Steel SUM41 QT-352HB
Heat-treated state
JIS SUM41
QT-352HB = q&T
Maximum-strength condition; brittle and rarely used for structural parts because of sulfide-driven low toughness.
Values for the QT-352HB condition
Other SUM41 tempers and conditions
SUM41 is listed in 11 conditions; see the grade overview at SUM41.
Compare all 11 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
Hot rolled | Cheapest form, chosen for hot-forged blanks and parts that will be heat treated after machining. | 335 | 610 | 15 | 179 HB | — |
Solution annealed | Softest condition; pick it for deep drilling, cross-hole work, cold heading or maximum ductility before quenching. | 345 | 585 | 27 | 174 HB | — |
Normalized | Used to homogenize forgings and give uniform pearlitic structure before final machining or hardening. | 400 | 670 | 22.5 | 197 HB | — |
Q&T | Soft, tough quench-and-temper condition for shock-loaded shafts where ductility matters more than strength. | 400 | 605 | 28 | 13 HRC | 9.6 % IACS |
Cold Drawn, Stress Relieved | Choose when long slender turned parts must stay straight after heavy asymmetric machining. | 515 | 620 | 13 | 187 HB | — |
CDDefault Cold drawn | Standard stock condition for automatic-lathe and CNC turned parts needing good size tolerance and 650 MPa strength. | 565 | 655 | 10 | 197 HB | — |
Q&T | Balanced strength/toughness condition typical for automotive studs, levers and pins. | 565 | 705 | 24 | 20 HRC | 9.5 % IACS |
Induction hardened | Selective surface hardening of journals and cam faces where a wear-resistant skin over a tough core is needed. | 570 | 700 | 10 | 52 HRC | 9.4 % IACS |
Q&T | Higher-strength temper for loaded fasteners and shafts that are finish-ground after heat treatment. | 700 | 810 | 15 | 26 HRC | 9.3 % IACS |
Q&T | High-strength, lower-ductility temper for wear-loaded pins and small shafts. | 840 | 985 | 10 | 30 HRC | 9.1 % IACS |
QT-352HBThis page Q&T | Maximum-strength condition; brittle and rarely used for structural parts because of sulfide-driven low toughness. | 940 | 1,080 | 5 | 38 HRC | 8.8 % IACS |
What is SUM41 QT-352HB?
SUM41 QT-352HB is SUM41 heat treated to QT-352HB — maximum-strength condition; brittle and rarely used for structural parts because of sulfide-driven low toughness. SUM41 QT-352HB has a yield strength of 940 MPa (136 ksi) and a tensile strength of 1,080 MPa (157 ksi) — stronger than 91% of steel grades. Elongation at break is 5% and the elastic modulus is 205 GPa (29.7 Msi). SUM41 QT-352HB 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). CD is the default condition FabDigit quotes; QT-352HB is available on request or by drawing note.
Advantages
- Low embodied carbon — 1.9 kg CO₂/kg, better than 92% of steel grades
- High strength — 940 MPa (136 ksi), better than 91% of steel grades
Limitations
- Difficult to weld — 10/100, worse than 99% of steel grades
- Limited ductility — 5%, worse than 98% of steel grades
- Limited service temperature — 180°C (356 °F), worse than 98% of steel grades
- Limited formability — 8/100, worse than 97% of steel grades
- Hard to polish — 40/100, worse than 96% of steel grades
SUM41 QT-352HB properties
Typical room-temperature values for SUM41 QT-352HB; 22 are specific to this condition. Other listed values are SUM41 reference data and may not represent this condition. Bars are the position among steel grades.
Physical3
SUM41 QT-352HB 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
SUM41 QT-352HB has a yield strength of 940 MPa (136 ksi) and a tensile strength of 1,080 MPa (157 ksi) — stronger than 91% of steel grades. Elongation at break is 5% and the elastic modulus is 205 GPa (29.7 Msi).
Thermal6
SUM41 QT-352HB is rated for continuous service to 180°C (356 °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
SUM41 QT-352HB conducts electricity at 8.8 % IACS, better than 69% of steel grades.
Chemical & Environmental3
Corrosion resistance is not recommended (9/100), worse than 98% of steel grades.
Sustainability4
Producing a kilogram of SUM41 QT-352HB takes about 25 MJ of energy and emits 1.9 kg of CO₂ — less than 82% of steel grades. Typical recycled content is 30%.
