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COLD WORK-HOT WORK TOOL STEEL HEAT TREATMENT

 

HEAT TREATMENT
To achieve the expected properties of the tool steel , the steel must be subjected to hardening treatment after processing . As a result of the hardening steels in the catalogs specified hardness, toughness , wear resistance have properties such as corrosion resistance .

I usually lasting for annealed steel is delivered to the user . Mold until it is used or the team passed through the following stages :

Roughing process ( pre-treatment )
Stress relief annealing
Last chip process ( grinding to share )
preheating
Keep in the heat hardening ( austenitizing )
quenching
Stabilization ( balancing, mapping)
Menevişleş the
cementation
Heat to a better understanding of the process of hardening gereklidir.aşağı know what happened , as shown in the figure , the quenching process is the process of actually changing the structure of the steel output . Substituted by quenching made ​​of austenitic steel, martensitic or bainitic structure at the end of quenching is achieved .

 

To summarize the events seen :
· Steel, started to be heated for quenching , the body-centered cubic structure consists of the unit mesh . There is no carbon atoms in the cage .

· 700 º C ? When it comes to temperatures above , KHM ? Line cells face-centered cubic lattice temperature effect gradually begins to take form .

· Ostenizasyo temperature is reached , only the structure of the steel KYM ary cages formed. To enter into the cage of carbon atoms, the space was born .

· Sudden quenching with carbon atoms having sufficient time to escape because t- is trapped in a cage . Because of the inherent carbon atoms in a cage is a very tense situation ( before tempering state). Soğutuls was slow , the atoms would have time to escape . Would not harden .

· Menevişleş stresses will be resolved in a cage on the stage . Revealed a structure more compatible with each other .

 

Water supply : all steel has a suitable quenching medium . This environment, air, oil, hot bath can . Hardening of the parts when the hot bath water will be held until the bath temperature equilibrated . Wait for it to cool to 80 º C , the most ideal , then rinse with hot water to get into the tempering furnace is . Quenching, tempering step by step part of the room temperature drops to cracking or breakage may occur. So I will go tempering untouched will be tempered to a temperature has dropped .

      Shaped parts in the hot water washing is very important for water -salt bath . On the part enters the tempering with salt residues consisting of strong acid with t the point where the effect of high temperatures begin carving . Heat treatment in the track from the user does not notice salts , pitting during operation continues . Early or late breaking with the show itself. Therefore, if small parts must be welded from salt bath , the hot water and large should be brushed with a wire brush . It is necessary to remove residual salts . Also, the surface of the part to be oxidized or be shipped is kept immersed in oil .

 

Equilibration : 80 º C of the steel ? After the cooled put into an oven at 100-150 ° C , is held at this temperature . Especially large dies and tools to reach the same temperature for all the sections are critical .

 

Retention time: the time required for austenitizing temperature after leaving the track completely he should start . After austenitizing temperature of the oven reaches the part is expected to reach the austenitizing temperature . After this holding period starts running . The difference depends on the time interval following features :

v Parts on the size of

V shape (round , flat , cube)

have on the capacity of the oven , the genus

v Heat to

Part of whether you have packed packed

 

The advantages of vacuum heat treatment

· Corrosion- end ; clean shiny surfaces

· Avalanche full kontrolü.dekarbürizasyo point and an end to rekarbürizasyo

· A more uniform surface and core structure

· Less deformation

 

Protective and pressurized gas -assisted convection heating with the advantages of

· Low temperature uniform heating

· Faster and time-saving operations

· Charging and out of the oven and bake hardening - tempering process without moving the possibility of making a succession of

· Gas and energy saving

· Low leisure time and more efficient use of facilities

 

These benefits along with the system ;

· Computer-controlled

· Automatic is programmed

· This system of traceability , repeatability and quality ensures the continuity of

 

Industrial vacuum heat treatment technology

 

Pressure gas turbine at low temperatures and with the help of pre- fast convection heating

 

 



27.12.2013 11:03:07
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