CS239515B1 - A method of providing steel surfaces with a chromium-containing anti-corrosion coating - Google Patents

Abstract

A method of providing steel surfaces with an anti-corrosion coating containing chromium, especially for parts of mining machines, the purpose of which is to achieve in one layer of the material coating the required properties - a hardness of at least 335 HB and a chromium content of more than 12 percent. The coating is performed by the electrovibration method with a melting electrode in a protective atmosphere so that the axis of the welding nozzle lies in a plane, deviated by 20 o to 40 0 in the welding mixture from the vertical plane, perpendicular to the welding direction. In this plane, it is further deviated by 50 0 to 50 0 from its intersection with the vertical plane, passing through the welding direction. The essence of the solution is that before welding, the surface is provided with a coating of regulating flux and the coating is performed in one layer with an electrode with a chromium content of 15 to 18 percent.

Description

(54) Method of coating steel surfaces with a chromium-containing anticorrosive surfacing

A method of coating steel surfaces with a chromium-containing anticorrosion deposit, in particular for mining machine parts, the purpose of which is to achieve at least 335 HB and a chromium content of more than 12 percent in one layer of the weld deposit. Welding is carried out by the electro vibration method with the electrode being melted in a protective atmosphere such that the axis of the welding nozzle lies in a plane diverted by 20 ° to 40 ^° in the welding mixture from a vertical plane perpendicular to the welding direction. In this plane is further deflected by 50 ⁰ and 50 ⁰ from its intersection with svislourovinou extending direction surfacing. The principle of the solution is that before welding, the surface is coated with a regulating flux and the welding is carried out in one layer by an electrode with a content of 15 to 18 percent chromium.

239 515

- 4,239 SIS

The present invention relates to a method of coating a steel surface with an anti-corrosion deposit with a chromium content by the electro-vibration method and being melted with an electrode in a protective atmosphere, particularly suitable for mining machine components.

Ensuring quality surface protection for mining machinery components operating in aggressive and abrasive environments is of paramount importance for reliable operation, especially of the hydraulic supports of the mine support, on which the safety of the miners depends. These requirements are only partially met by galvanic coated metal coats. It is preferable to provide the surface with an anticorrosive overlay of chromium-nickel steel of the 18-8 type by the electron vibration method in a protective atmosphere of argon. The hardness of one layer is between 175 and 230 HB. In difficult mining conditions and at operating pressures of the hydraulic system higher than 20 MPa, an anticorrosive layer with a hardness of 335 to 380 HB is required. This can not be achieved by the known welding of austenitic steels. The required hardness and corrosion resistance cannot be achieved even by welding of ferritic chromium steels in one layer. Welding of these steels in two or more layers by known MIG, TIG or submerged arc methods results in layers with hardness below 305 HB. The disadvantage, however, is the considerable consumption of welding wire, working time and energy. Since the base material of the part is usually steel of class 11, 12 or 13 with different hardening temperatures, the required properties of the weld deposit cannot be achieved even by hardening and tempering.

238 SIS

The above disadvantages are overcome by the method of coating steel surfaces with an anticorrosive overlay containing a staggering electrode with a deposition electrode in a protective atmosphere, in which the axis of the welding nozzle lies in a plane inclined 20 ° to 40 ° in the welding direction from a vertical plane perpendicular and in this plane it is inclined 30 ° to 50 ° from its intersection with the vertical plane passing through the welding direction according to the invention. The principle of the invention consists in that prior to welding, the surface is coated with a regulating flux and the welding is carried out in a single layer by an electrode with a content of 15 to 18 percent of astonishment.

The main advantages of the method of providing steel surfaces with an anticorrosive surfacing according to the invention are that it allows to achieve the desired properties already in one layer of the surfacing, especially hardness of at least 335 HB and a content of more than 12 percent. Another benefit is the saving of weld electrodes, energy and working time. The method according to the invention can be used to weld flat, curved external and internal surfaces.

The method of providing steel surfaces with an anticorrosive surfacing according to the invention is further described with reference to the accompanying drawings, in which Fig. 1 shows a view of a welded component with a planar surface; Fig. 2 is a view in the direction of arrow 3; FIG. 1 when the deposition is completed. Fig. 3 shows a welded component with a curved surface. Giant. 4 is a view in the direction of arrow R of Fig. 3. Before the welding surface fusing 1 part machined to roughness _and R "3, 2 to 6.3 pm and degreased. The welding is carried out in a single layer by means of an electrode with a content of 15 to 18 percent of astonishment, for example of the quality of 17,041 in a protective atmosphere of an inert gas, for example argon, by the electrovibration method. The axis of the welding nozzle 2 to which the wire-electrode weld spot 3 is fed is in the plane 4, inclined 20 ° to 40 ^c in the welding direction 5 from the first vertical

239 SIS

- 3 planes 5, perpendicular to the welding direction $. The axis of the welding nozzle 2 is simultaneously inclined 30 ° to 50 ° from its intersection with the second vertical plane 6 passing in the welding direction S in plane 4. The distance of the nozzle 2 from the surface 1 is maintained between 15 and 20 mra. The properties of the weld deposit 3 can be further influenced by the fact that before welding the surface 1 is coated with a thin coating of a control flux whose individual components are mixed to a slurry by weight in the range of percentages according to the examples below.

Example 1 (for higher hardness of weld deposit):

Aluminum oxide Al ₂ 0 ₃ 10 - 3%

Metal powder of aluminum Al 2 - 0,5%

Water glass sodium or potassium residue

Example 2 (for lower hardness of weld deposit):

Aluminum oxide Α1 _£ 0 ₃ 35 ± 5%

Boric acid H 3 BO 3 ^R 15-3

Sodium hexafluorosilicate Na ^ SiFg 5 - 1%

Sodium tetraborate Na ^ B ^ O? $ 3 - $ 1

Calcium oxide CaO 30-5%

Al metal powder 12 - 3%

The flux components of Example 2 are mixed with an alcohol, for example methyl alcohol. The welding is carried out after the flux has dried. Upon completion of the surfacing, the surfacing 3 is machined to the required dimension ·

Claims (1)

OBJECT OF THE INVENTION 239 515 Method for coating a steel surface with a chromium-containing electro vibration deposit by means of a method with a melting electrode in a protective atmosphere, wherein the axis of the welding rod lies in a plane inclined 20 ° to 40 ° in the welding direction from the vertical plane perpendicular to This plane is inclined 30 ° to 50 ° from its intersection with the vertical plane passing through the surfacing direction, characterized in that prior to surfacing, the surface is coated with a control flux and the surfacing is performed in one layer with an electrode containing 15 to 18 percent.