Heat treatment

Leybold offers tried and tested vacuum technology for every heat treatment application.

Tecnologia del vuoto affidabile ed efficiente per ogni applicazione di trattamento termico

One of the drivers in vacuum furnaces is the ever-increasing demand for high-quality metal parts from the aerospace and automotive industries. These sectors demand modern components that are capable of meeting the highest standards. These standards can be achieved by heat treatment under vacuum.

Unexpected furnace downtime causes high production costs, as the production steps are designed according to the just-in-time model. The various heat treatment applications present different challenges for the vacuum systems used. Since 1850, our customers worldwide rely on our experience and expertise. Leybold offers tried and tested vacuum technology for every heat treatment application.

Heat treatment of workpieces is a known and well-proven technology. The purpose of heat treatment is to modify or influence the properties of a material in a controlled manner. The process cares for a higher quality of a base material. In times of diminishing raw materials resources and increasing pressure on costs, heat treatment technologies have worldwide a growing demand.

Utilizzo del vuoto per il trattamento termico

Influencing the properties of materials through a heat treatment is restricted when this treatment is done under normal atmosphere.

These limits are defined by:

Chemical reaction of the hot material surface with oxygen (oxidation) or other components of the surrounding air.
Inclusion of gas molecules from the surrounding gas into the material surface.

Through the use of an inert gas it is possible to prevent oxidation, however, the other potential influences remain. Only the complete removal of all gases out of the furnace atmosphere will prevent any reaction of the material with the ambient.

Ricottura

Tempering or annealing is typically used to “stress-relieve” a product after machining, welding or thermoforming. If a material is heated up to a high temperature and maintained there for a while, it can “balance” inner tension. After cooling down slowly, the parts are more stable against distortion.

Indurimento

Vacuum Hardening is an improvement over conventional hardening, as the component surfaces are protected from possible negative effects of exposure to a gaseous atmosphere. The vacuum treated material is quenched in gas or liquid, depending on the specification requirements. As result of a vacuum hardening, the material receives an extreme clean and shining surface.

Brasatura

Brazing is defined as a joining process that occurs at T > 400 °C and below the melting point of the base material. A filler material is melted and solidifies in a narrow space between the surfaces to be joined. Most of the common metals can be brazed. Nevertheless, various filler materials, brazing methods or procedures are used.

Nitrurazione

Vacuum nitriding diffuses nitrogen into the surface of a metal to create a case-hardened nitride surface. This method is used e.g. for machine parts, gears or tools when mechanical properties as hardness or corrosion resistance must be increased. During the process, atomic nitrogen is formed via a catalytic decomposition of ammonia (NH₃) on the hot metal surface of a work piece (2 NH₃ -> 2 N + 3 H₂) Typical process temperature is 525°C

Cementazione

Carburizing is used to harden the surface of a steel for wear protection reasons by an enrichment with carbon. Typical parts for carburizing are machine parts, motor parts or tools. The advantage of vacuum carburizing can be found in the uniformity of the carburizing. All surfaces of the treated materials can be reached and uniformly treated

Sinterizzazione

Sintered materials consist out of metal or ceramic powder, which are “baked” together at the surface to form a workpiece. Actually the “MIM” (Metal Injection Molding) process is booming, which does also include a sintering process. Typical sintered parts are aluminum wheels, cemented carbide tools, gears, ceramic parts.