The subject of the Invention

The invention relates to the flow peening process (GOV process) which increases the strength and lifetime of the material by creating residual stress on the surface of the material after basic manufacturing .

State of the Art

In the known art, some methods are used to increase the mechanical properties of the product by creating residual stress on the surface after machining and chipless manufacturing. An example can be a shot peening process. In this process, the material (workpiece) surface is bombarded using steel, ceramic and glass spherical balls. During the process, thousands of particles that hit the material with the bombardment process beat the entire material surface and create residual stress along the surface. This stress increases the service life of the material to prevent crack formation.

In the present shot peening process, spherical collapses and inhomogeneous stresses occur on bombarded surfaces. These impacts adversely affect the surface smoothness of the workpiece. The surface obtained according to the carrier and particle properties used may happen to be not homogeneous and controllable. In addition, it is difficult to achieve the desired limits of dimensional tolerances. The distribution of the residual stresses along the surface is expected to be homogeneous, while the process parameters are variable, which prevents the formation of a homogeneous surface.

There are some methods in the art that provide a solution to the problem mentioned.

JP2010052123A numbered patent document may be given as an example to the prior art. The present invention subject to the mentioned document is a magnetic polishing method for extremely gentle polishing and easy cleaning of the inner surface of a pipe, comprising a slurry. The fluid paste is sent in the pipe to be polished. Magnetic polishing apparatus is present for movement/agitation of the paste in the pipe. Mentioned paste comprises spherical magnetic particles and abrasive particles. The ratio of the diameter of the abrasive particles to the diameter of the magnetic particles is in the range of 1/4 to 1/1000. The paste retains the particles in a slurry state and does not contain any additives for dispersing the particles.

Document KR20100001560A may be given as another example. The present invention discloses chemical and mechanical polishing equipment comprising ball particles in a polyurethane matrix, thereby preventing scratches on the material surface. The developed equipment includes a polishing head, a wafer, a slurry feeding part, and a polishing pad. The polishing head rotates the upper part of the wafer. The plate (platen) is rotated at the bottom of this part corresponding to the polishing head. The paste feed piece provides a slurry to the sheet or piece for rotation to the top of the piece. The ball particles were randomly formed on the polishing pad. The surface area in contact with the part is maintained in a matrix.

Document KR20160121227A may also be given as another example. The present invention relates to a slurry mixture that polishes. In one embodiment of the present invention, said pulp mixture comprises abrasive particles treated with an alkali solution and a dispersion agent and an additive comprising a polyacrylic and nonionic polymer. In the dough mixture of the present invention, the polyhedral abrasive particles are formed in spherical form by treatment with an alkali solution. Thus, the precipitation of the abrasive particles is prevented and its dispersibility is increased. This results in a high polishing ratio and effective treatment. With the developed mixture, a controllable process can be applied to different types of surfaces. Contrary to the methods described above, it is aimed to develop the flow peening method to increase the surface strength of the products after basic manufacturing without surface polishing and removing any scale from the surface.

Detailed Description of the Invention

The invention relates to a paste mixture (paste set) developed for surface finishing processes and to a method of applying this paste mixture to the workpiece surface by flow forging. The surface strength of the workpiece is increased by the invention.

The flow peening method of the present invention is based on the application of a carrier and retention polymeric paste assembly containing spherical particles by flow to a workpiece surface to form homogeneous, residual stresses on said surface.

The method developed generally comprises the steps of applying a carrier and holding paste mixture containing spherical particles to a workpiece surface by flowing and forging the surface without removing chips from the surface .

One embodiment of the invention is called the GOV process .

The paste mixture applied in the developed method is also within the scope of the invention. The mixture comprises a carrier and retention paste containing spherical particles.

In one embodiment of the invention, the diameters of the spherical particles are different from each other. In one embodiment of the invention, the diameters of the spherical particles are in the range of 0.2-5 mm.

In one embodiment of the invention, the spherical particles are balls .

In one embodiment of the invention, the spherical particles comprise steel and / or stainless steel material.

In one embodiment of the invention, the paste is polymeric.

In one embodiment of the invention, the paste is of high viscosity. In one embodiment of the invention, the paste comprises spherical particles in the range of 10-80%. Preferably, it contains balls in the range of 10-80%.

In one embodiment of the invention, balls of 0.2-5 mm diameter spherical steel and / or stainless steel material are prepared in a very high viscosity paste in a ratio of 10% to 80% of the ball-paste.

It is then applied to the workpiece surface under high pressure.

One embodiment of the invention is applied to all metallic and non- metallic material surfaces according to the diameter of the balls and the viscosity of the polymeric holder and carrier paste.

In one embodiment of the invention, a homogeneous and low surface roughness value is obtained with the polymeric paste tool prepared with balls of different diameters .

No machining is applied to the surface in the method of the invention. In other words, no chip is removed from the surface in any scale. Spherical balls are applied to the surface with polymeric paste pressure. The mentioned pressure is obtained by forcing the high viscosity paste from a large diameter to a small diameter. A hard layer is obtained by forming residual stresses on the surface. In this way, the strength values of the workpiece are improved.

In one embodiment of the invention, the particles are applied to the workpiece surface homogeneously and at the desired pressure.

One embodiment of the invention increases the strength and working time of the material by creating residual stress on the surface. The balls used are preferably of different diameters. It provides forging of the surface, not removing the chip.

In one embodiment of the invention, the residual stresses are homogeneously formed by uniformly applying the balls to the workpiece surface with carrier and holding paste. In addition, the balls are applied to the workpiece surface by flow, not as bombardment. In this way, the surface roughness value of the workpiece is very low. In addition, in contrast to the ball forging process, surface collapse formation is prevented and surface quality is improved.

The invention provides, in contrast to the forging of the surface by bombardment in a conventional ball forging process, the application of spherical particles by flow to the workpiece surface with a specially prepared carrier and retention polymeric paste to achieve residual stresses on the surface.