Steel 1042 QT-315
Heat-treated state
AISI/SAE 1042 · UNS G10420
QT-315 = q&T 315 °C
Maximum practical strength condition for small sections; low ductility and poor weldability.
Values for the QT-315 condition
Other 1042 tempers and conditions
1042 is listed in 9 conditions; see the grade overview at 1042.
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 | — |
QT-315This page 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 QT-315?
1042 QT-315 is 1042 heat treated to QT-315 — maximum practical strength condition for small sections; low ductility and poor weldability. 1042 QT-315 has a yield strength of 980 MPa (142 ksi) and a tensile strength of 1,180 MPa (171 ksi) — stronger than 91% of steel grades. Elongation at break is 11% and the elastic modulus is 200 GPa (29 Msi). 1042 QT-315 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). CD is the default condition FabDigit quotes; QT-315 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 — 980 MPa (142 ksi), better than 91% of steel grades
- High electrical conductivity — 10.7 % IACS, better than 91% of steel grades
- Conducts heat well — 49.8 W/m·K (28.8 BTU/hr·ft·°F), better than 85% of steel grades
Limitations
- Difficult to weld — 15/100, worse than 91% of steel grades
- Limited ductility — 11%, worse than 89% of steel grades
- Difficult to machine — 32/100, worse than 87% of steel grades
- Low fracture toughness — 55 MPa·√m (50.1 ksi·√in), worse than 82% of steel grades
1042 QT-315 properties
Typical room-temperature values for 1042 QT-315; 13 are specific to this condition. Other listed values are 1042 reference data and may not represent this condition. Bars are the position among steel grades.
Physical3
1042 QT-315 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 QT-315 has a yield strength of 980 MPa (142 ksi) and a tensile strength of 1,180 MPa (171 ksi) — stronger than 91% of steel grades. Elongation at break is 11% and the elastic modulus is 200 GPa (29 Msi).
Thermal6
1042 QT-315 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 QT-315 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 QT-315 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 QT-315's machinability is poor (32/100, worse than 87% of steel grades); weldability poor (15/100); formability poor (30/100).
Values are nominal handbook figures for design screening. Confirm any required mill or lot documentation when quoting.
Working with 1042 QT-315
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.
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.
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 | — |
1042 QT-315 — frequently asked
What is 1042 QT-315 used for?
1042 QT-315 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 QT-315?
1042 QT-315 has a typical yield strength of 980 MPa (142 ksi) and a tensile strength of 1,180 MPa (171 ksi) — stronger than 91% of steel grades. Strength varies by condition: see the 9 listed tempers.
Is 1042 QT-315 easy to machine?
Not especially — machinability is rated poor (32/100, worse than 87% 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 QT-315 be welded?
Not readily — weldability is rated poor (15/100). 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 QT-315?
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 QT-315 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 QT-315?
1042 QT-315 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.
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. Nothing on this page is a certification — request mill certs, CoC or material test reports with your order.