Warped metal
These deformations are caused by the application of heat and force during machining.
Cutting at metal speed (Yumoto Denki) is a process that uses a blade that rotates at high speed or a material that is rotated at high speed to attack the blade to scrape the material.
This is a processing method that places a large load on the blade and material.
Warping is
literal meaning of material.
When placed on a flat table, light leaking from the gap between the workpiece and the table is visible, making it possible to confirm even small warp threads.
Distortion is
variable speeds such as expansion, contraction or torsion occur when an external force is applied to the object.
The object deforms and expands or contracts with the applied external force.
For example, if you pull a metal bar, it will extend in the direction in which it was pulled.
The rate of deformation from the original shape at this point is called deformation.
Distortion type
Vertical deformation and horizontal deformation
Vertical deformation: Variation in elongation and contraction in the length direction of the round bar.
Lateral tension: A change in radial direction.
Static deformation deformation and and strain strain strain
static: Filtering changes slowly over time.
For example) Strain etc... due to structural deterioration over time
Dynamic distortion: Strain changes over time.
For example,
there is no clear definition between deformation and dynamic deformation experienced by the vehicle when applying brakes.
Stress
The cause of the deformation is residual stress.
Residual stress is the stress that exists in an object even after the removal of external forces.
Typically, a constant shape is maintained by balancing the force applied from the inside to the outside of the object and the force applied from the outside to the inside.
If this balance is lost, deformation occurs in the direction of applying more force.
The greater the externally applied force, the greater the residual stress and the greater the residual stress, the greater the strain.
Initially, residual stresses in the formation of the material remain in the material.
Therefore, when processing, attention should be paid to the residual stress of the material.
Handling is likely to cause warping and deformation
Hard material Material
hardening places a particularly high load on the material during the cutting process.
Since residual stress increases with the size of the load, it is a material that is likely to warp or deform.
When Rockwell hardness exceeds HRC60, the cutting process becomes difficult.
Thin shape
Easily warped when processed into thin shapes.
The thinner it is, the warpier it is.
Even if it is fixed and secured by a die, warping and deformation can occur if the jig is removed.
Casting
The metal expands when heated and shrinks when cooled.
Casting is a method of melting metal at high temperatures and pouring it into a mold.
Depending on the shape formed, the rate of cooling depends on thickness and location.
Sections are thin and the surface hardens quickly, and thick and internal sections take time to cool.
The interior, which takes a long time to cool, has residual stress in the direction of pulling the base material around, causing deformation.
Welding
It can be said that distortion can occur due to changes caused by cooling → local heating.
When a metal is heated, the bond between the metal's atoms weakens and expands.
However, since it is fixed to the surrounding base material, no deformation occurs in a state where the bonding force between the weak atoms and the original state is maintained.
As it cools, it regains its cohesive strength and tries to contract.
When this contractual force exceeds the binding force of the surrounding matrix, it appears as a deformation.
The surrounding base materials are soft and susceptible to deformation, and buckling deformation (deformation in a wavy shape) occurs with thin sheet materials.
Forces that do not appear as deformation are still residual stresses in the material.
Specifically, deformation resulting from welding an aluminum sheet is capable of causing angular deformation and bending deformation in the plane direction where no bonding force is applied.
Aluminum itself is not suitable for welding, but welding tends to cause deformation.
Steel processing
stainless Stainless steel (SUS) has extremely poor thermal conductivity properties.
(Refer to the article about “Features of Stainless Steel (SUS): why it doesn't rust, use and maintenance ().
Usually, the heat generated during processing escapes to the workpiece or shell, but in the case of stainless steel, it escapes from the workpiece. The amount of heat is reduced.
heat is accumulated in the end of the tip, shear resistance by tool friction is increased, it leads to a more vicious cycle of processing heat being generated.
When the processing heat is increased, the breakage thread of this tool will rather distort the stainless steel as an object to be cut.
to reduce the hassle of such processing, skilled craftsmen have ingenuity with day-to-day processing methods.
Metal Speed supports various processes such as milling, machining and turning.
Please for metal machining, aluminum machining, stainless steel machining and metal machining for Metal Speed.
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