Steel 1042
AISI/SAE 1042 · UNS G10420
1042 is a medium-carbon steel (UNS G10420) with slightly higher carbon than 1040, giving increased strength and hardenability for quench-and-tempered machine parts.
Reference datasheet — 1042 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
1042 tempers and conditions
1042 is supplied in 9 conditions, soft to hard. CD is the default FabDigit quotes; the values on this page are for it.
Compare all 9 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
Hot rolled | Lowest-cost supply condition for parts that will be machined all over or heat treated afterwards. | 305 | 550 | 18 | 156 HB | — |
Solution annealed | Softest condition — pick for deep machining, cold forming or before a final quench-and-temper cycle. | 360 | 545 | 26 | 149 HB | — |
Normalized | Refines grain and homogenizes forgings/hot-rolled stock; good general-purpose strength-toughness balance before machining. | 400 | 610 | 22 | 179 HB | — |
CDDefault Cold drawn | Standard stocked bar condition: higher strength, tight size tolerance and good machined finish for shafts and pins. | 540 | 635 | 12 | 187 HB | — |
Normalized then cold drawn | Choose when a uniform normalized microstructure plus cold-drawn strength and straightness is required (shafting, hydraulic rod stock). | 585 | 690 | 12 | 197 HB | 10 % IACS |
Q&T 540 °C | General machine-part condition combining ~800 MPa strength with useful ductility and impact toughness. | 620 | 800 | 20 | 22 HRC | — |
Induction hardened | Select when a wear-resistant 55+ HRC case with a tough core is needed on shafts, journals and gear teeth. | 620 | 800 | 16 | 56 HRC | — |
quenched and tempered to 28–32 HRC | Commonly specified hardness band for gears, shafts and couplings that must still be machinable. | 800 | 965 | 16 | 30 HRC | — |
Q&T 315 °C | Maximum practical strength condition for small sections; low ductility and poor weldability. | 980 | 1,180 | 11 | 39 HRC | — |
What is 1042?
1042 is a medium-carbon steel (UNS G10420) with slightly higher carbon than 1040, giving increased strength and hardenability for quench-and-tempered machine parts. Cold-drawn bar runs about 540 MPa yield, 635 MPa tensile, 12 % elongation and 187 HB (90 HRB); normalized-plus-cold-drawn, annealed, Q&T (including 315 °C and 540 °C tempers and a 28–32 HRC band) and induction-hardened conditions are on file. Cold formability is poor and weldability is the weakest of the plain-carbon group (CE ≈ 0.55–0.65), needing preheat and post-weld stress relief; use 1020 for weldments. 1042 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). 1042 has a yield strength of 540 MPa (78.3 ksi) and a tensile strength of 635 MPa (92.1 ksi) — stronger than 70% of steel grades. Elongation at break is 12% and the elastic modulus is 200 GPa (29 Msi).
What is 1042 used for?
- Shafts
- Gears
- Bolts
- Machine parts
Advantages
- Low embodied carbon — 1.9 kg CO₂/kg, better than 92% of steel grades
- High electrical conductivity — 10.7 % IACS, better than 91% of steel grades
- Easy to machine — 62/100, better than 89% of steel grades
- Conducts heat well — 49.8 W/m·K (28.8 BTU/hr·ft·°F), better than 85% of steel grades
Limitations
- Limited ductility — 12%, worse than 84% of steel grades
- Low fracture toughness — 55 MPa·√m (50.1 ksi·√in), worse than 82% of steel grades
1042 properties
Typical room-temperature values for 1042-CD; bars are the position among steel grades.
Physical3
1042 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).
Mechanical16
1042 has a yield strength of 540 MPa (78.3 ksi) and a tensile strength of 635 MPa (92.1 ksi) — stronger than 70% of steel grades. Elongation at break is 12% and the elastic modulus is 200 GPa (29 Msi).
Thermal6
1042 is rated for continuous service to 400°C (752 °F). It conducts heat at 49.8 W/m·K (28.8 BTU/hr·ft·°F), better than 85% of steel grades. Thermal expansion is 11.7 µm/m·K (6.5 µin/in·°F).
