Steel 1145 CD-SR
Heat-treated state
AISI/SAE 1145 · UNS G11450
CD-SR = cold drawn, stress relieved
Pick when unbalanced machining (keyways, deep slots) would otherwise bow the part after cutting.
Values for the CD-SR condition
Other 1145 tempers and conditions
1145 is listed in 9 conditions; see the grade overview at 1145.
Compare all 9 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
Solution annealed | Softest state for maximum dimensional stability, deep drilling and any limited cold forming or heading. | 310 | 570 | 22 | 163 HB | — |
Hot rolled | Cheapest form for large-diameter turned parts where the as-rolled surface will be machined away. | 325 | 585 | 18 | 170 HB | — |
Normalized | Uniform fine pearlitic structure before machining or hardening; better and more consistent properties than as-rolled. | 375 | 640 | 20 | 187 HB | — |
CD-SRThis page Cold drawn, stress relieved | Pick when unbalanced machining (keyways, deep slots) would otherwise bow the part after cutting. | 530 | 640 | 15 | 10 HRC | 10 % IACS |
Induction hardened | Use when only bearing or wear surfaces must be hard (55–60 HRC) while the core stays tough and machinable. | 560 | 700 | 12 | 57 HRC | 9 % IACS |
CDDefault Cold drawn | Default stocked condition: straight, size-accurate bright bar with raised strength and good chip control for CNC turning. | 565 | 655 | 12 | 187 HB | — |
quenched and tempered (high temper) | Tough general-purpose hardened condition for shafts and levers that still need drilling and tapping after heat treatment. | 690 | 830 | 17 | 24 HRC | — |
quenched and tempered (medium temper) | Most common hardened spec for medium-duty gears, spindles and hydraulic parts needing strength with some machinability. | 820 | 965 | 15 | 30 HRC | — |
quenched and tempered (low temper) | Highest practical through-hardened strength for this grade; accept reduced toughness and harder machining. | 950 | 1,100 | 12 | 34 HRC | — |
What is 1145 CD-SR?
1145 CD-SR is 1145 heat treated to CD-SR — pick when unbalanced machining (keyways, deep slots) would otherwise bow the part after cutting. 1145 CD-SR has a yield strength of 530 MPa (76.9 ksi) and a tensile strength of 640 MPa (92.8 ksi) — stronger than 69% of steel grades. Elongation at break is 15% and the elastic modulus is 205 GPa (29.7 Msi). 1145 CD-SR has a density of 7.85 g/cm³ (0.284 lb/in³), heavier than 56% of steel grades. It melts at 1,416°C (2,581 °F). CD is the default condition FabDigit quotes; CD-SR is available on request or by drawing note.
Advantages
- Easy to machine — 63/100, better than 92% of steel grades
- Conducts heat well — 49 W/m·K (28.3 BTU/hr·ft·°F), better than 83% of steel grades
- High electrical conductivity — 10 % IACS, better than 83% of steel grades
1145 CD-SR properties
Typical room-temperature values for 1145 CD-SR; 22 are specific to this condition. Other listed values are 1145 reference data and may not represent this condition. Bars are the position among steel grades.
Physical3
1145 CD-SR has a density of 7.85 g/cm³ (0.284 lb/in³), heavier than 56% of steel grades. It melts at 1,416°C (2,581 °F).
Mechanical13
1145 CD-SR has a yield strength of 530 MPa (76.9 ksi) and a tensile strength of 640 MPa (92.8 ksi) — stronger than 69% of steel grades. Elongation at break is 15% and the elastic modulus is 205 GPa (29.7 Msi).
Thermal6
1145 CD-SR is rated for continuous service to 370°C (698 °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
1145 CD-SR conducts electricity at 10 % IACS, better than 83% of steel grades.
Chemical & Environmental3
Corrosion resistance is not recommended (10/100), worse than 86% of steel grades.
