PMTLee Vaccum Technologies PVT Ltd

Why Heat Treatment ?

To Increase/decrease Hardness, Strength ( Tensile and Proof ) and mechanical properties (Elongation, Reduction in area, Impact strength)
For Grain refinement, Transformation of products, Homogeneity of phases
To Stress relieve and remove work hardening effect
To Dissolve alloy constituents ( solutionizing) and aid in precipitation hardening thereby increasing hardness
To Improve corrosion resistance and wear resistance.
To Retain the shape for a long time
To Improve electrical conductivity
Reduce Brittleness and improve Toughness, Ductility, Malleability, Formability and Bending properties

Purpose of Heat Treatment

Relieve stresses after either hot or cold working
Improve ductility and shock resistance
Modify electrical and magnetic properties
Harden tools, dies etc.
Change the grain size
Increase resistance to heat and corrosion
Harden the surface by Change of chemical composition( as in Carburizing, Nitriding, carbonitriding tuffriding etc )
Fully stress relieve, Spheroidising and malleabilizing
Harden surface without change in chemistry ( Induction , Flame hardening )

Our Service

Vacuum Heat Treatment

A common use of a vacuum furnace is heat treatment of steel and alloys. Many general heat treating applications involve the hardening and tempering of a steel part to make it strong and tough through service. Hardening involves heating the steel to a pre-determined temperature, then cooling it rapidly.

Vacuum furnaces are ideal for brazing applications. Brazing is another heat-treating process used to join two or more base metal components by melting a thin layer of filler metal in the space between them.

What is Vacuum?

A rare fraction of molecule is called vacuum.

Atmospheric pressure is variable but standardized at 101.325 kPa (760 Torr)
Low vacuum, also called rough vacuum or coarse vacuum, is vacuum that can be achieved or measured with rudimentary equipment such as a vacuum cleaner and a liquid column manometer.
Medium vacuum is vacuum that can be achieved with a single pump, but the pressure is too low to measure with a liquid or mechanical manometer. It can be measured with a McLeod gauge, thermal gauge or a capacitive gauge.
High vacuum usually requires multi-stage pumping and ion gauge measurement.
Ultra high vacuum requires baking the chamber to remove trace gases, and other special procedures. British and German standards define ultra high vacuum as pressures below 10-6 Pa (10-8 Torr).

What are the materials Heat Treated in Vacuum Furnace?

High Speed Tool Steels - M2, M35, M42, T42, T2, Vanadis, SKH51 & ASP Grades, S390, S600 etc.s
Cold Work Tool Steel - D2, D6, A2, K110, SLD, Swerker 21, SKD11,SKD21, SV3 etc.
Hot Die Steels - H10A, H11, H12, H13, Orvar Supreme, Dievar, Dac10, Eskylos 2083, Eskylos 2738, W300, W302, W360, SKD SERIES, DAC SERIES, HP SERIES, STAVAX, CALMAX etc.
Stainless/ Plastic Mould Steels - SS420, SS440 C,Pptn. Hardening St. Steels, M300, P20, HPM Series, NIMAX etc.

Ultrasonic Cleaning

We take pride in the fact that we are the pioneers in introducing Ultrasonic Cleaning in today's fast changing technology and which is essential for an effective and scientific cleaning of the job prior to vacuum heat treatment & which is possible only with this technology thereby ensuring better heat treatment results.

What is Ultrasonic Cleaning ?

An ultrasonic cleaner is a cleaning device that uses ultrasound (usually from 20-400 kHz) and an appropriate cleaning solvent (sometimes ordinary tap water) to clean delicate items. The ultrasound can be used with just water, but use of a solvent appropriate for the soiling and the item to be cleaned enhances the effect. Cleaning normally lasts between three to six minutes, but can also exceed 20 minutes, depending on the cleanliness of the object.
Ultrasonic cleaners are used to clean many different types of objects like jewellers, lenses and other optical parts, watches, dental and surgical instruments, tools & dies, coins, fountain pens, golf clubs, window blinds, firearms, musical instruments and electronic equipment, industrial parts to remove corrosion, oxidation effects, deposition of foreign material (oil, grease, lapping paste). They are useful in vacuum heat treatment, plasma nitriding many jewellery workshops, watchmakers' establishments, and electronic repair workshops.

Cryogenic Treatment (Sub-Zero Quenching):

To convert and minimize the retained austenite and to gain full martensitic structure, for good strength and better mechanical properties this treatment is very much important and is to be followed immediately after Quenching. Our sub zero chamber is capable of attaining -1200C.

The correct term is 'cryogenic treatment', not cryogenic quench. The steel is QUENCHED immediately after austenitizing and it is not quenched in liquid nitrogen. In general, cryogenic treatment is referred to as 'cryogenic tempering' since it does transform retained austenite. Some professional heat treating services refer to it as that. It is wrong to refer to it as temper since it DOES NOT temper the martensite. The retained austenite transformed to martensite by cryogenics is NOT tempered and all usual tempering should be performed after the treatment. The first tempering should be performed immediately upon the steel warming to room temperature. To do it properly the steel should immediately be placed into cryo upon reaching room temperature for high alloy steels after a snap temper (which is performed immediately after the steel reaches approximately, but no less than, 125 F after quench). The snap tempering after quench is a preference of some and others skip the snap temper for high alloy steels and go straight to cryo immediately after the steel cools enough after quench.
The thing to remember about cryogenic treatment is: It will transform retained austenite into un tempered martensite. That is ALL it does. This un tempered martensite must be tempered, therefore all tempers except for a previous snap temper are performed after the cryogenic treatment.

Advantages of Cryogenic Treatment (Sub-Zero Quenching)

Reduces friction and wear properties as well as surface roughness
Alters and refines the molecular grain structure
Allows the machining of parts to tighter tolerances
Increases dimensional stability on critical components
Relieves stress fracturing
Provides for easier machining and redressing
Increases component durability and lifespan
Lowers replacement costs and downtime due to increased wear resistance

Vacuum Tempering

We have the Tempering Furnace with facility of not only Vacuum level of 10^-1 m bar but also protective atmosphere of Nitrogen.

Also temperature-sensitive silicone rubber parts can be tempered (Tempering with 100°C!)
The vacuum process has an additional degree of freedom for process optimization.
It retains the advantages of vacuum hardening in terms of cleaner surface with low oxidation and decarburization effects thereby reducing the finish cleaning operations.
Heat exhaust" quantity is significantly reduced which means low emissions.
Very low contaminated industrial effluent
Only minimal odour problems (peroxides)

Multiple Facilities Under One Roof

Also temperature-sensitive silicone rubber parts can be tempered (Tempering with 100°C!)
The vacuum process has an additional degree of freedom for process optimization.
It retains the advantages of vacuum hardening in terms of cleaner surface with low oxidation and decarburization effects thereby reducing the finish cleaning operations.
Heat exhaust" quantity is significantly reduced which means low emissions.
Very low contaminated industrial effluent
Only minimal odour problems (peroxides)