JIS G 4051 S45C steel plate standard

JIS G 4051 is the Japanese Industrial Standard that specifies the requirements for carbon steels used in the manufacture of machine parts, such as structural components and engineering parts that require good mechanical properties. The steel grades specified under JIS G 4051 are intended for use in general machine structural applications, and S45C is one of the most commonly used grades within this standard.

JIS G 4051 S45C Steel Plate:

S45C is a medium carbon steel with good tensile strength, hardness, and wear resistance. It is widely used in the production of machine parts such as shafts, gears, crankshafts, and other components that require good strength and toughness but are not exposed to extremely high-stress conditions.

Key Properties of S45C (JIS G 4051):
- Carbon Content: Approximately 0.45% carbon, which gives it moderate strength while still being relatively easy to machine and weld.
- Mechanical Properties:
- Yield Strength: Around 295 MPa (for hot-rolled material).
- Tensile Strength: Typically ranges between 540–700 MPa.
- Elongation: Around 16% (depends on the thickness of the material).
- Hardness: As hot-rolled material, it usually has a hardness of about 170-210 HB. After heat treatment (such as quenching and tempering), hardness can increase significantly.

Chemical Composition of S45C:
- Carbon (C): 0.42–0.48%
- Manganese (Mn): 0.60–0.90%
- Silicon (Si): 0.15–0.35%
- Phosphorus (P): ≤ 0.035%
- Sulfur (S): ≤ 0.035%
- Iron (Fe): The remainder, balanced with other elements.

Applications of S45C Steel:
- Machine Parts: S45C is commonly used for gears, shafts, axles, crankshafts, and connecting rods.
- Automotive Components: It is suitable for parts such as suspension components, brackets, and drive shafts.
- Construction: Structural components and machine parts that undergo moderate stress.
- Welding and Heat Treatment: S45C is relatively easy to weld and can be heat-treated to improve its mechanical properties. It can be quenched and tempered to achieve higher strength and hardness.

Heat Treatment of S45C:
S45C steel can be heat-treated to adjust its hardness and mechanical properties:
- Annealing: To make the steel more ductile and easier to machine, it can be annealed at temperatures around 850-900°C, followed by slow cooling.
- Hardening: By heating to 800-850°C and then quenching in water or oil, the steel can achieve higher hardness.
- Tempering: After hardening, tempering is done at temperatures between 150-650°C to achieve the desired balance of strength and toughness.

Surface Finish:
S45C steel can be produced with various surface finishes, including hot-rolled, cold-rolled, or machined depending on the application and required surface quality.

JIS G 4051 Standard Overview:
JIS G 4051 specifies the technical requirements for carbon steels used in manufacturing machine parts. It includes the following major aspects:
- Grade designations: Grades like S35C, S45C, S50C, S55C, etc., depending on the carbon content.
- Mechanical properties: Requirements for tensile strength, yield strength, elongation, etc.
- Chemical composition: The standard provides a strict composition range for each grade to ensure consistent mechanical properties.
- Testing: Steel products are tested for mechanical properties and compliance with the specified composition.

Summary:
JIS G 4051 S45C is a medium carbon steel with moderate tensile strength and good hardness. It is often used in machine parts and automotive components that require good strength and wear resistance. The steel is easy to machine, can be heat-treated for improved performance, and is suitable for use in a wide range of applications where moderate strength and toughness are required. It is a versatile material for engineering parts, with a balance between strength and ductility.