RU2695857C1 - Method of increasing resistance to abrasive wear of frame and resource of composite ploughshare of plow bodies - Google Patents

Abstract

FIELD: machining of metals.

SUBSTANCE: invention can be used in making composite ploughshare and hardening of undercutting area of its frame in process of restoration. Layer of abrasive-resistant alloy rolls is deposited on rear and outer sides of undercutting area alternately. Welding of rolls is performed along the entire length and width of ploughshare. First roller is formed on the back side of the undercutting area at distance of 4–5 mm from the blade tip, and the next rolls are applied at the distance between them of 3–4 mm at width of rollers of 10–12 mm. Each next roller is applied after cooling of previous to 40…60 °C. Welding metal beads are formed with hardness of not less than 58–62 HRC with inclusion of HRA80-84 in the structure. Surfacing of hardening layers is performed on width of frame, which limits its operability in accordance with agrotechnical conditions.

EFFECT: method provides higher resistance to abrasive wear of composite ploughshares' skeleton and increases their service life, with reduced tendency to formation of cracks and violation of geometric shape with observance of agrotechnical standards for soil treatment.

1 cl, 2 dwg

Description

The invention relates to the field of agricultural engineering technology, in particular to increasing the wear resistance and resource of composite plow shares and can be used in the manufacture of these parts, as well as during hardening in the recovery process.

The uneven pressure from the soil in certain areas of the working surface of the plow share provides uneven intensity of their wear [1]. In relation to composite shares, the resource is limited by the resistance to abrasive wear of the cutting area of the core, and the ultimate state is determined by its complete abrasion. As a rule, the width of the cutting part is from 50 to 60 mm, while for all-metal shares, it does not exceed 30 mm. An increase in the abrasive wear resistance of a given section of a part can be achieved by various methods, which, first of all, include surfacing of a material of increased hardness [2, 3].

Known compound ploughshare manufactured by the Kverneland Group company, the increased abrasive wear resistance of which is achieved by thermal hardening of the core throughout the volume to a hardness of 45-50HRC [4]. According to studies [5], its resource for plowing soils with high wearing ability (sandy loam soils) does not exceed 28-30 ha, which cannot be considered sufficient in the current state of agricultural production.

The closest technical solution, selected as a prototype, is a method of increasing the durability of composite plow shares by butt welding to the remaining part of the core, heat-strengthened to 50HRC, the compensation plate instead of the worn zone, followed by welding of the back side of the blade region with an alloy of 58-62HRC hardness length and over the entire width [6].

Such hardening allows to increase the wear resistance of the blade and, to a certain extent, the share share. However, the potential capabilities of the skeleton, in terms of increasing the resource, in this case remain not fully exhausted, and therefore the method under consideration does not meet the technological requirements for ensuring high MTBF. Another disadvantage of this technology is the significant level of residual stresses of the hardened area, often leading to the appearance of cracks in the coating and in the part itself, as well as to a violation of the geometric shape established by the agrotechnical requirements for plowing.

The technical result of the invention is to increase the resistance to abrasive wear of the skeleton of composite plowshares and increase their resource, while reducing the tendency to crack and violate the geometric shape in compliance with agrotechnical standards for tillage.

The technical result is achieved by the fact that the deposition of a wear-resistant alloy of high hardness is performed, alternately with the back and outer (working) sides of the core in the form of rollers 10-12 mm wide. Moreover, their formation is carried out along the entire length of the product, starting from the back of the blade part with a shift from the blade tip by 4-5 mm. The subsequent roller with the same geometric parameters is applied to the working surface with a height offset from the previous one by 3-4 mm after it is cooled to 40-60 ° C. Then the process repeats. The application of rollers is carried out on the width of the skeleton, limiting its operational state in accordance with agro-technical conditions. The hardness of the coating material should be about 58-62HRC in the presence of inclusions with a hardness of about 80-84HRA in the structure of the weld metal.

Significant hardness of the metal of the rollers and the presence of inclusions with 80-84HRA in it provide a high level of abrasive wear resistance of the hardened zone, and the arrangement of the layers alternately (in a checkerboard pattern) on the outer and back sides of the core can significantly reduce its wear rate. The presence of these two factors creates the conditions for a significant increase in the share share as a whole.

The application of a separate layer is accompanied by cooling to 40 ... 60 ° C before the formation of the next, contributing to a decrease in residual stresses due to a decrease in the degree of influence of thermal effects from surfacing. The relatively low width of the rollers will also negatively affect the growth of stresses. The arrangement of the layers on both sides of the skeleton in a checkerboard pattern in width, to a certain extent, provides mutual compensation for the generated stresses due to their different signs. In the cross section of the deposited section there are tensile stresses (σ ₁ , σ ₂ , σ ₃ , σ ₄ ), but since they act opposite on both sides, they will partially neutralize (Fig. 1: 1 fragment of the core cross section ; 2-reinforcing rollers). Taken together, the above factors (cooling of each layer, insignificant width of the rollers and mutual compensation of residual stresses) will reduce the likelihood of cracks and changes in the shape of the skeleton, thereby ensuring compliance with agro-technical requirements for plowing.

The offset of the first roller from the edge of the blade by 4-5 mm will avoid burning out the base metal, and observing the distance between the layers of 3-4 mm will reduce the degree of influence of the temperature of the heat affected zone on the structure of the metal of the core.

The formation of a hard coating can be done manually or semi-automatically by electric arc welding.

