Steel 45# Normalized
Heat-treated state
GB 45# · JIS S45C · BS En45
Standard GB/T 699 delivery condition for bars and forgings: uniform fine pearlite, good toughness, meets Rm ≥ 600 MPa / Rel ≥ 355 MPa.
Values for the Normalized condition
Other 45# tempers and conditions
45# is listed in 8 conditions; see the grade overview at 45#.
Compare all 8 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
Hot rolled | Cheapest form for weldments and parts that will be heat treated or fully machined afterwards. | 330 | 580 | 18 | 170 HB | — |
Solution annealed | Softest condition — pick for heavy cold forming, deep boring or maximum dimensional stability before final heat treat. | 340 | 570 | 22 | 163 HB | — |
NormalizedThis page 840–870 °C, air cooled | Standard GB/T 699 delivery condition for bars and forgings: uniform fine pearlite, good toughness, meets Rm ≥ 600 MPa / Rel ≥ 355 MPa. | 375 | 630 | 18 | 179 HB | — |
CDDefault Cold drawn | Most stocked condition for shafts and turned parts: tight tolerance, bright surface, ~530 MPa yield without heat treatment. | 530 | 625 | 12 | 179 HB | — |
Quenched (water/oil 820–860 °C) + high temper 560–620 °C | The classic quench-and-temper condition — water or oil quenched from 820–860 °C, tempered at 560–620 °C — for gears, shafts and couplings; best strength/toughness compromise and still machinable. | 600 | 800 | 16 | 22 HRC | — |
Induction hardened | Pick for wear surfaces — journals, spline flanks, guide rails — where a hard case plus tough core is needed. | 600 | 800 | 14 | 57 HRC | — |
Quench + temper ~500–540 °C | Use the higher-strength quench and temper (~500–540 °C) for keyed shafts, spindles and pins needing 780 MPa yield and some wear resistance, at reduced machinability and weldability. | 780 | 950 | 14 | 30 HRC | — |
Quench + temper ~420–480 °C | Maximum practical through-hardened strength for 45# in sections under ~40 mm; toughness starts to drop. | 900 | 1,100 | 11 | 35 HRC | — |
What is 45# Normalized?
45# Normalized is 45# heat treated to Normalized — standard GB/T 699 delivery condition for bars and forgings: uniform fine pearlite, good toughness, meets Rm ≥ 600 MPa / Rel ≥ 355 MPa. 45# Normalized has a yield strength of 375 MPa (54.4 ksi) and a tensile strength of 630 MPa (91.4 ksi) — weaker than 70% of steel grades. Elongation at break is 18% and the elastic modulus is 205 GPa (29.7 Msi). 45# Normalized 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; Normalized is available on request or by drawing note.
Advantages
- High electrical conductivity — 10.8 % IACS, better than 94% of steel grades
- Conducts heat well — 49 W/m·K (28.3 BTU/hr·ft·°F), better than 83% of steel grades
Limitations
- Low fracture toughness — 62 MPa·√m (56.4 ksi·√in), worse than 76% of steel grades
45# Normalized properties
Typical room-temperature values for 45# Normalized; 14 are specific to this condition. Other listed values are 45# reference data and may not represent this condition. Bars are the position among steel grades.
Physical3
45# Normalized 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
45# Normalized has a yield strength of 375 MPa (54.4 ksi) and a tensile strength of 630 MPa (91.4 ksi) — weaker than 70% of steel grades. Elongation at break is 18% and the elastic modulus is 205 GPa (29.7 Msi).
Thermal6
45# Normalized is rated for continuous service to 425°C (797 °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
45# Normalized conducts electricity at 10.8 % IACS, better than 94% of steel grades.
Chemical & Environmental3
Corrosion resistance is not recommended (10/100), worse than 86% of steel grades.
Sustainability4
Producing a kilogram of 45# Normalized takes about 25 MJ of energy and emits 2 kg of CO₂ — less than 82% of steel grades. Typical recycled content is 25%.
Manufacturability7
45# Normalized's machinability is good (56/100, better than 71% of steel grades); weldability fair (46/100); formability fair (38/100).
Values are nominal handbook figures for design screening. Confirm any required mill or lot documentation when quoting.
Working with 45# Normalized
Is 45# easy to machine?
Good general machinability at 57 % of 1212; turn normalized/CD material at 120–180 m/min with coated carbide, keep hardness ≤255 HB for tapping and expect built-up edge on annealed stock.
Can 45# be welded?
Weldable with care only — CE ≈ 0.6, so preheat 150–250 °C, use low-hydrogen E7018/ER70S-6 and post-weld temper at 600 °C to avoid HAZ martensite and cracking.
Can 45# be formed, bent or molded?
Hot forge 850–1200 °C then normalize; cold bending is limited (min bend radius ≈ 2–3 t) and should be done in the annealed condition.
What surface finishes work on 45#?
No anodizing; protect with black oxide, phosphate + oil, zinc or hard-chrome plating, nitriding for wear, or primer/paint — bare surfaces rust within days in humid air.
45# 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/T 699 grade 45 | 0.42 – 0.5 | 0.45 |
| Si | 0.17 – 0.37 | 0.27 |
| Mn | 0.5 – 0.8 | 0.65 |
| P | ≤ 0.04 | 0.02 |
| S | ≤ 0.04 | 0.02 |
| Crresidual | ≤ 0.25 | 0.1 |
| Niresidual | ≤ 0.3 | 0.1 |
| Curesidual | ≤ 0.25 | 0.1 |
| Fe | balance |
45# Normalized — frequently asked
What is 45# Normalized used for?
45# Normalized is typically used for crankshafts, shafts and industrial bolts. In short: workhorse medium-carbon plate.
What is the yield strength of 45# Normalized?
45# Normalized has a typical yield strength of 375 MPa (54.4 ksi) and a tensile strength of 630 MPa (91.4 ksi) — weaker than 70% of steel grades. Strength varies by condition: see the 8 listed tempers.
Is 45# Normalized easy to machine?
Reasonably — machinability is rated good (56/100, better than 71% of steel grades). Good general machinability at 57 % of 1212; turn normalized/CD material at 120–180 m/min with coated carbide, keep hardness ≤255 HB for tapping and expect built-up edge on annealed stock.
Can 45# Normalized be welded?
With care — weldability is rated fair (46/100). Weldable with care only — CE ≈ 0.6, so preheat 150–250 °C, use low-hydrogen E7018/ER70S-6 and post-weld temper at 600 °C to avoid HAZ martensite and cracking.
What surface finishes work on 45# Normalized?
No anodizing; protect with black oxide, phosphate + oil, zinc or hard-chrome plating, nitriding for wear, or primer/paint — bare surfaces rust within days in humid air.
Can 45# Normalized be formed, bent or molded?
Hot forge 850–1200 °C then normalize; cold bending is limited (min bend radius ≈ 2–3 t) and should be done in the annealed condition.
What is the maximum service temperature of 45# Normalized?
45# Normalized is rated for continuous use to about 425°C (797 °F). Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
What is the difference between 45#-CD and 45#-HR?
CD is the default condition — most stocked condition for shafts and turned parts: tight tolerance, bright surface, ~530 MPa yield without heat treatment. HR: cheapest form for weldments and parts that will be heat treated or fully machined afterwards. Yield strength is 530 MPa in CD versus 330 MPa in HR.
Can FabDigit make parts in 45# Normalized?
Yes — 45# Normalized 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
- GB/T 699 (Quality carbon structural steels) — SAC (2015)
- JIS G 4051 (S45C) / EN 10083-2 (C45) — JISC / CEN (2016)
- ASM Handbook Vol. 1: Properties and Selection — Irons, Steels — ASM International (1990)
- ASM Handbook Vol. 4: Heat Treating (carbon steel Q&T data) — ASM International (1991)
- ASM Handbook Vol. 16: Machining (machinability ratings) — ASM International (1989)
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.