Steel 1045 · temper
Steel 1045-A
Properties of the A condition, compared with the other 1045 tempers.
Softest, most ductile and most stable condition — choose for deep machining, cold forming or before hardening.
What is 1045-A?
1045-A is 1045 in the A temper — softest, most ductile and most stable condition — choose for deep machining, cold forming or before hardening. 1045-A has a yield strength of 310 MPa (45 ksi) and a tensile strength of 585 MPa (84.8 ksi) — weaker than 83% of steel grades. Elongation at break is 27% and the elastic modulus is 205 GPa (29.7 Msi). 1045-A has a density of 7.85 g/cm³ (0.284 lb/in³), heavier than 56% of steel grades. It melts at 1,420°C (2,588 °F). CD is the default condition FabDigit quotes; A is available on request or by drawing note.
Advantages
- High electrical conductivity — 10.8 % IACS, better than 94% of steel grades
- Ductile — tolerates forming and impact — 27%, better than 85% of steel grades
- Conducts heat well — 49 W/m·K (28.3 BTU/hr·ft·°F), better than 83% of steel grades
Limitations
- Low strength — 310 MPa (45 ksi), worse than 83% of steel grades
- Low fracture toughness — 60 MPa·√m (54.6 ksi·√in), worse than 79% of steel grades
1045-A properties
Typical room-temperature values for 1045-A — 12 properties are specific to this condition; the rest are grade-level values shared by every 1045 temper. Each bar shows where the value sits among the steel grades in FabDigit's library — further right is higher.
Physical3
1045-A has a density of 7.85 g/cm³ (0.284 lb/in³), heavier than 56% of steel grades. It melts at 1,420°C (2,588 °F).
Mechanical16
1045-A has a yield strength of 310 MPa (45 ksi) and a tensile strength of 585 MPa (84.8 ksi) — weaker than 83% of steel grades. Elongation at break is 27% and the elastic modulus is 205 GPa (29.7 Msi).
Thermal6
1045-A is rated for continuous service to 400°C (752 °F). It conducts heat at 49 W/m·K (28.3 BTU/hr·ft·°F), better than 83% of steel grades. Thermal expansion is 11.7 µm/m·K (6.5 µin/in·°F).
Electrical3
1045-A conducts electricity at 10.8 % IACS, better than 94% of steel grades.
Chemical & Environmental3
Corrosion resistance is not recommended (12/100), worse than 53% of steel grades.
Sustainability4
Producing a kilogram of 1045-A takes about 25 MJ of energy and emits 2 kg of CO₂ — less than 82% of steel grades. Typical recycled content is 35%.
Manufacturability8
1045-A's machinability is good (55/100, better than 62% of steel grades); weldability fair (45/100); formability good (55/100).
Values are nominal handbook figures for design screening. Certified mill or lot data ships with every FabDigit order on request.
Other 1045 tempers and conditions
1045 is also supplied in 10 other conditions. The full side-by-side table is on the 1045 overview.
- CDDefaultDefault stock condition for shafts, pins and machined parts needing straight, on-size bar with higher yield than hot rolled.530 MPa yield · 179 HB
- QT 205Maximum hardness/wear condition for thin sections, keys, wear plates and small tooling; brittle and only for sections under ~25 mm (water quench).1,300 MPa yield · 52 HRC
- QT 32-36HRCHigher-strength Q&T band for highly loaded shafts and studs; toughness and machinability start to drop noticeably.950 MPa yield · 34 HRC
- QT 28-32HRCMost common ordered Q&T hardness band for machine shafts, gear blanks and hydraulic components.800 MPa yield · 30 HRC
- QT 22-26HRCPick this quenched and tempered (~600 °C) 22–26 HRC condition for shafts, couplings and bolts where machinability and impact toughness matter more than peak strength.570 MPa yield · 24 HRC
- IHChoose when you need a hard wear surface with a tough unhardened core — shaft journals, cam surfaces, gear teeth, hydraulic rods.500 MPa yield · 57 HRC
- A+CD1045 bar softened by full/sub-critical annealing before cold drawing — lower strength and higher ductility than straight cold-drawn stock, with a bright, close-tolerance surface and good machined finish.460 MPa yield · 175 HB
- NUniform fine-pearlite structure with balanced strength and toughness; standard pre-condition for gear and shaft blanks and after forging.340 MPa yield · 179 HB
- HRCheapest form; pick for weldments, large sections and parts that will be fully machined or later heat treated.310 MPa yield · 163 HB
- ASoftest, most ductile and most stable condition — choose for deep machining, cold forming or before hardening.310 MPa yield · 163 HB
Working with 1045-A
Is 1045 easy to machine?
