Steel 1030 · hardness band
Steel 1030 Q&T-425
Properties of the Q&T-425 condition, compared with the other 1030 tempers.
Mid-range temper when ~730 MPa tensile with useful ductility is required, e.g. medium-duty shafts and pins.
What is 1030 Q&T-425?
1030 Q&T-425 is 1030 heat treated to Q&T-425 — mid-range temper when ~730 MPa tensile with useful ductility is required, e.g. medium-duty shafts and pins. 1030 Q&T-425 has a yield strength of 579 MPa (84 ksi) and a tensile strength of 731 MPa (106 ksi) — stronger than 75% of steel grades. Elongation at break is 23% and the elastic modulus is 205 GPa (29.7 Msi). 1030 Q&T-425 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). HR is the default condition FabDigit quotes; Q&T-425 is available on request or by drawing note.
Advantages
- Conducts heat well — 51.9 W/m·K (30 BTU/hr·ft·°F), better than 96% of steel grades
- Low embodied carbon — 1.9 kg CO₂/kg, better than 92% of steel grades
- High electrical conductivity — 10 % IACS, better than 82% of steel grades
- High strength — 579 MPa (84 ksi), better than 75% of steel grades
Limitations
- Low fracture toughness — 55 MPa·√m (50.1 ksi·√in), worse than 83% of steel grades
1030 Q&T-425 properties
Typical room-temperature values for 1030 Q&T-425 — 9 properties are specific to this condition; the rest are grade-level values shared by every 1030 temper. Each bar shows where the value sits among the steel grades in FabDigit's library — further right is higher.
Physical3
1030 Q&T-425 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).
Mechanical15
1030 Q&T-425 has a yield strength of 579 MPa (84 ksi) and a tensile strength of 731 MPa (106 ksi) — stronger than 75% of steel grades. Elongation at break is 23% and the elastic modulus is 205 GPa (29.7 Msi).
Thermal6
1030 Q&T-425 is rated for continuous service to 400°C (752 °F). It conducts heat at 51.9 W/m·K (30 BTU/hr·ft·°F), better than 96% of steel grades. Thermal expansion is 11.7 µm/m·K (6.5 µin/in·°F).
Electrical3
1030 Q&T-425 conducts electricity at 10 % IACS, better than 82% of steel grades.
Chemical & Environmental3
Corrosion resistance is not recommended (10/100), worse than 87% of steel grades.
Sustainability4
Producing a kilogram of 1030 Q&T-425 takes about 25 MJ of energy and emits 1.9 kg of CO₂ — less than 82% of steel grades. Typical recycled content is 30%.
Manufacturability7
1030 Q&T-425's machinability is good (55/100, better than 62% of steel grades); weldability good (62/100); formability fair (50/100).
Values are nominal handbook figures for design screening. Certified mill or lot data ships with every FabDigit order on request.
Other 1030 tempers and conditions
1030 is also supplied in 9 other conditions. The full side-by-side table is on the 1030 overview.
- HRDefaultDefault, cheapest condition for weldments, brackets and forging/machining stock where tolerances and surface are not critical.260 MPa yield · 137 HB
- Q&T-205Maximum-hardness condition for thin, wear-loaded parts; low ductility and notch sensitivity, hardenable only in small sections.648 MPa yield · 49 HRC
- Q&T-425Mid-range temper when ~730 MPa tensile with useful ductility is required, e.g. medium-duty shafts and pins.579 MPa yield · 31 HRC
- Q&TGeneral-purpose quenched-and-tempered condition: ~670 MPa tensile with high ductility and toughness for shafts, links and fasteners.517 MPa yield · 25 HRC
- CRPick for sheet/strip needing good surface and thickness tolerance; strength raised by rolling, ductility reduced.460 MPa yield · 160 HB
- Q&T-650High-temper, high-toughness condition close to normalized strength; used where impact and machinability matter more than strength.441 MPa yield · 207 HB
- CDChoose for as-supplied shafting, studs and screw-machine parts: tight tolerance, bright finish and ~440 MPa yield without heat treatment.440 MPa yield · 149 HB
- IHSelect when a wear-resistant 50 HRC case on a tough core is needed — 1030's carbon level suits induction-hardened journals and tracks.360 MPa yield · 50 HRC
- NormalizedUniform fine-grain structure with balanced strength and toughness — standard condition for forgings and pre-machining stock.345 MPa yield · 149 HB
- AnnealedSoftest and most ductile condition — use before heavy cold forming, deep machining or to relieve prior work hardening.341 MPa yield · 126 HB
Working with 1030 Q&T-425
Is 1030 easy to machine?
