Method for Producing a Stainless Steel Sheet with Modified Visual Characteristics

Abstract

A method for producing a patterned stainless steel sheet with improved visual characteristics in the wavelength area of visible light including providing a deformed stainless steel sheet; performing a heat treatment on the deformed stainless steel sheet, wherein the heat treatment is conducted at a temperature of 900-1200° C.; performing a mechanical treatment on at least one surface of the heat treated stainless steel sheet; transferring the mechanically treated stainless steel sheet to a patterning process, wherein, in the patterning process, at least one side of the mechanically treated stainless steel sheet is patterned using a patterning roll having a surface with an emboss depth of up to 100 micrometers to provide a patterned stainless steel sheet; and performing a heat treatment on the patterned stainless steel sheet, wherein the heat treatment is conducted at a temperature range of 900-1200° C., wherein the mechanical treatment is carried out by blasting.

Claims

1. A method for producing a patterned stainless steel sheet with improved visual characteristics in the wavelength area of visible light, the method comprising: providing a deformed stainless steel sheet having a thickness of 0.3-3.5 mm; performing at least one heat treatment on the deformed stainless steel sheet, wherein the heat treatment of the deformed stainless steel sheet is conducted at a temperature of 900-1200° C.; performing at least one mechanical treatment on at least one surface of the heat treated stainless steel sheet; transferring the mechanically treated stainless steel sheet to a patterning process, wherein, in the patterning process, at least one side of the mechanically treated stainless steel sheet is patterned using a patterning roll comprising a surface having an emboss depth of up to 100 micrometers to provide a patterned stainless steel sheet; and performing at least one heat treatment on the patterned stainless steel sheet, wherein the heat treatment of the patterned stainless steel sheet is conducted at a temperature range of 900-1200° C., wherein the mechanical treatment before the patterning process is carried out by blasting.

2. The method according to claim 1, wherein the heat treatment of the deformed stainless steel sheet is conducted at a temperature of 1150-1200° C.

3. The method according to claim 1, wherein the heat treatment of the deformed stainless steel sheet is an annealing and pickling process.

4. The method according to claim 1, wherein the heat treatment of the deformed stainless steel sheet is a bright annealing process.

5. The method according to claim 1, wherein the heat treatment of the patterned stainless steel sheet is conducted at a temperature of 1150-1200° C.

6. The method according to claim 5, wherein the heat treatment of the patterned stainless steel sheet is carried out as an annealing and pickling process.

7. The method according to claim 5, wherein the heat treatment of the patterned stainless steel sheet is a bright annealing process.

8. The method according to claim 1, wherein the heat treated patterned stainless steel sheet is tension levelled.

9. The method according to claim 1, wherein the stainless steel sheet is austenitic stainless steel.

10. The method according to claim 1, wherein the stainless steel sheet is ferritic stainless steel.

11. The method according to claim 1, wherein the stainless steel sheet is ferritic austenitic stainless steel.

12. The method according to claim 1, wherein the patterned stainless steel sheet is applicable as exterior building material, interior building material, automotive steel plate, commercial kitchen equipment, outer plate for home appliances, outer plate for kitchen equipment and kitchen accessories.

Description

DESCRIPTION OF THE INVENTION

[0012] The deformed stainless steel sheet is heat treated before the patterning treatment at the temperature range of 900-1200° C., preferably at the temperature range of 1050-1200° C. The heat treatment for the deformed stainless steel sheet is carried out as an annealing and pickling step or as a bright annealing step.

[0013] The heat treated stainless steel sheet is further treated mechanically on at least one surface of the heat treated stainless steel sheet before the patterning operation. The mechanical treatment before patterning is advantageously carried out by skin-pass rolling with a dull roll or by blasting process in order to have matt blasted surface.

[0014] During the patterning operation, a pattern device, such as a roll, is advantageously used at least on the surface of the stainless steel sheet mechanically treated in order to carry out the patterning process of a desired design onto the surface of the stainless steel sheet. When the patterning operation is only focussed on one surface of the stainless steel sheet a smooth roll is utilized on the opposite side. The emboss depth on the side of the pattern device, such as a roll, is up to 100 micrometre.

[0015] The patterned stainless steel sheet is further heat treated at the temperature range of 900-1200° C., preferably at the temperature range of 1050-1200° C. by carrying out the heat treatment as an annealing and pickling operation or as a bright annealing operation. After the heat treatment the patterned stainless steel sheet can be used as a final product of the method. It is also possible that the heat treated patterned stainless steel sheet is refined, such as tension levelled, in order to have for instance a desired flatness, before the sheet in accordance with the method of the invention is ready as a final product.

[0016] The stainless steel sheet treated according to the method of the invention shows a superior surface homogeneity and has slightly matt but sparkling on each of nuggets of the surface. The surface shows a lower or equal specular reflectance than the value of less than 25% in the prior art, because due to higher sparkling together with the homogeneity of the surface this characteristic is achieved.

[0017] The stainless steel sheet treated according to the method of the invention further shows a specular reflectance of less than 10% in the visible wavelength range, but still shows a sparkling, lively appearance. These desired properties can be achieved when in connection with the heat treatment for the deformed sheet a mechanical blasting process is carried out in order to have a very matt blasted surface on which patterns are formed during the patterning process step.

[0018] The skin-pass rolling for the deformed and heat treated stainless steel sheet before the patterning operation can advantageously be carried out with a textured roll. The skin-pass rolling achieves a roughness R.sub.a of 0.5-2.5 micrometre for the surface which leads to a lower reflectance of the final product and due to the additional texture on the surface in order to increase sparkling in the final product of the method according to the invention.

[0019] The method for producing a patterned stainless steel sheet according to the invention is advantageously at least at intervals continuous, preferably essentially constantly continuous. Therefore, the deformed stainless steel sheet having the desired thickness can be transferred through all the process steps continuously that means lower manufacturing costs and uniform quality, such as homogeneity of the surface for the final product.

[0020] The stainless steel sheet to be used in the method of the invention can be austenitic stainless steel, ferritic stainless steel or ferritic austenitic stainless steel. The stainless steel sheet treated in accordance with the method of the present invention is applicable as exterior building material, interior building material, automotive steel plate, commercial kitchen equipment, outer plate for home appliances, outer plate for kitchen equipment and kitchen accessories.