Machines predictably at ~55 % of 1212 in the 180–220 HB range; use rigid setups, coolant and sharp inserts, and prefer normalized or Q&T ≤32 HRC material for threading and drilling.
Can 1045 be welded?
Weldable with E7018/ER70S-6 but carbon ~0.45 % demands 150–260 °C preheat, low-hydrogen practice, slow cooling and often post-weld stress relief to avoid HAZ cracking.
Can 1045 be formed, bent or molded?
Hot forges easily at 1100–1200 °C; cold bending is limited (bend radii ≥2–3 t) and best done annealed or hot rolled rather than cold drawn.
What surface finishes work on 1045?
No anodizing; protect with paint, phosphate, black oxide, zinc or hard chrome plating — bare surfaces rust within days in humid air. Takes a good ground/polished finish, best when hardened.
1045 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 |
|---|---|---|
| CGB 45: 0.42–0.50; DIN C45: 0.42–0.50 | 0.43 – 0.5 | 0.45 |
| MnGB 45 / JIS S45C: 0.50–0.80 | 0.6 – 0.9 | 0.75 |
| Sinot specified in SAE 1045 bar; GB 45 = 0.17–0.37 | 0.15 – 0.35 | 0.25 |
| Pmax, ASTM A29 | ≤ 0.04 | 0.02 |
| Smax, ASTM A29 | ≤ 0.05 | 0.02 |
| Crresidual limit (GB/T 699) | ≤ 0.25 | — |
| Niresidual limit (GB/T 699) | ≤ 0.3 | — |
| Curesidual limit (GB/T 699) | ≤ 0.25 | — |
| Fe | balance | — |
1045-A — frequently asked
What is 1045-A used for?
1045-A is typically used for gears, axles and shafts. In short: high-strength shafting steel.
What is the yield strength of 1045-A?
1045-A has a typical yield strength of 310 MPa (45 ksi) and a tensile strength of 585 MPa (84.8 ksi) — weaker than 83% of steel grades. Strength varies by condition: see the 11 listed tempers.
Is 1045-A easy to machine?
Reasonably — machinability is rated good (55/100, better than 62% of steel grades). Machines predictably at ~55 % of 1212 in the 180–220 HB range; use rigid setups, coolant and sharp inserts, and prefer normalized or Q&T ≤32 HRC material for threading and drilling.
Can 1045-A be welded?
With care — weldability is rated fair (45/100). Weldable with E7018/ER70S-6 but carbon ~0.45 % demands 150–260 °C preheat, low-hydrogen practice, slow cooling and often post-weld stress relief to avoid HAZ cracking.
What surface finishes work on 1045-A?
No anodizing; protect with paint, phosphate, black oxide, zinc or hard chrome plating — bare surfaces rust within days in humid air. Takes a good ground/polished finish, best when hardened.
Can 1045-A be formed, bent or molded?
Hot forges easily at 1100–1200 °C; cold bending is limited (bend radii ≥2–3 t) and best done annealed or hot rolled rather than cold drawn.
What is the maximum service temperature of 1045-A?
1045-A 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 1045-CD and 1045-HR?
CD is the default condition — default stock condition for shafts, pins and machined parts needing straight, on-size bar with higher yield than hot rolled. HR: cheapest form; pick for weldments, large sections and parts that will be fully machined or later heat treated. Yield strength is 530 MPa in CD versus 310 MPa in HR.
Can FabDigit make parts in 1045-A?
Yes — 1045-A is available for CNC machining, sheet metal and casting & forging with instant online pricing. Upload a STEP file to get a price and a DFM check.
Sources
- ASTM A29/A29M Standard Specification for General Requirements for Steel Bars — ASTM (2020)
- ASTM A108 Standard Specification for Steel Bar, Carbon and Alloy, Cold-Finished — ASTM (2018)
- EN 10083-2 Steels for quenching and tempering — C45 / 1.0503 — CEN (2006)
- JIS G4051 Carbon steels for machine structural use (S45C) — JISC (2016)
- ASM Handbook Vol.1: Properties and Selection — Irons, Steels, and High-Performance Alloys — ASM International (1990)
- ASM Handbook Vol.16: Machining — ASM International (1989)
- ASM Handbook Vol.19: Fatigue and Fracture — ASM International (1996)
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.