1045 - Medium Carbon Steel

Hardness & Properties

Hardness (annealed): ~180-230 HB (Brinell)

Hardness (heat treated): Up to ~55 HRC (Rockwell C)

Carbon Content: 0.43-0.50%

Material Type: Medium Carbon Steel

Typical Thickness Range: 6mm - 100mm

Properties

• Moderate wear resistance in annealed condition
• Improves significantly after heat treatment - Induction/flame hardening
• Good machinability - Easier to machine than alloy steels
• Excellent weldability - With proper procedures
• Cost-effective - Lower cost than alloy steels

Applications

• Machinery wear strips
• Drive plates and gears
• Sliding surfaces
• Shafts and axles
• Couplings and sprockets
• Wear pads
• General machinery components
• Light-duty wear applications

Heat Treatment Options

Normalizing: Heated to 870-900°C, air cooled. Improves machinability and grain structure.

Annealing: Heated to 790-815°C, furnace cooled. Softens material for machining.

Quenching & Tempering: Quenched from 820-850°C in water or oil, then tempered at 540-650°C. Achieves hardness up to 55 HRC.

Induction/Flame Hardening: Surface hardening technique that hardens only the surface while maintaining tough core.

Advantages

• Versatile - Can be used in multiple conditions (annealed, normalized, hardened)
• Good machinability - Easier to machine than higher carbon or alloy steels
• Heat treatable - Can be hardened for improved wear resistance
• Cost-effective - Lower material cost than specialty steels
• Widely available - Common grade with good availability

Processing Characteristics

Cutting: Can be cut using standard methods. Easier to cut in annealed condition.

Forming: Good formability in annealed condition. Should be heat treated after forming if hardness is required.

Welding: Good weldability. Preheat recommended for thick sections. Use low-hydrogen electrodes.

Machining: Good machinability in annealed or normalized condition. More difficult after hardening.

Comparison with Other Grades

vs. 1018: 1045 offers higher strength and better wear resistance after heat treatment.

vs. 4140: 4140 provides better hardenability and toughness but at higher cost.

vs. AR400: AR400 offers superior wear resistance but 1045 is more machinable and cost-effective.

Best for: Light to moderate wear applications where cost-effectiveness and machinability are important, especially when surface hardening can be applied.