Electrical3
1042 conducts electricity at 10.7 % IACS, better than 91% of steel grades.
Chemical & Environmental3
Corrosion resistance is not recommended (10/100), worse than 86% of steel grades.
Sustainability4
Producing a kilogram of 1042 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
1042's machinability is good (62/100, better than 89% of steel grades); weldability fair (40/100); 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. 1042 is highlighted; hover a dot for its name, or open the interactive family chart.
Working with 1042
Is 1042 easy to machine?
Machines well at ~60 % of 1212 with carbide tooling and flood coolant; cold-drawn or normalized stock gives the cleanest finish, Q&T above 30 HRC needs reduced speeds.
Can 1042 be welded?
Carbon equivalent ~0.55–0.65 — preheat 150–260 °C, low-hydrogen consumables and post-weld stress relief/temper are needed to avoid HAZ cracking.
Can 1042 be formed, bent or molded?
Limited cold formability; bend on generous radii in the annealed condition, otherwise hot form at 1100–1200 °C and normalize afterwards.
1042 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 |
|---|---|---|
| CSAE J403 / ASTM A29 heat analysis | 0.4 – 0.47 | 0.43 |
| Mn | 0.6 – 0.9 | 0.75 |
| P | ≤ 0.03 | 0.02 |
| S | ≤ 0.05 | 0.03 |
| Sitypical for killed steel; not specified for all deoxidation practices | 0.15 – 0.35 | 0.25 |
| Fe | balance |
What surface finishes work on 1042?
No corrosion resistance of its own — protect with paint, black oxide, phosphate, zinc plating or nitro-carburizing; polishes to a fair bright finish.
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 1042 in FabDigit's catalog. Equivalence is nominal — check the exact specification when certification matters.
- UNS
- G10420
How much does 1042 cost?
1042 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.
1042 — frequently asked
What is 1042 used for?
1042 is typically used for shafts, gears, bolts and machine parts. In short: higher strength than 1040; quench-and-temper machine steel; poor cold formability.
What is the yield strength of 1042?
1042 has a typical yield strength of 540 MPa (78.3 ksi) and a tensile strength of 635 MPa (92.1 ksi) — stronger than 70% of steel grades. Strength varies by condition: see the 9 listed tempers.
Is 1042 easy to machine?
Reasonably — machinability is rated good (62/100, better than 89% of steel grades). Machines well at ~60 % of 1212 with carbide tooling and flood coolant; cold-drawn or normalized stock gives the cleanest finish, Q&T above 30 HRC needs reduced speeds.
Can 1042 be welded?
With care — weldability is rated fair (40/100). Carbon equivalent ~0.55–0.65 — preheat 150–260 °C, low-hydrogen consumables and post-weld stress relief/temper are needed to avoid HAZ cracking.
What surface finishes work on 1042?
No corrosion resistance of its own — protect with paint, black oxide, phosphate, zinc plating or nitro-carburizing; polishes to a fair bright finish.
Can 1042 be formed, bent or molded?
Limited cold formability; bend on generous radii in the annealed condition, otherwise hot form at 1100–1200 °C and normalize afterwards.
What is the maximum service temperature of 1042?
1042 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 1042-CD and 1042 QT-315?
CD is the default condition — standard stocked bar condition: higher strength, tight size tolerance and good machined finish for shafts and pins. QT-315: maximum practical strength condition for small sections; low ductility and poor weldability. Yield strength is 540 MPa in CD versus 980 MPa in QT-315.
How much does 1042 cost?
1042 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 J403 — Chemical Compositions of SAE Carbon Steels — SAE International (2014)
- ASTM A29/A29M — Steel Bars, Carbon and Alloy, Hot-Wrought — ASTM (2020)
- ASTM A108 — Steel Bar, Carbon and Alloy, Cold-Finished — ASTM (2018)
- 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)
- Machinery's Handbook, 31st ed. — 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.