Vacuum Processing

HTA has Vacuum furnace processing facilities at its Brisbane and Melbourne branches. We currently have three furnaces on which have a large load carrying capacity and operating temperatures of up to 1220 C. Our largest furnace has the capacity for positive quenching in the pressure range up to 15 Bar which allows for the successful treatment of high speed steels through to lower grade alloy tool steels.

The vacuum process allows for the treatment of steels without surface oxidisation. This leaves the surface of the material free from flaking or discolouration and therefore reduces the finishing time of the material after heat treatment. Most steels which can be Vacuum treated have lower distortion levels than conventional oil hardened tool steels which makes finish machining easier.

  • Uniform temperatures in the range 800c �1200c
  • Temperature can be controlled within a small area
  • Low contamination of the product
  • Quick cooling ( quenching )
  • The process can be computer controlled to ensure metallurgical repeatability.

Heating metals to high temperatures normally causes rapid oxidization which is undesirable. A vacuum furnace removes the oxygen and prevents this from happening.

Many steels can be processed using Vacuum technologies which are available at Heat Treatment Australia. These include:

  • Plastic mould steels
  • Cold work steels
  • Hot work steels
  • High speed steels
  • Stainless Steels
  • PH / CRES Steels
  • Tool Steels.

Heat Treatment Australia has an extensive library of technical literature from tool steel manufactures to enable the correct processing and the maximum obtainable properties from each type of steel.

  • The size and shape of items that can be vacuum processed depends on the type of equipment operated by the heat treater. For large items, check the availability of suitably-sized facilities at an early stage.
  • Some steels and processes require special gas quenching methods , please consult with your heat treater whether this capability is available.


Typically component design with multi section thicknesses and available jigging can lead to undesired distortion usually not associated with Vacuum Processing.

Check with your heat treater to discuss options of jigging and stress relieving after rough machining and prior to pre hardening machining tolerances to aid in reducing distortion.

    All of the following information should be included if possible. If uncertain, ask your heat treater before producing a specification:

  • The process of vacuum hardening and number of tempers .
  • Material: type, grade, and the standard from which it is drawn, with drawing, composition and mill certificate where available.
  • Any general standards applicable (national, international or company) that contain relevant details which must be adhered to.
  • Existing condition; e.g. details of any prior heat treatment, such as hardening and tempering, solution treatment and ageing, intended to establish mechanical or other properties.
  • The level of mechanical properties required. Generally a hardness range . A maximum hardness level is often requested.
  • The type(s) of testing required; e.g. hardness (Vickers, Brinell), tensile etc. and any special locations for testing or the removal of samples for test pieces.
  • Requirements for any special certificates or data to be provided by your heat treater.

Guidance and information is always available from our experience heat treatment professionals.

Our procedures and work instructions are fully documented under our AS 9100 and ISO 9001 quality management systems.