Sustainability4
Producing a kilogram of 1145 CD-SR takes about 25 MJ of energy and emits 2 kg of CO₂ — less than 82% of steel grades. Typical recycled content is 30%.
Manufacturability7
1145 CD-SR's machinability is good (63/100, better than 92% of steel grades); weldability poor (30/100); formability poor (30/100).
Values are nominal handbook figures for design screening. Confirm any required mill or lot documentation when quoting.
Working with 1145 CD-SR
Is 1145 easy to machine?
Excellent turning/drilling at ~70 % of 1212 — run high surface speeds with sharp carbide, positive rake and good coolant; sulfides give clean chip break and fine finish.
Can 1145 be welded?
Avoid where possible: 0.45 %C plus 0.04–0.07 %S cause hot cracking and hard HAZ; if unavoidable preheat 200–300 °C, use low-hydrogen filler and post-weld stress relief.
Can 1145 be formed, bent or molded?
Only modest cold bending in annealed or hot-rolled condition; hot forge 1100–1230 °C and slow cool or normalize afterwards — do not cold form heavily in the cold-drawn state.
What surface finishes work on 1145?
No inherent corrosion protection — specify black oxide, phosphate + oil, zinc or hard chrome; sulfide stringers can leave micro-pits after polishing or plating.
1145 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/AISI 1145 per SAE J403 / ASTM A29 | 0.42 – 0.49 | 0.46 |
| Mn | 0.7 – 1 | 0.85 |
| P | ≤ 0.04 | 0.02 |
| Sresulfurized for machinability | 0.04 – 0.07 | 0.06 |
| Sinot specified for hot-rolled bar; 0.15–0.35 typical when ordered as killed steel | ≈ 0.22 | 0.22 |
| Fe | balance | — |
1145 CD-SR — frequently asked
What is 1145 CD-SR used for?
1145 CD-SR is typically used for shafts, axles and high-strength fasteners. In short: highest-carbon 11xx bar; between 1144 and 1146; strength over weldability.
What is the yield strength of 1145 CD-SR?
1145 CD-SR has a typical yield strength of 530 MPa (76.9 ksi) and a tensile strength of 640 MPa (92.8 ksi) — stronger than 69% of steel grades. Strength varies by condition: see the 9 listed tempers.
Is 1145 CD-SR easy to machine?
Reasonably — machinability is rated good (63/100, better than 92% of steel grades). Excellent turning/drilling at ~70 % of 1212 — run high surface speeds with sharp carbide, positive rake and good coolant; sulfides give clean chip break and fine finish.
Can 1145 CD-SR be welded?
Not readily — weldability is rated poor (30/100). Avoid where possible: 0.45 %C plus 0.04–0.07 %S cause hot cracking and hard HAZ; if unavoidable preheat 200–300 °C, use low-hydrogen filler and post-weld stress relief.
What surface finishes work on 1145 CD-SR?
No inherent corrosion protection — specify black oxide, phosphate + oil, zinc or hard chrome; sulfide stringers can leave micro-pits after polishing or plating.
Can 1145 CD-SR be formed, bent or molded?
Only modest cold bending in annealed or hot-rolled condition; hot forge 1100–1230 °C and slow cool or normalize afterwards — do not cold form heavily in the cold-drawn state.
What is the maximum service temperature of 1145 CD-SR?
1145 CD-SR is rated for continuous use to about 370°C (698 °F). Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
What is the difference between 1145-CD and 1145-A?
CD is the default condition — default stocked condition: straight, size-accurate bright bar with raised strength and good chip control for CNC turning. A: softest state for maximum dimensional stability, deep drilling and any limited cold forming or heading. Yield strength is 565 MPa in CD versus 310 MPa in A.
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 — ASM International (1990)
- ASM Handbook Vol.16 — Machining — ASM International (1989)
- GB/T 8731 — (free-cutting structural steel, Y45 comparison) — SAC (2008)
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.