Machines readily at ~70 % of 1212 in the cold-drawn or normalized state; anneal or normalize before heavy cuts, use positive-rake carbide and coolant, and avoid gummy chips in the fully annealed condition.
Can 1030 be welded?
Weldable by SMAW/GMAW with E70xx/ER70S filler; carbon ~0.30 % means preheat 100–200 °C for sections above ~20 mm plus post-weld stress relief, and re-heat-treatment if the part was Q&T.
Can 1030 be formed, bent or molded?
Cold bend and hot forge freely in the annealed/hot-rolled state (forging 1100–1230 °C); cold-drawn and Q&T material has limited bend radius and should be normalized before severe forming.
What surface finishes work on 1030?
No inherent corrosion protection — specify phosphate + oil, black oxide, zinc/zinc-nickel plating, hot-dip galvanizing or paint; takes a good ground/polished finish for shafting but will rust unplated.
1030 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 | 0.28 – 0.34 | 0.31 |
| Mn | 0.6 – 0.9 | 0.75 |
| P | ≤ 0.04 | 0.02 |
| S | ≤ 0.05 | 0.03 |
| Sinot specified by SAE for 10xx bar; typical for killed steel / DIN C30 | 0.15 – 0.35 | 0.25 |
| Fe | balance | — |
1030 Q&T-425 — frequently asked
What is 1030 Q&T-425 used for?
1030 Q&T-425 is typically used for forged axles, machinery shafts and bolts. In short: versatile medium-carbon.
What is the yield strength of 1030 Q&T-425?
1030 Q&T-425 has a typical yield strength of 579 MPa (84 ksi) and a tensile strength of 731 MPa (106 ksi) — stronger than 75% of steel grades. Strength varies by condition: see the 10 listed tempers.
Is 1030 Q&T-425 easy to machine?
Reasonably — machinability is rated good (55/100, better than 62% of steel grades). Machines readily at ~70 % of 1212 in the cold-drawn or normalized state; anneal or normalize before heavy cuts, use positive-rake carbide and coolant, and avoid gummy chips in the fully annealed condition.
Can 1030 Q&T-425 be welded?
Yes — weldability is rated good (62/100). Weldable by SMAW/GMAW with E70xx/ER70S filler; carbon ~0.30 % means preheat 100–200 °C for sections above ~20 mm plus post-weld stress relief, and re-heat-treatment if the part was Q&T.
What surface finishes work on 1030 Q&T-425?
No inherent corrosion protection — specify phosphate + oil, black oxide, zinc/zinc-nickel plating, hot-dip galvanizing or paint; takes a good ground/polished finish for shafting but will rust unplated.
Can 1030 Q&T-425 be formed, bent or molded?
Cold bend and hot forge freely in the annealed/hot-rolled state (forging 1100–1230 °C); cold-drawn and Q&T material has limited bend radius and should be normalized before severe forming.
What is the maximum service temperature of 1030 Q&T-425?
1030 Q&T-425 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 1030-HR and 1030-CR?
HR is the default condition — default, cheapest condition for weldments, brackets and forging/machining stock where tolerances and surface are not critical. CR: pick for sheet/strip needing good surface and thickness tolerance; strength raised by rolling, ductility reduced. Yield strength is 260 MPa in HR versus 460 MPa in CR.
Can FabDigit make parts in 1030 Q&T-425?
Yes — 1030 Q&T-425 is available for CNC machining and sheet metal with instant online pricing. Upload a STEP file to get a price and a DFM check.
Sources
- SAE J403 — Chemical Compositions of SAE Carbon Steels — SAE International (2014)
- ASTM A29/A29M — Steel Bars, Carbon and Alloy, Hot-Wrought, General Requirements — 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 (carbon steel mechanical property tables) — ASM International (1990)
- ASM Handbook Vol.4 — Heat Treating (hardenability and tempering of 10xx steels) — ASM International (1991)
- JIS G 4051 — Carbon steels for machine structural use (S30C) — JSA (2016)
- EN 10083-2 / DIN 17200 — Non-alloy quality steels for quenching and tempering (C30, 1.0528) — CEN (2006)
- Mysteel / carbon structural bar price quotations — Mysteel, SMM (2025)
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.