Vacuum Furnace Related Knowledge

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When treating the titanium alloy with a vacuum furnace, it is not preferable to use nitrogen as a cooling gas because titanium and nitrogen react at high temperature to form golden yellow titanium nitride.

The movable connection parts of the vacuum furnace are all sealed by O-rings and can be cooled by water.

When the workpiece is quenched under vacuum, vacuum quenching oil should be used, and the vacuum quenching oil has a lower saturated vapor pressure.

The maintenance of the vacuum furnace should be under vacuum or pure nitrogen, so as to avoid inhalation and moisture absorption when not in use.

During the heating process of the vacuum furnace, the workpiece and the material in the furnace will deflate, which will reduce the vacuum.

The heating temperature of vacuum tempering, vacuum annealing, vacuum solution treatment, and vacuum aging is generally the same as the heating temperature in the conventional treatment.

The vacuum tempering furnace should have a quick cooling device. The pressure of the cooling water should be greater than 0.2Mpa and the flow rate should be adjustable.

 

Vacuum furnace heating chamber type: graphite reflective screen and metal heat shield.

Vacuum furnace heating chamber selection:

Graphite reflective screen: Generally used in vacuum furnace, there are two kinds of hard felt and soft felt, which are suitable for quenching, tempering and annealing of general steel. High temperature brazing, powder metallurgy and sintering.

Metal heat shield: Generally used in vacuum furnaces are stainless steel and molybdenum. The molybdenum reflective screen is suitable for quenching, annealing, high temperature brazing, sintering, etc. of materials with high temperature and high requirements for the furnace environment (such as high temperature alloys, titanium alloys, magnetic materials, etc.). Stainless steel rice screen is suitable for tempering, low temperature annealing, aging, vacuum aluminum brazing, etc., some low temperature furnace type selection.

 

Vacuum selection:

Quenching heat treatment can be selected by medium vacuum (general ultimate vacuum 4X10-1Pa) using two-stage pump (front stage pump and Roots pump) such as bearing steel, die steel, structural steel and other vacuum heat treatment.

For some products requiring high vacuum, such as vacuum heat treatment or high temperature brazing of high temperature alloys, titanium alloys, magnetic materials, etc. Three-stage pumps (pre-stage pumps, Roots pumps, diffusion pumps, etc.) are generally required to have a vacuum degree. The ultimate vacuum is at 10-4Pa.