Characteristics, Heat Treatment, and Equivalents
S45C, also known by several equivalents such as AISI 1045, 1191, EN9, and C45, is a medium tensile, low hardenability carbon steel. It is commonly supplied in a cold-drawn or turned and polished condition, featuring a tensile strength range of 600 to 950 MPa and a Brinell hardness range of 179 to 280. This steel grade is characterized by its good strength, impact resistance, and reasonable weldability, making it a versatile choice for a variety of industrial applications.
Characteristics and Machinability S45C steel, along with its equivalents such as 1045, 1191, and EN9, is known for its excellent machinability in the cold-drawn or turned and polished condition. Operations like turning, drilling, broaching, milling, and tapping can be carried out efficiently, provided that the machine manufacturer’s recommendations for tooling, feeds, and speeds are followed. This steel is widely used in applications where enhanced strength and wear resistance are required but where the higher strength of low alloy high tensile steels is not necessary.
| DIN | AISI | JIS | S45c Chemical Composition | |||||||||||
| C | Si | Mn | P | S | Co | Cr | Mo | Ni | V | W | Cu | |||
| CK45 | 1045 | S45C | 0.42 to 0.48 | 0.20 to 0.35 | 0.60 to 0.90 | ≤ 0.030 | ≤ 0.035 | – | – | – | – | – | – | – |
S45c equivalent material
| Country | USA | British | Japan | Australia | |||||
| Standard | ASTM A29 | EN 10083-2 | JIS G4051 | AS 1442 | |||||
| Grades | 1045 | C45/1.1191 | S45C | 1045 | |||||
What is the typical ultimate tensile strength for Jls S45C?
| Tensile | Yield | Elongation | Hardness | |
| Strength | Strength | In 50mm | Brinell | |
| Mpa | Mpa | % | HB | |
| 570 – 700 | 300 – 450 | 14 – 30 | 170 – 210 | |
S45c Mechanical Properties -Normalised Condition
| Yield | Elongation | Impact | Hardness | ||||
| Tensile | Strength | in 50mm | Izod | ||||
| Strength | Mpa | % | J | ||||
| Mpa | HB | Rc | |||||
| 640 | 410 | 22 | 54 | 187 | 10 | ||
Heat Treatment Processes
Annealing
For annealing S45C steel, the material should be heated to 800°C – 850°C and held until the temperature is uniform throughout the section, followed by cooling in the furnace. This process softens the steel, improving its machinability and relieving internal stresses.
Flame or Induction Hardening
S45C can be effectively flame or induction hardened in its supplied condition. The material is heated rapidly to the austenitic temperature range of 820°C – 860°C, depending on the desired case depth, followed by immediate quenching in water or oil. The resulting surface hardness can reach Rc 54 – Rc 60, while the core strength remains unchanged. To relieve quenching stresses in the case, most components should be tempered at 150°C – 200°C immediately after quenching. This tempering has minimal impact on the surface hardness.
Hardening
For through hardening, S45C should be heated to 820°C – 850°C, held until the temperature is uniform, and soaked for 10 – 15 minutes per 25mm of section thickness before quenching in water or brine. Alternatively, it can be heated to 830°C – 860°C and quenched in oil, followed by immediate tempering while the material is still hand-warm.
Normalizing
To normalize S45C steel, it should be heated to 870°C – 920°C, held until the temperature is consistent throughout the section, soaked for 10 – 15 minutes, and then allowed to cool in still air. This process refines the grain structure, improving toughness.
Stress Relieving
Stress relieving is achieved by heating S45C to 550°C – 660°C, holding it until the temperature is uniform, soaking for 1 hour per 25mm of section thickness, and then cooling in still air. This process reduces residual stresses that could affect the material’s performance.
Tempering
To temper S45C steel, reheat the material to 400°C – 650°C as required, hold until the temperature is consistent throughout the section, soak for 1 hour per 25mm of section thickness, and cool in still air. Tempering adjusts the hardness and strength of the steel according to the requirements of the specific application.
S45C Steel Equivalents
S45C shares its properties with several equivalent steels, including AISI 1045, 1191, EN9, and C45. These equivalents are used interchangeably in various industries depending on regional standards and availability. Each of these steels shares similar mechanical properties, making them suitable for applications requiring moderate strength, toughness, and wear resistance, such as shafts, gears, bolts, and machinery parts.
S45C carbon steel and its equivalents are highly versatile materials suitable for a range of industrial applications. Their balanced combination of strength, machinability, and hardenability, coupled with the ability to undergo various heat treatment processes, makes them a reliable choice for manufacturing components that demand moderate wear resistance and durability.
