Steel 4024
AISI/SAE 4024 · UNS G40240
4024 is the resulfurized free-machining version of 4023 molybdenum alloy steel (UNS G40240), with 0.035–0.050 % S added as manganese sulfide inclusions to break chips.
Reference datasheet — 4024 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 HR condition
4024 tempers and conditions
4024 is supplied in 7 conditions, soft to hard. HR is the default FabDigit quotes; the values on this page are for it.
Compare all 7 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
Solution annealed | Pick when maximum cold formability or the softest structure before deep machining is wanted. | 290 | 450 | 30 | 131 HB | 8 % IACS |
HRDefault Hot rolled | Lowest-cost stock condition for parts that will be machined and then carburized. | 330 | 490 | 25 | 143 HB | — |
Normalized | Uniform fine-grained structure before carburizing; better machined-surface finish than as-rolled. | 370 | 530 | 27 | 156 HB | 7.8 % IACS |
Cold drawn, stress relieved | Use when machining-induced distortion must be minimized on long slender parts. | 450 | 550 | 18 | 166 HB | 7.8 % IACS |
Cold drawn | Choose for close size tolerance, bright finish and higher yield strength on screw-machine parts. | 490 | 580 | 15 | 174 HB | — |
Q&T | Through-hardened option when uniform core strength rather than a hard case is required. | 540 | 700 | 18 | 15 HRC | 7.8 % IACS |
Carburized, quenched and tempered | Primary end-use condition: hard wear-resistant case over a tough moderate-strength core for pins, gears and bushings. | 560 | 800 | 13 | 60 HRC | — |
What is 4024?
4024 is the resulfurized free-machining version of 4023 molybdenum alloy steel (UNS G40240), with 0.035–0.050 % S added as manganese sulfide inclusions to break chips. It is specified when machinability governs — machinability score 72 against 65 for 4023 — while still delivering moderate strength of about 330 MPa yield, 490 MPa tensile, 25 % elongation and 143 HB (78 HRB); typical forms are hot-rolled, annealed, normalized, cold-drawn and stress-relieved bar, carburized parts and quenched-and-tempered stock at about 200 HB. The sulfur makes it prone to hot cracking in welding and reduces transverse ductility, so use 4023 where welding or heavy forming is required. 4024 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). 4024 has a yield strength of 330 MPa (47.9 ksi) and a tensile strength of 490 MPa (71.1 ksi) — weaker than 78% of steel grades. Elongation at break is 25% and the elastic modulus is 205 GPa (29.7 Msi).
What is 4024 used for?
- automatic screw-machine parts
- shafts
- fittings
Advantages
- Easy to machine — 72/100, better than 97% of steel grades
- Ductile — tolerates forming and impact — 25%, better than 77% of steel grades
Limitations
- Hard to polish — 45/100, worse than 84% of steel grades
- Low strength — 330 MPa (47.9 ksi), worse than 78% of steel grades
4024 properties
Typical room-temperature values for 4024-HR; bars are the position among steel grades.
Physical3
4024 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).
Mechanical13
4024 has a yield strength of 330 MPa (47.9 ksi) and a tensile strength of 490 MPa (71.1 ksi) — weaker than 78% of steel grades. Elongation at break is 25% and the elastic modulus is 205 GPa (29.7 Msi).
Thermal6
4024 is rated for continuous service to 400°C (752 °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
4024 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 4024 takes about 30 MJ of energy and emits 2.1 kg of CO₂ — more than 56% of steel grades. Typical recycled content is 30%.
Manufacturability7
4024's machinability is very good (72/100, better than 97% of steel grades); weldability fair (35/100); formability good (55/100).
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. 4024 is highlighted; hover a dot for its name, or open the interactive family chart.
Working with 4024
Is 4024 easy to machine?
Excellent for high-volume screw-machine work — MnS inclusions break chips; run 20–30 % higher speed than 4023 with carbide and sulfur-bearing cutting oil.
Can 4024 be welded?
Marginal: the 0.035–0.050 % S promotes hot cracking; if welding is unavoidable use low-hydrogen filler, 150–200 °C preheat and post-weld stress relief, or specify 4023 instead.
Can 4024 be formed, bent or molded?
Good longitudinal cold heading/bending in the annealed state, but keep bend axes across the rolling direction — transverse ductility is reduced by sulfide stringers.
4024 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 |
|---|---|---|
| C | 0.2 – 0.25 | 0.23 |
| Mn | 0.7 – 0.9 | 0.8 |
| Si | 0.15 – 0.35 | 0.25 |
| Mo | 0.2 – 0.3 | 0.25 |
| Sintentional resulfurizing for free machining | 0.04 – 0.05 | 0.04 |
| P | ≤ 0.04 | |
| Fe | balance |
What surface finishes work on 4024?
Not anodizable; protect with zinc or nickel plating, black oxide or phosphate-and-oil. Sulfide pull-out limits mirror polishing and can leave micro-pits in 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 4024 in FabDigit's catalog. Equivalence is nominal — check the exact specification when certification matters.
- UNS
- G40240
How much does 4024 cost?
4024 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.
4024 — frequently asked
What is 4024 used for?
4024 is typically used for automatic screw-machine parts, shafts and fittings. In short: free-machining 4023 variant; best-machining moly steel; high-volume turning grade.
What is the yield strength of 4024?
4024 has a typical yield strength of 330 MPa (47.9 ksi) and a tensile strength of 490 MPa (71.1 ksi) — weaker than 78% of steel grades. Strength varies by condition: see the 7 listed tempers.
Is 4024 easy to machine?
Yes — machinability is rated very good (72/100, better than 97% of steel grades). Excellent for high-volume screw-machine work — MnS inclusions break chips; run 20–30 % higher speed than 4023 with carbide and sulfur-bearing cutting oil.
Can 4024 be welded?
With care — weldability is rated fair (35/100). Marginal: the 0.035–0.050 % S promotes hot cracking; if welding is unavoidable use low-hydrogen filler, 150–200 °C preheat and post-weld stress relief, or specify 4023 instead.
What surface finishes work on 4024?
Not anodizable; protect with zinc or nickel plating, black oxide or phosphate-and-oil. Sulfide pull-out limits mirror polishing and can leave micro-pits in plated surfaces.
Can 4024 be formed, bent or molded?
Good longitudinal cold heading/bending in the annealed state, but keep bend axes across the rolling direction — transverse ductility is reduced by sulfide stringers.
What is the maximum service temperature of 4024?
4024 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 4024-HR and 4024 CARB?
HR is the default condition — lowest-cost stock condition for parts that will be machined and then carburized. CARB: primary end-use condition: hard wear-resistant case over a tough moderate-strength core for pins, gears and bushings. Yield strength is 330 MPa in HR versus 560 MPa in CARB.
How much does 4024 cost?
4024 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
- SAE J404 — Chemical Compositions of SAE Alloy Steels — SAE International (2021)
- SAE J1268 / ASTM A29-A29M Alloy Steel Bars — 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 (Carburizing of low-alloy steels) — ASM International (1991)
- Machinery's Handbook, machinability ratings for resulfurized alloy steels — Industrial Press (2020)
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.