under reduced pressure or vacuum

Full Title

General methods or devices for heat treatment, e.g. annealing, hardening, quenching or tempering > Methods of treatment in inert gas, controlled atmosphere, vacuum or pulverulent material > under reduced pressure or vacuum

Classification Context

Section:

CHEMISTRY; METALLURGY

Class:

METALLURGY OF IRON

Subclass:

MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING