RU2484937C2 - Method of weld reconditioning of tillage machine tools - Google Patents

Abstract

FIELD: process engineering.

SUBSTANCE: method relates to weld reconditioning of worn-out parts operated in abrasive medium. Worn-out surface is removed to make compensate insert that traces said worn-out part. Said compensate insert is hardened by heat treatment. Said insert is welded to unworn part. Parts are surface-hardened by applying bulges on reconditioned working surface perpendicular soil transfer path to overlap the fixing seam.

EFFECT: recovered tool strength, resumed life.

3 dwg

Description

The invention relates to the field of repair of tillage, earthmoving and loading machines, in particular to the restoration and hardening of worn parts working in the soil environment, and can be used to renew the resource of structural elements of construction, agricultural and road equipment.

A known method of restoring parts of tillage machines (patent No. 2225256, MKI B23P 6/00), including removing the worn working part with a grinding cutting wheel, making a compensating insert from steel in the form of an angular plate, sharpening it with the formation of a blade, hardening by electrolysis boring, followed by fastening by screws to the remaining unworn area [1].

The disadvantages of this method are: the deviation of the design of a stopped paw from agrotechnical requirements, the presence of plate fasteners, the use of an expensive electrolysis boronation process, the high complexity of the process.

Closest to the proposed method is a method in which the rejected products worn part is removed by a grinding cutting wheel using an angle grinder. To restore the geometry of the part, additional plates made of low carbon steel and copying this part are used. Having previously insulated the welding edges, the plates are subjected to electrolytic boronation. After chemical-thermal hardening, the corner plate is welded to the reconstructed paw by manual electric arc welding (patent No. 2241586, MKI B22P 6/00) [2].

However, the process of welding the hardened corner plate to the restored leg made of steel 65G entails a change in the properties of the coatings previously obtained by the chemical-thermal method in the direction of reducing wear resistance. The small depth of the hardened layer will also not allow to achieve a significant increase in abrasive wear resistance and, as a result, the corresponding operating time to the limit state. Equally important is the complexity of the proposed technology.

The technical result of the invention is the renewal of the resource of the worn part with its simultaneous increase, as well as providing the necessary strength of the restored area and improving the crumbling of the soil by welding hardened by heat treatment plates to the unworn part of the product and subsequent surfacing reinforcement of this section. At the same time, steel plates must contain at least 0.5% carbon and copy the geometric shape of the part lost during operation.

The indicated result of the invention is achieved by removing the worn part, manufacturing a new working part from steel that has undergone hardening heat treatment and copying the geometry of the worn part, welding it to the restored product by manual or semi-automatic arc welding with surfacing by reinforcing the working surface with rollers to increase the strength of the welded joint and increase wear resistance .

The claimed method is carried out due to the following. Prepared structural elements having the configuration of the worn part are welded (usually butt) to the metal of the product being restored, not subjected to wear, or subjected to a small extent. The abovementioned structural elements are preliminarily prepared in such a way that they meet the technical standards of the part in the factory version or exceed them, in particular in hardness, i.e. preliminary heat treatment is carried out (quenching followed by medium temperature tempering) on a reed structure with a hardness of 40-50 HRC. In some cases, you can use parts that have worked out their life, but have retained their hardness within the above limits. As an example, leaflets of springs. Welding is performed by electrodes with a low-carbon core in order to avoid the appearance of suture and near-weld cracks, due to the presence of a large amount of carbon (at least 0.5%) and quenching structures in the welded parts. In order to increase the strength of the welded joint, welding should be done in pre-cut edges. Subsequent surfacing reinforcement provides the conditions for creating the necessary strength of the welded joint, increases abrasive wear resistance [3] and contributes to better soil crumbling due to the rollers protruding above the working surface. Rollers are recommended to be welded perpendicular to the movement of the soil, but in such a way that they overlap the weld between the welded structural element and the body of the unworn part of the part (fixing seam). The length of the rollers is determined by the width of the working surface, the distance between them should not exceed 40 mm.

A comparative analysis of the claimed solution with the prototype shows that the claimed method differs from the known one in that the restoration of the part is ensured by welding a structural element that copies the geometry of the worn part (compensating insert) to the remaining unworn (slightly worn) part. The welded element is preliminarily subjected to heat treatment to increase hardness and, as a result, an increase in abrasive wear resistance occurs. The formed working surface is reinforced by welding rollers on it. The geometry of the rollers and their location is determined by: the mechanical composition of the soil, the trajectory of its movement relative to the working surface, the type of work performed. Thus, the proposed method meets the criterion of "novelty."

Known technical solutions involve either welding a new working part, or securing it in another way to an unworn part of the product with preliminary hardening by electrolysis boroning, and do not involve hardening heat treatment and additional surfacing after welding of the compensating insert, which is absent in the proposed method and allows us to conclude about its compliance with the criterion of "significant differences".

Figure 1 shows the unworn part of the details of the tillage organ (lancet paw of the cultivator) after alignment of the worn field crop, where 1 is the remaining part of the part after operation.

Figure 2 presents the part with a welded-in compensating for the worn-out area insert, where 2 is the worn-out area of the part; 3 - compensating insert; 4 - welding seam.

Figure 3 presents the restored and hardened part, where 5 - reinforcing rollers.

The implementation of this method is illustrated by the example of restoring a worn lancet paw of a cultivator. The rest of the part 1 (Fig. 1) is aligned according to the pattern. Then, to the aligned unworn part 2 (Fig. 2), a compensating insert 3, which copies the worn section, is welded by a weld 4. After this, the surfacing of the reinforcing rollers 5 (Fig.3) is carried out perpendicular to the weld, connecting the compensating insert and the aligned part of the part. When welding and surfacing, an electrode with a low-carbon rod type UONI with a diameter of 4 mm is used. The strength of the welded current is 160-180 A.

Information sources

1. Patent RU 232556 C1. A method of restoring the paws of cultivators of tillage machines [text] / Buylov V.N., Lyulyakov I.V., Volosevich N.P., published 05.27.2008.

2. Patent RU 2241586 C1. A method for the restoration of parts of tillage machines [text] / Buylov V.N., Lyulyakov I.V., published on December 10, 2004.

3. Patent RU 2274526 C1. The method of hardening plowshares of plows from medium-carbon and high-carbon steels [text] / Mikhalchenkov A.M., Ganeev Yu.M., Budko S.I., Kaposhko D.A., published 02.20.2005.

Claims (1)

A method for hardening the restoration of parts of tillage machines, including removing the worn part, manufacturing a compensating insert that copies the worn part, and attaching it to the unworn part by welding, characterized in that the welding is pre-hardened by heat treatment of the compensating insert and the welding reinforcement is applied by applying rollers to the restored working surface perpendicular to the path of movement of the soil with the overlapping of the fixing seam.

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