Vacuum Hardening

Vacuum hardening is a bulk heat treatment process performed under vacuum conditions, characterized by heating followed by rapid cooling using pressurized nitrogen gas. This process modifies the internal structure of the steel, increasing its hardness and wear resistance.

When hardening is followed by a subsequent tempering treatment, the process is referred to as quench and tempering, and it allows achieving an optimal balance between hardness and toughness, improving the mechanical performance of the component.

The treatment is particularly suitable for tool steels, stainless steels, high-speed steels, and special steels.

CHARACTERISTICS

Type of treatment:

Bulk heat treatment

Surface condition:

The process is clean as it is carried out under vacuum conditions and quenching is performed using nitrogen gas. The result is a component free from surface scale and oxidation.

Process description:

The steel is heated in a vacuum furnace to temperatures above 1000°C through radiation heating. The subsequent rapid cooling using pressurized inert gas (up to 10 bar) generates martensite, locking carbon atoms within the lattice and resulting in increased hardness and mechanical strength.

ADVANTAGES

• High core hardness

• Uniform mechanical properties

• Reduced surface oxidation

• Process repeatability

• Elimination of surface decarburization

• High toughness after tempering 

PROCESSABLE MATERIALS 

• high-alloy steels

• high-speed steels (HSS)

• tool steels

• martensitic stainless steels

• duplex stainless steels

EQUIPMENT

Total number of furnaces: 2

• No. 1 vacuum furnace: 700 mm x 600 mm x 1100 mm

• No. 1 vacuum furnace: 900 mm x 900 mm x 1200 mm

Operating temperature range: from 500 to 1300°C

Vacuum level: 10⁻³

Maximum quenching pressure: 10 bar

Quenching medium: nitrogen

APPLICATION EXAMPLES

Industrial 

• end mills and twist drills in S600
• tooling for stamping in steels 1.2379, 1.2343, 1.2083, 1.2344

Textile

• cutting blades and components in AISI 420