12 Popular Heat Treatment Combinations of Alloy Steels

Process Steps:

1. 1Austenitize at ~850°C (1560°F)
2. 2Oil or water quench to transform into martensite
3. 3Temper at 200–600°C (400–1100°F) to achieve desired toughness

Common Applications:

• Gears
• Crankshafts
• Drill collars
• Aerospace forgings

Process Steps:

1. 1Austenitize at ~830°C (1525°F)
2. 2Quench in a molten salt bath at ~300–400°C (570–750°F)
3. 3Hold to form bainite, then air cool

Common Applications:

• Landing gear
• Power transmission shafts
• Military armor components

Process Steps:

1. 1Surface heating by induction coils to 850–900°C
2. 2Rapid quench, producing a hard martensitic surface
3. 3Core remains tough and ductile

Common Applications:

• Automotive axles
• Shafts
• Agricultural equipment

Process Steps:

1. 1Austenitize at ~840°C (1540°F)
2. 2Oil quench to form hard martensite
3. 3Temper at 150–200°C for dimensional stability

Common Applications:

• Bearings
• Rolling elements
• Precision tools
• Machine components

Process Steps:

1. 1Carburize in carbon-rich furnace at 900–950°C
2. 2Quench to harden the surface (martensite)
3. 3Core remains tough and ductile

Common Applications:

• Gears
• Camshafts
• Fasteners
• Crankshafts

Process Steps:

1. 1Austenitize at ~1020°C (1870°F)
2. 2Gas quench in vacuum furnace
3. 3Multiple temper cycles at ~550°C (1020°F)

Common Applications:

• Die casting dies
• Hot forging tools
• Extrusion dies
• Molds

Process Steps:

1. 1Austenitize at ~790°C (1450°F)
2. 2Oil quench for uniform hardness
3. 3Temper at 150–250°C to relieve stress

Common Applications:

• Cutting tools
• Knives
• Stamping dies
• Gauges

Process Steps:

1. 1Austenitize at ~1020°C (1870°F)
2. 2Air or gas quench (air-hardening steel)
3. 3Temper at 200–500°C for required hardness

Common Applications:

• Shear blades
• Punches
• Molds
• High-performance cutting tools

Process Steps:

1. 1Heat to ~900°C (1650°F) for normalizing, then air cool for uniform grain refinement
2. 2Follow with tempering at 500–600°C (930–1110°F) for toughness

Common Applications:

• Aerospace components
• Roll cages
• Pipelines
• Pressure vessels

Process Steps:

1. 1Austenitize at ~870°C (1600°F)
2. 2Oil quench for martensitic hardness
3. 3Temper at 200–500°C depending on hardness vs. toughness requirements

Common Applications:

• Springs
• Torsion bars
• High-performance shafts
• Heavy-duty fasteners

Process Steps:

1. 1Carburize at 900–950°C to enrich surface carbon
2. 2Quench for a hard wear-resistant surface
3. 3Temper to achieve core toughness

Common Applications:

• Aircraft gears
• Transmission systems
• Aerospace drive shafts
• High-load bearings

Process Steps:

1. 1Austenitize at ~925°C (1700°F)
2. 2Air or gas quench (shock-resistant tool steel)
3. 3Double temper at 500–550°C to reduce retained austenite and improve toughness

Common Applications:

• Chisels
• Punches
• Hammers
• Shear blades
• Impact tools