RU2259267C2 - Method of making cultivator blade - Google Patents

Abstract

FIELD: agriculture mechanical engineering.

SUBSTANCE: blade is made of two milled strips and holder which are interconnected by means of fusing welding. Before welding, the cutting edge and holder are individually thermally treated. The thermally treated cutting edge of the blade is provided by fusing with a hard alloy of 0.2-0,25 mm thick from above throughout the length and, then, is grinded from bellow.

EFFECT: increased service life.

3 dwg, 1 ex

Description

The invention relates to agricultural machinery, in particular to methods for manufacturing the working bodies of agricultural machines.

A known method of restoring parts, including the processing of worn surfaces and the subsequent application of a wear-resistant coating (AS USSR No. 731659 class. In 23 K 9/04 from 04/25/78 publ. BI No. 31 from 08/23/08).

The disadvantage of this invention is that it does not provide a sufficient amount of wear, and also does not guarantee uniform wear over the entire surface of the parts. The closest in technical essence is the method of manufacturing the paws of the cultivator, which consists in the manufacture of paws and applying to the cutting part of the reinforcing lining, which increases its service life. (French patent No. 2767448, class A 01 B 15/02 of 08/20/97, publ. 02/26/99, ref. Journal "Tractors and agricultural machinery and implements" (separate issue), code 44, VINITI No. RZH 00.3.44.65 P - prototype).

This method significantly increases the wear resistance of the cultivator paws, but due to the fact that the paw is fused from below, uneven wear occurs, since the upper front edge is abraded due to soil flow along the upper surface of the paw. The upper front part of the paw wears out, leaving the lower deposited layer 23 μm thick, which crumbles very quickly, rendering the cultivator paw unusable.

The objective of the invention is to increase the service life of the cultivator paws with uniform wear over the entire surface.

The problem is solved by the method of production of paws of a cultivator, including the manufacture of paws, surfacing of hard alloy on the cutting edge; according to the invention, the paw is made welded from two milled strips and the holder, separate preliminary heat treatment of the cutting edge and holder is carried out, and the hard alloy is deposited on the cutting edge of the paw with a thickness of 0.2-0.25 mm from above over the entire length, followed by sharpening from below.

Analysis of the proposed solution with the prototype allowed us to highlight the features that distinguish the proposed solution from the prototype, which meets the criterion of "novelty."

A comparative analysis of the proposed solution with the known did not reveal solutions whose features coincide with the features of the proposed solution, which meets the criterion of "inventive step".

Figure 1 shows a schematic drawing of a paw with a deposited hard alloy; figure 2 is a section along aa of figure 1; figure 3 is a section bB of figure 1.

The paw of the cultivator 1 consists of a cutting edge 2, holder 3, hard alloy 4.

Surfacing the hard alloy on the previously heat-treated cutting edge of the paw from above increases the wear resistance of the paw due to the fact that there is a slow uniform wear under the cropped soil layer, and the upper raised layer slides along the hard alloy. Due to uniform wear, the sharpness of the cutting edge and its fracture resistance are maintained.

An example of the method

Paw 1 was made welded from two milled strips of steel grade 50 X with a thickness of 6 mm and a stamped holder 3 of sheet steel grade 45 with a thickness of 10 mm. The heat treatment of the cutting edge 2 and holder 3 was carried out separately, before assembly, the cutting edge 2 was processed according to the regime: heating 820-840 ° C, cooling in oil, followed by tempering at a temperature of 270-290 ° C. Rockwell hardness was HR _C = 50-55 units. The holder 3 was subjected to the following heat treatment: heating to a temperature of 840-860 ° C, cooling in water, tempering at a temperature of 220-240 ° C. Rockwell hardness was HRC = 40-46 units.

The heat-treated blanks of the paw 1 were assembled in the conductor for tacking and, after preliminary heating to a temperature of 200-220 ° C, welded by semi-automatic welding in carbon dioxide with a 08G2S welding wire of 1.2 mm diameter, followed by delayed cooling, after which the cutting edge of 2 paws 1 was subjected to abrasive cleaning ensuring a smooth transition from the weld to the cutting edge 3.

Hard alloy 4 was deposited on a heat-treated cutting edge 2 from above over the entire length by the method of electrospark alloying on an EFI-25M installation in the following mode:

- open circuit voltage 35-37 V;

- short circuit current - 135-150 A;

- working current - 70-85 A.

The width of the deposited layer is 15 mm.

Hard alloys VK-8, T15K6 in the form of plates with a thickness of 5-6 mm were used as electrodes.

Metallurgical studies have established that the thickness of the deposited layer is 0.2-0.25 mm, and its microhardness is 850-870 Vickers units.

After surfacing, the cutting edges 2 of the legs 1 were ground from below with an abrasive wheel, providing the necessary sharpness for cutting weeds throughout the entire allowable wear of the legs.

Thus, the proposed method for the production of paws of the cultivator increases the service life with uniform wear of the paws over the entire surface.

Claims (1)

A method of production of a cultivator paw, including the manufacture of a paw, hardfacing of a hard alloy on a cutting edge, characterized in that the paw is made welded from two milled strips and a holder, separate preliminary heat treatment of the cutting edge and holder is carried out, and the hard alloy is deposited on the cutting edge of the paw with a thickness of 0 , 2-0.25 mm above the entire length with subsequent sharpening from the bottom.

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