Steel 4161-SA (Spheroidize annealed)
Heat-treated state
AISI/SAE 4161 · UNS G41610
Choose for cold heading, deep drawing or heavy cold forming of this high-carbon grade.
Values for the SA condition
Other 4161 tempers and conditions
4161 is listed in 10 conditions; see the grade overview at 4161.
Compare all 10 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
SAThis page Spheroidize annealed | Choose for cold heading, deep drawing or heavy cold forming of this high-carbon grade. | 390 | 700 | 22 | 11 HRC | 8.1 % IACS |
ADefault Solution annealed | Softest supply condition for machining, cold forming and subsequent hardening by the user. | 415 | 760 | 18 | 217 HB | — |
Hot rolled | Lowest-cost mill condition for spring blanks and forging stock that will be heat treated afterwards. | 550 | 900 | 14 | 26 HRC | 7.8 % IACS |
Normalized | Uniform fine pearlitic structure for forgings prior to machining or hardening; higher strength than annealed. | 700 | 1,080 | 12 | 34 HRC | — |
Cold drawn | Bright, close-tolerance bar with raised yield strength for shafts machined without further heat treatment. | 760 | 900 | 10 | 26 HRC | 7.8 % IACS |
Q&T 650 °C | Softest Q&T condition — maximum ductility and machinability while retaining tempered-martensite structure. | 895 | 965 | 18 | 30 HRC | — |
Q&T 540 °C | Tough quenched-and-tempered condition for shock-loaded shafts and machined high-strength parts. | 1,145 | 1,240 | 14 | 38 HRC | — |
Q&T 425 °C | Typical leaf/coil spring and heavy shaft condition — best balance of fatigue strength and toughness. | 1,415 | 1,550 | 11 | 45 HRC | — |
Q&T 315 °C | Very high strength for heavily loaded springs and torsion bars where some ductility is still needed. | 1,620 | 1,855 | 8 | 53 HRC | — |
Q&T 205 °C | Maximum hardness and strength for wear-critical tooling; very low toughness, avoid notches and impact. | 1,725 | 2,035 | 6 | 57 HRC | — |
What is 4161-SA?
4161-SA is 4161 heat treated to SA — choose for cold heading, deep drawing or heavy cold forming of this high-carbon grade. 4161-SA has a yield strength of 390 MPa (56.6 ksi) and a tensile strength of 700 MPa (102 ksi) — weaker than 64% of steel grades. Elongation at break is 22% and the elastic modulus is 205 GPa (29.7 Msi). 4161-SA has a density of 7.85 g/cm³ (0.284 lb/in³), heavier than 56% of steel grades. It melts at 1,416°C (2,581 °F). A is the default condition FabDigit quotes; SA is available on request or by drawing note.
Limitations
- Difficult to weld — 22/100, worse than 81% of steel grades
4161-SA properties
Typical room-temperature values for 4161-SA; 23 are specific to this condition. Other listed values are 4161 reference data and may not represent this condition. Bars are the position among steel grades.
Physical3
4161-SA has a density of 7.85 g/cm³ (0.284 lb/in³), heavier than 56% of steel grades. It melts at 1,416°C (2,581 °F).
Mechanical16
4161-SA has a yield strength of 390 MPa (56.6 ksi) and a tensile strength of 700 MPa (102 ksi) — weaker than 64% of steel grades. Elongation at break is 22% and the elastic modulus is 205 GPa (29.7 Msi).
Thermal6
4161-SA is rated for continuous service to 400°C (752 °F). It conducts heat at 43.5 W/m·K (25.1 BTU/hr·ft·°F), better than 52% of steel grades. Thermal expansion is 12.3 µm/m·K (6.83 µin/in·°F).
Electrical3
4161-SA conducts electricity at 8.1 % IACS, better than 61% of steel grades.
Chemical & Environmental3
Corrosion resistance is not recommended (11/100), worse than 73% of steel grades.
Sustainability4
Producing a kilogram of 4161-SA takes about 30 MJ of energy and emits 2.2 kg of CO₂ — more than 56% of steel grades. Typical recycled content is 30%.
Manufacturability7
4161-SA's machinability is fair (53/100, better than 53% of steel grades); weldability poor (22/100); formability fair (45/100).
Values are nominal handbook figures for design screening. Confirm any required mill or lot documentation when quoting.
Working with 4161-SA
Is 4161 easy to machine?
Machine in the annealed/spheroidized state (~55 % of 1212); above 40 HRC use carbide or CBN with rigid setups, or finish by grinding.
Can 4161 be welded?
Poor weldability — CE ≈ 0.95; if unavoidable, preheat 300–350 °C, use low-hydrogen consumables and temper immediately after welding.
Can 4161 be formed, bent or molded?
Cold form only in spheroidize-annealed condition with generous radii; hot forge 1100–1200 °C and always normalize/anneal afterwards; oil quench from 830–860 °C and temper at once to avoid quench cracking.
What surface finishes work on 4161?
No anodizing; use black oxide, manganese phosphate + oil, zinc or Cr plating (bake 190 °C ≥4 h after plating to avoid hydrogen embrittlement); shot peening greatly boosts spring fatigue life.
4161 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 |
|---|---|---|
| Chighest carbon of the 41xx family | 0.56 – 0.64 | 0.6 |
| Mn | 0.75 – 1 | 0.88 |
| Si | 0.15 – 0.35 | 0.25 |
| Cr | 0.7 – 0.9 | 0.8 |
| Mo | 0.25 – 0.35 | 0.3 |
| P | ≤ 0.04 | — |
| S | ≤ 0.04 | — |
| Fe | balance | — |
4161-SA — frequently asked
What is 4161-SA used for?
4161-SA is typically used for heavy springs, high-strength shafts and gears. In short: highest-carbon 41xx grade; spring-strength Cr-Mo steel; very limited weldability.
What is the yield strength of 4161-SA?
4161-SA has a typical yield strength of 390 MPa (56.6 ksi) and a tensile strength of 700 MPa (102 ksi) — weaker than 64% of steel grades. Strength varies by condition: see the 10 listed tempers.
Is 4161-SA easy to machine?
Reasonably — machinability is rated fair (53/100, better than 53% of steel grades). Machine in the annealed/spheroidized state (~55 % of 1212); above 40 HRC use carbide or CBN with rigid setups, or finish by grinding.
Can 4161-SA be welded?
Not readily — weldability is rated poor (22/100). Poor weldability — CE ≈ 0.95; if unavoidable, preheat 300–350 °C, use low-hydrogen consumables and temper immediately after welding.
What surface finishes work on 4161-SA?
No anodizing; use black oxide, manganese phosphate + oil, zinc or Cr plating (bake 190 °C ≥4 h after plating to avoid hydrogen embrittlement); shot peening greatly boosts spring fatigue life.
Can 4161-SA be formed, bent or molded?
Cold form only in spheroidize-annealed condition with generous radii; hot forge 1100–1200 °C and always normalize/anneal afterwards; oil quench from 830–860 °C and temper at once to avoid quench cracking.
What is the maximum service temperature of 4161-SA?
4161-SA is rated for continuous use to about 400°C (752 °F). Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
What is the difference between 4161-A and 4161-QT205?
A is the default condition — softest supply condition for machining, cold forming and subsequent hardening by the user. QT205: maximum hardness and strength for wear-critical tooling; very low toughness, avoid notches and impact. Yield strength is 415 MPa in A versus 1,725 MPa in QT205.
Sources
- SAE J404 — Chemical Compositions of SAE Alloy Steels — SAE International (2021)
- SAE J1268 — Hardenability Bands for Carbon and Alloy H Steels — 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.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.