Steel SUM41
JIS SUM41
SUM41 is a medium-carbon resulfurized free-machining steel comparable to AISI 1137, with around 0.35 % carbon and 0.08–0.13 % sulfur for strength together with chip breaking.
Reference datasheet — SUM41 is not in the instant-quote catalog. Upload your part and an engineer will quote it in this grade or suggest the closest stocked equivalent.
Values for the CD condition
SUM41 tempers and conditions
SUM41 is supplied in 11 conditions, soft to hard. CD is the default FabDigit quotes; the values on this page are for it.
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 |
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?
SUM41 is a medium-carbon resulfurized free-machining steel comparable to AISI 1137, with around 0.35 % carbon and 0.08–0.13 % sulfur for strength together with chip breaking. It suits high-volume turned and forged parts such as shafts, bolts and automotive fasteners, and is supplied cold-drawn, hot-rolled, normalized, annealed, stress-relieved, induction-hardened and quench-and-tempered from 197 to 352 HB. Cold-drawn bar gives about 565 MPa yield, 655 MPa tensile, 10 % elongation and 197 HB at a machinability rating of 78. Welding is not recommended and cold heading is limited; SUM43 (1141) is the stronger next step. SUM41 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). SUM41 has a yield strength of 565 MPa (81.9 ksi) and a tensile strength of 655 MPa (95 ksi) — stronger than 73% of steel grades. Elongation at break is 10% and the elastic modulus is 205 GPa (29.7 Msi).
What is SUM41 used for?
- Shafts
- Bolts
- Automotive fasteners
Advantages
- Easy to machine — 78/100, better than 97% of steel grades
- Low embodied carbon — 1.9 kg CO₂/kg, better than 92% of steel grades
- Conducts heat well — 49 W/m·K (28.3 BTU/hr·ft·°F), better than 83% of steel grades
- High electrical conductivity — 9.6 % IACS, better than 78% of steel grades
Limitations
- Hard to polish — 40/100, worse than 96% of steel grades
- Limited ductility — 10%, worse than 91% of steel grades
- Low fracture toughness — 55 MPa·√m (50.1 ksi·√in), worse than 82% of steel grades
- Difficult to weld — 25/100, worse than 77% of steel grades
SUM41 properties
Typical room-temperature values for SUM41-CD; bars are the position among steel grades.
Physical3
SUM41 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 has a yield strength of 565 MPa (81.9 ksi) and a tensile strength of 655 MPa (95 ksi) — stronger than 73% of steel grades. Elongation at break is 10% and the elastic modulus is 205 GPa (29.7 Msi).
Thermal6
SUM41 is rated for continuous service to 350°C (662 °F). It conducts heat at 49 W/m·K (28.3 BTU/hr·ft·°F), better than 83% of steel grades. Thermal expansion is 11.9 µm/m·K (6.61 µin/in·°F).
Electrical3
SUM41 conducts electricity at 9.6 % IACS, better than 78% of steel grades.
Chemical & Environmental3
Corrosion resistance is not recommended (9/100), worse than 98% of steel grades.
Sustainability4
Producing a kilogram of SUM41 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's machinability is very good (78/100, better than 97% of steel grades); weldability poor (25/100); formability poor (30/100).
Common Calculations5
Values are nominal handbook figures for design screening. Certified mill or lot data ships with every FabDigit order on request.
Strength versus weight in the steel family
Yield strength against density for every steel grade FabDigit runs. SUM41 is highlighted; hover a dot for its name, or open the interactive family chart.
Working with SUM41
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.
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 |
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.
Surface treatments FabDigit runs on steel parts — pick them in the quote configurator or call them out on the drawing. Each links to its datasheet in the surface-finish library (thickness, specs, call-out, material verdicts).
Organic Coating
Black / Phosphate
Thermal Spray
Equivalent designations
Standards and trade names that resolve to Steel SUM41 in FabDigit's catalog. Equivalence is nominal — check the exact specification when certification matters.
- Similar grades
- 1137
How much does SUM41 cost?
SUM41 is a budget-cost steel ($), cheaper than about 90% of the materials FabDigit quotes. Part price depends far more on geometry, tolerance and quantity than on the raw stock — upload a CAD file for a live quote.
SUM41 — frequently asked
What is SUM41 used for?
SUM41 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?
SUM41 has a typical yield strength of 565 MPa (81.9 ksi) and a tensile strength of 655 MPa (95 ksi) — stronger than 73% of steel grades. Strength varies by condition: see the 11 listed tempers.
Is SUM41 easy to machine?
Yes — machinability is rated very good (78/100, better than 97% 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 be welded?
Not readily — weldability is rated poor (25/100). 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?
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 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?
SUM41 is rated for continuous use to about 350°C (662 °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.
How much does SUM41 cost?
SUM41 is a budget-cost steel ($), cheaper than about 90% of the materials FabDigit quotes. Part price depends far more on geometry, tolerance and quantity than on the raw stock — upload a CAD file for a live quote.
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; hardness values on non-Brinell scales are converted approximately for charting only. Manufacturability limits are FabDigit quote-engine defaults and may be relaxed by engineering review. Nothing on this page is a certification — request mill certs, CoC or material test reports with your order.