The claimed method is carried out due to a number of factors:

- the first - the abrasion-resistant layers are surfaced on both sides of the cutting part of the core alternately, (then on one, then on the other), provided that the subsequent surfacing is performed only after cooling of the previous metal to 40 ... 60 ° C;

- second - the deposited material must have a hardness of at least 58-62 HRC with the presence of inclusions with HRA80-84 in the structure.

- the third - the first layer is formed on the back of the cutting area at a distance of 4-5 mm from the edge of the blade, the subsequent ones are applied with a distance between them of 3-4 mm;

- fourth - the width of the rollers should be in the range of 10-12 mm.

Using the developed method will provide a significant increase in resistance to abrasive wear of the undercutting part of the skeleton due to: high hardness of the coating (58-62HRC); the presence in the weld metal of inclusions with HRA80-84; reducing the wear rate of the hardened area due to the presence of abrasion-resistant material on the outside (working) and back sides.

An increase in the share share after hardening is achieved by increasing the resistance to abrasive wear of the cutting part.

The application of a wear-resistant alloy in compliance with the conditions consisting in two-sided surfacing, when the subsequent layer is formed after cooling the previous one to 40 ... 60 ° C, with a roller width of 10-12 mm and a distance between them of 3-4 mm will reduce the tendency of the hardened part and the surfacing area to an increase in residual stresses and, accordingly, warping and cracking both in the coating and in the core itself.

A comparative analysis of the claimed solution with the prototype shows that the claimed method differs from the known one in that the abrasive wear resistance of the plow share is achieved by surfacing on the back and outside of its cutting part of alternately hard layers with HRC58-62 units and the presence of inclusions in the structure of the deposited metal with 80-84HRA, rollers with a width of 10-12 mm and a distance between them of 3-4 mm when applying the first to the back of the blade, departing from the tip 4-5 mm.

Thus, the proposed method meets the criterion of "novelty."

Known technical solutions involve the deposition of wear-resistant material only on the back side of the cutting-blade part with the formation of a coating along its entire length and over the entire width, which is absent in the claimed method, and gives reason to conclude that it meets the criterion of "significant differences".

In FIG. 2 shows a fragment of the skeleton of a composite ploughshare 1 with mounting holes 7 and a weld bead 2 on the blade part from its rear side, a bead 3 formed on the working side, and also beads 4 and 5 weld to the full width of the cutting part 6 of the skeleton. (The solid thickened line shows the cutting area. The rollers located on the back are shown by dashed lines).

The implementation of the claimed method in General is expressed by the technological process, consisting of the following operations:

1. Stripping of the cutting part to a metallic sheen;

2. Removal of residual sludge from stripping;

3. Surfacing of wear-resistant alloy with a width of 10-12 mm on the back surface of the blade region with a distance from the tip of 4-5 mm;

4. Cooling of the formed layer to 40 ... 60 ° C;

5. The wear-resistant alloy is deposited on the working side of the cutting-blade part at a distance of 3-4 mm from the previous layer;

6. The repetition of the surfacing process on the width of the cutting part, which determines the operational state of the core.

Field comparative tests of plowshares, hardened by the technology described in the prototype and by the proposed method showed an increase in the resource of the latter by 1.4 ... 1.6 times. For electrode surfacing, we used Castolin Eutactic self-shielded flux-cored wire of TeroMates AN 4660 brand based on high-chromium cast iron with niobium, providing a formed metal hardness of about 59 HRC and the presence of carbides with HRA80-84 in the structure.

Surfacing mode parameters: wire diameter (d _e ) - 2.8 mm; welding current strength (I _St ) - 250 A.

Information sources:

1. Mikhalchenkov A.M., Kozarez I.V., Mikhalchenkova M.A. Depreciation of all-metal and composite plowshares // Tractors and agricultural machinery. - 2014. - No. 7. - S. 39-43.

2. Izmailov A.Yu., Sidorov S.A., Lobachevsky Y.P., Khoroshenkov V.K., Khlusova E.I., Ryabov V.V. New materials and technologies for applying carbide coatings for parts of tillage machines // Bulletin of Russian Agricultural Science. - 2016. - No. 2. - S. 66-69.

3. Kolomeychenko A.V., Titov N.V., Kondrakhin N.A., Litovchenko N.N., Podzharaya K.S. Investigation of the technological capabilities of the carbon-arc method of hardening the working bodies of tillage machines // Technique and equipment for the village. - 2015. - No. 2 (212). - S. 24-26.

4. Mikhalchenkov A.M., Soloviev S.A., Novikov A.A. About one reason for the low resource of parts of the working bodies of domestic tillage tools // Transactions of GOSNITI. - 2014. - T. 7. - S. 127-132.

5.http: //eco-technika.com/d/1158586/d/test_lekhemov_unirol.pdf 04/12/2018.

6. Mikhalchenkov M.A., Yakushenko N.A. A method of hardening restoration of a plow share // Russian Patent No. 2544214. 2015 bul. Number 7.

Claims (2)

1. A method of manufacturing a ploughshare share of the plow body with hardening of the cutting region of its core, comprising surfacing a layer in the form of rollers of an abrasion-resistant alloy on the back and outer sides of the cutting region alternately, characterized in that the welding of the rollers is carried out along the entire length and width of the ploughshare, while the first roller is formed on the back of the cutting area at a distance of 4-5 mm from the edge of the blade, and subsequent rollers are applied at a distance between them 3-4 mm with a width of rollers 10-12 mm, with each subsequent roller is applied last preceding cooling to 40 ... 60 ° C. 2. The method according to p. 1, characterized in that the deposited metal rollers are formed with a hardness of at least 58-62 HRC with the presence of inclusions with HRA80-84 in the structure.

Images