Annealing, aging and oxidation

Main heat treatments

Stress relief annealing

A heat treatment to eliminate residual internal stresses.

Applicazioni
Components used in plastic deformation: intensive machining, welding, cold forming, forging, or quenching, and general applications where dimensional tolerances are required. This heat treatment is usually performed on both annealed and quenched and tempered steels.

Purpose
Reduction of internal stresses resulting from severe mechanical machining, both chip removal and electrical discharge machining.

Technical Specifications
Mechanical components are heated below the Ac1 temperature, between 450°C and 650°C, with a specific heating and cooling segment.

Softening annealing

A high-temperature heat treatment to ensure a uniform and fine-grained microstructure with low hardness.

Applications
Mechanical components before severe machining, castings, forged or hot-stamped parts.

Purpose
Improving machinability and imparting good isotropy to the steel microstructure.

Aging

A hardening process through the precipitation of solutes in the metal structure.

Applications
Precipitation-hardened stainless steels are classified into low-carbon martensitic (7-4 PH), semi-austenitic (17-7 PH), and austenitic (A-286). Precipitation hardening can also be achieved with non-ferrous alloys such as aluminum, magnesium alloys, etc.

Purpose
Massive treatment (to the core) to enhance mechanical properties and corrosion resistance with less deformation compared to traditional heat treatments.

Technical Specifications
The material to be aged must be solution-treated. The material is heated to an appropriate temperature to form precipitates and held for a specific time, after which it is cooled sufficiently rapidly to prevent the precipitation of carbides or intermetallic phases along the grain boundaries.

Oxidation

Processo termochimico per la formazione di uno strato superficiale ossidato controllato.

Applications
Automotive components, particularly frames, brakes, transmissions, and engine components, exposed hydraulic parts, parts used in die-casting in contact with molten metal. Often performed after nitriding/nitrocarburizing.

Purpose
Improvement of sliding properties. Enhancement of wear resistance and corrosion resistance, especially in combination with a nitride compound layer. This treatment is dimensionally stable and provides an excellent surface finish.

Technical Specifications
Oxidation process at a temperature between 400°C and 500°C to form a thin layer of black oxides up to 5 µm thick on the nitrided surface.