Manufacturability6
SUM41 QT-352HB's machinability is fair (40/100, worse than 77% of steel grades); weldability not recommended (10/100); formability not recommended (8/100).
Values are nominal handbook figures for design screening. Confirm any required mill or lot documentation when quoting.
Working with SUM41 QT-352HB
Is SUM41 easy to machine?
Excellent for high-speed screw-machine and CNC turning — MnS breaks chips; run 20–30 % faster than 1045 and avoid feeds so light that inclusions smear.
Can SUM41 be welded?
Poor: 0.08–0.13 % S plus ~0.35 % C promotes hot cracking and porosity — avoid welded joints, or use low-hydrogen consumables with preheat 150–250 °C and PWHT.
Can SUM41 be formed, bent or molded?
Hot forge at 1050–1200 °C; cold bending and heading are limited by transverse ductility, so keep bend radii generous and orient stringers along the load path.
What surface finishes work on SUM41?
No inherent corrosion resistance — specify zinc, zinc-nickel or black oxide plus oil; phosphating works well, and sulfide stringers may show as fine streaks in polished or plated surfaces.
SUM41 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 |
|---|---|---|
| CJIS G 4804 SUM41 | 0.32 – 0.39 | 0.36 |
| Mn | 1.35 – 1.65 | 1.5 |
| P | ≤ 0.04 | 0.03 |
| Sfree-machining sulfur | 0.08 – 0.13 | 0.1 |
| Siusually not specified / low, killed practice may differ | ≤ 0.1 | 0.05 |
| Curesidual limit | ≤ 0.3 | 0.1 |
| Niresidual limit | ≤ 0.25 | 0.05 |
| Crresidual limit | ≤ 0.2 | 0.05 |
| Fe | balance | — |
SUM41 QT-352HB — frequently asked
What is SUM41 QT-352HB used for?
SUM41 QT-352HB is typically used for shafts, bolts and automotive fasteners. In short: medium-carbon free-cutting grade; stronger than SUM32; avoid welded joints.
What is the yield strength of SUM41 QT-352HB?
SUM41 QT-352HB has a typical yield strength of 940 MPa (136 ksi) and a tensile strength of 1,080 MPa (157 ksi) — stronger than 91% of steel grades. Strength varies by condition: see the 11 listed tempers.
Is SUM41 QT-352HB easy to machine?
Not especially — machinability is rated fair (40/100, worse than 77% of steel grades). Excellent for high-speed screw-machine and CNC turning — MnS breaks chips; run 20–30 % faster than 1045 and avoid feeds so light that inclusions smear.
Can SUM41 QT-352HB be welded?
Not readily — weldability is rated not recommended (10/100). Poor: 0.08–0.13 % S plus ~0.35 % C promotes hot cracking and porosity — avoid welded joints, or use low-hydrogen consumables with preheat 150–250 °C and PWHT.
What surface finishes work on SUM41 QT-352HB?
No inherent corrosion resistance — specify zinc, zinc-nickel or black oxide plus oil; phosphating works well, and sulfide stringers may show as fine streaks in polished or plated surfaces.
Can SUM41 QT-352HB be formed, bent or molded?
Hot forge at 1050–1200 °C; cold bending and heading are limited by transverse ductility, so keep bend radii generous and orient stringers along the load path.
What is the maximum service temperature of SUM41 QT-352HB?
SUM41 QT-352HB 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 SUM41-CD and SUM41-HR?
CD is the default condition — standard stock condition for automatic-lathe and CNC turned parts needing good size tolerance and 650 MPa strength. HR: cheapest form, chosen for hot-forged blanks and parts that will be heat treated after machining. Yield strength is 565 MPa in CD versus 335 MPa in HR.
Sources
- JIS G 4804 — Sulfur and sulfur-composite free-cutting steels — JSA (2019)
- SAE J403 / ASTM A29 — Carbon and resulfurized steel bars (1137) — SAE / ASTM (2020)
- ASM Handbook Vol.1 — Properties and Selection: Irons, Steels and High-Performance Alloys — ASM International (1990)
- ASM Handbook Vol.16 — Machining — ASM International (1989)
- JIS–AISI cross-reference and free-cutting steel property tables — MatWeb / JFE-Daido mill data (2023)
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.