JIS G4051 S45C Carbon Steel Round Bar Medium Carbon Steel for Machine Structural Use

Material Overview

S45C is a medium-carbon steel grade specified under JIS G4051, intended for machine structural applications. With a carbon content of approximately 0.45%, it provides a balanced combination of strength, toughness, and machinability. It is commonly supplied as hot-rolled, normalized, annealed, or quenched-and-tempered round bar for various mechanical components.

Specifications

• Standard: JIS G4051 (Carbon steels for machine structural use)

• Common supply form: Round bar (also available as flats, squares, plates)

• Production methods: Hot rolling or hot forging

• Typical delivery conditions: Hot-rolled, normalized, annealed, or Q&T depending on requirements

• Size range: Manufacturer-dependent; widely available for shafts, pins, and mechanical parts

Key Characteristics

• Medium carbon content ensures high strength and good wear resistance

• Suitable for heat treatments including annealing, normalizing, quenching, and tempering

• Good machinability in normalized or annealed condition

• Suitable for moderately loaded parts requiring impact resistance

• Weldability is limited and requires preheating or post-heat due to higher carbon content

Our Advantages 

1. Chemical composition consistency
We guarantee full compliance with JIS G4051 chemical specifications for S45C. Every batch is accompanied by mill test certificates and full traceability to ensure stable composition.

2. Reliable mechanical properties
We supply S45C with verified mechanical performance. Typical ranges include tensile strength of 570–700 MPa and yield strength around 330 MPa in the normalized condition. Mechanical tests (tensile, hardness, impact) can be provided on request.

3. Excellent processing support
We offer S45C in optimal conditions for machining and provide heat-treatment guidance for applications requiring higher surface hardness. Customized services such as cutting, machining, hardening, and tempering are available.

4. Suitability for structural machine components
S45C is widely used for shafts, connecting elements, gears, and load-bearing parts. We help customers select the proper condition (normalized, annealed, Q&T) to match performance and service life requirements.

Chemical Composition

Mechanical Properties (Representative Values)

Standards

• Primary standard: JIS G4051 – Carbon steels for machine structural use

• Common equivalency references:

  • DIN/EN: C45 / CK45

  • AISI/SAE: 1045

  • EN 10083 structural steel family

Application Fields

General application range

S45C is used for machine components requiring moderate to high strength, good machinability, and optional heat treatment for increased hardness.

Typical applications

• Shafts and axles: Drive shafts, spindles, crankshafts

• Pins, studs, and keys: Locking pins, studs, bolts, key bars

• Gears and rollers: Hardness-treated gears, rollers, and wear parts

• Machine tool components: Holders, fixtures, forged parts

• Automotive and hydraulic components: Piston rods, cylinder rods, connecting parts

Q: Are you trading company or manufacturer ?

A: manufacturer,also can do trading.

Q: How long is your delivery time?

A: Generally speaking,it is 10-15 days if the goods are in stock,or it is 30-40 days if the goods are not in stock,

it is according to quantity.

Q: Do you provide samples? is it free or extra ?

A: Yes, we could offer the sample for free charge but need pay the cost of freight.

Q: What is your terms of payment ?

A: Payment<=2000USD, 100% in advance. Payment>=2000USD, 30% T/T in advance ,balance before shippment.

If you have another question, pls feel free to contact with me.