In our company, atmosphere controlled batch type furnaces are used for the quench-temper process.
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We offer flexible charging opportunities to our customers with various furnaces with charging capacities of 600 - 1000 - 2000 kg.
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The origin of all of our 5 furnaces is Germany, and their brand is IPSEN, which is the world pioneer in its field.
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The Carb-o Prof program in our furnaces makes it possible to control parameters critical for the process - such as gas flow, temperature, protective atmosphere composition, oil temperature, cooling rate, etc. - and thus providing high reproducibility and traceability.
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Thanks to the Rapid-quench system, the materials cool faster and reach the possible maximum hardness value.
Since 1967, when our company was founded, we offer our customers the best quality with our state-of-the-art equipment and experience in quench & temper process which we have been carrying out for 50 years.
The Process In Onerler
What is Quench &Temper Process ?
Quench & temper is a method applied to give the required mechanical properties to steel. This Process increases the hardness, strength and toughness of the material.
This method basically consists of three steps.
In the first step, the material is heated until it reaches the austenite field by taking into account the iron carbon equilibrium diagram. After the steel is held at this temperature, its lattice structure changes and an austenitic structure is formed. This stage is carried out under shielding gas and in this way unwanted decarburization and oxidation to occur in the material at the high temperature are prevented.​
The steel whose lattice structure has changed moves from this step to the cooling phase, which is the second step. It is cooled rapidly by submerging in oil according to the cooling curve (TTT) diagrams according to the steel properties and desired hardness value. As a result of the cooling process, the steel structure turns into dense martensite from the austenite. As a result of the process, the material reaches the maximum hardness it can, but the material structure is subjected to intense stresses.​
After the cooling process, the material is quenched. In the last step, the material is reheated. Temperature and time parameters in the process vary according to the type of material, required hardness and material cross-section. As a result of the tempering process, the fragility of the material decreases and the stresses in the material are removed. Along with the tempering process, the hardness values of the steel decrease and the value of toughness increases.
Benefits of The Process
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High Wear Resistance
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High Strength
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High Fatigue Resistance
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High Hardness
- High Toughness
- High Impact Resistance
- High Stability
A steel with low hardness is processed easily and rapidly, and then subjected to quench & temper process to obtain the required strength and hardness.
This reduces the material and processing costs for the manufacturer, but also enables quick production.
It also prevents breakage of the cutting edge and cracking of materials during processing of a hard material.
Suitable Steels for The Process
Quench & temper process can be applied to almost all steels containing 0.3% or more carbon. In the following table, the steels used intensively in the market and tempered, and the maximum hardness values which they can gain after the tempering process are given in Rockwell.
Potential Problems After Process
One of the most troublesome problems in the process of quench & temper is the dimensional change in the materials. Quench & temper is a thermal process. The material is cooled rapidly after being heated at high temperatures, in this case the material naturally first expands and then shrinks rapidly, and when the material reaches the maximum possible hardness, stresses in the material also increase excessively. Even if the material is heated homogeneously, as a result of the shape of the material (especially thin and thick sections) and the processes carried out before heat treatment, inhomogeneous stresses in the material can cause increased dimensional change and even the material to crack.
After martensitic transformation in quench & temper, hardness is at the maximum level and internal stresses are at the highest level. If a steel in this state also contains residual stresses due to the processes prior to heat treatment, there may be more waste, or cracks may occur.
If a steel with high internal stresses is required to be tempered, in this case, the internal stresses of the steel should be removed by stress relief annealing. In spite of all this, if there is a high risk of waste or cracking in the material, vacuum hardening should be considered.
The manufacturer should correctly identify the cleaning criteria on the part surface prior to the process. Even if we use washing baths before and between the process in our company, quench & temper is a messier process compared to other processes due to its nature. After the process, stains can be seen on the surface of the material due to the effect of oil and temperature. If the situation is not in line with the cleaning criteria, methods such as vibration and surface cleaning may be applied after the process.
Heat Treatment
BOSB Turuncu Cad. No: 12, 16120
Nilüfer/Bursa, TURKEY
+90 (0224) 242 43 10
+90 (0224) 242 43 11 (fax)
Steel Supply
BeÅŸevler Sanayi Sitesi 26.Blok No: 6-15
Nilüfer/Bursa, TURKEY
+90 (0224) 441 97 13
+90 (0224) 441 46 15 (fax)