or molded?
Good cold-heading and upsetting behavior in spheroidized bar; hot forge 1150–1230 °C and normalize afterwards to restore fine grain and boron hardenability.
What surface finishes work on 41B17?
Non-anodizable ferrous steel — protect with zinc or manganese phosphate, black oxide, zinc/zinc-nickel plating (bake to avoid hydrogen embrittlement) or oil; ground and honed for gear tooth surfaces.
41B17 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 |
|---|---|---|
| Ccarburizing carbon level | 0.15 – 0.2 | 0.17 |
| Mn | 0.75 – 1 | 0.88 |
| Si | 0.15 – 0.35 | 0.25 |
| Cr | 0.45 – 0.65 | 0.55 |
| Mo | 0.08 – 0.15 | 0.12 |
| Beffective (soluble) boron; requires Ti/Al nitrogen fixing | 5×10⁻⁴ – 0 | 0 |
| P | ≤ 0.04 | — |
| S | ≤ 0.04 | — |
| Fe | balance | — |
41B17 QT-25 — frequently asked
What is 41B17 QT-25 used for?
41B17 QT-25 is typically used for carburized gears, shafts and pins. In short: low-cost 8620 alternative; carburizing boron steel; good cold-heading formability.
What is the yield strength of 41B17 QT-25?
41B17 QT-25 has a typical yield strength of 660 MPa (95.7 ksi) and a tensile strength of 830 MPa (120 ksi) — stronger than 80% of steel grades. Strength varies by condition: see the 7 listed tempers.
Is 41B17 QT-25 easy to machine?
Reasonably — machinability is rated fair (52/100, better than 52% of steel grades). Machines like 4118/8620 at ~65 % of AISI 1212; best in spheroidize-annealed 140–180 HB with carbide tooling, and finish-machine before carburizing since the 58–62 HRC case needs grinding.
Can 41B17 QT-25 be welded?
Yes — weldability is rated good (60/100). Weldable in the annealed/normalized condition with low-hydrogen consumables and 150–250 °C preheat, but boron narrows the HAZ toughness window; never weld after carburizing.
What surface finishes work on 41B17 QT-25?
Non-anodizable ferrous steel — protect with zinc or manganese phosphate, black oxide, zinc/zinc-nickel plating (bake to avoid hydrogen embrittlement) or oil; ground and honed for gear tooth surfaces.
Can 41B17 QT-25 be formed, bent or molded?
Good cold-heading and upsetting behavior in spheroidized bar; hot forge 1150–1230 °C and normalize afterwards to restore fine grain and boron hardenability.
What is the maximum service temperature of 41B17 QT-25?
41B17 QT-25 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 41B17-A and 41B17 QT-32?
A is the default condition — standard supply condition for gear blanks and cold-headed parts prior to carburizing. QT-32: higher-strength through-hardened condition for pins, links and drive components. Yield strength is 315 MPa in A versus 830 MPa in QT-32.
Sources
- SAE J404 — Chemical Compositions of SAE Alloy Steels — SAE International (2021)
- SAE J1268 — Hardenability Bands for Boron H-Steels — SAE International (2018)
- 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 (boron hardenability, carburizing) — ASM International (2013)
- UNS G41171 alloy record — SAE/ASTM Unified Numbering System (2019)
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.