RU2279338C1 - Method for producing cutting tool with soldered cutting tip - Google Patents

Abstract

FIELD: manufacture of cutting tools with soldered cutting tip of hard alloys, super-hard cutting ceramics or quick-cutting steels.

SUBSTANCE: method comprises steps of making craters on surface of cutting tip and on surface of holder body in zone of soldering cutting tip; soldering cutting tip to holder body and cooling parts. Diameters of craters are commensurable with thickness of belt solder and with predetermined value of gap between soldered surfaces. Craters are formed by mechanically pressing in or with use of laser.

EFFECT: enhanced strength and quality of welded seam, improved operational properties of thin-blade cutting tool.

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Description

The invention relates to the field of mechanical engineering, in particular to tool production, for the manufacture of a special thin-blade tool with a soldered cutting plate of hard alloys, superhard cutting ceramics and high-speed steels.

It is known to carry out soldering during high-frequency or open gas-flame heating of a tool equipped with carbide plates of cutters, boring, boring, cutting using tabletized solders and fluxes, providing for the preparation of hard alloy plates with jacking in abrasives, stripping and degreasing (OST 92-4139-79. Soldering carbide tools . Typical technological processes).

The technology is most effective when soldering a standardized tool with large enough alloy plates of VK and TK groups, but does not provide reliable fastening, soldering quality and high performance properties of cutters with thin and small-sized carbide-threaded, slotted, saddle plates.

A known method of traditional brazing in single-turn inductors using compensation gaskets, active boron flux fluxes and as alloys of alloyed brass powders, shavings, and more recently, strips obtained by liquid rolling (Markova I.Yu., Pevzner NB Methods of saving solders in soldering production. Welding production, 2002, No. 1, pp. 39-47 and under the editorship of I.E. Petrunin. Soldering guide. M. Engineering. 1984, 400 pp.).

The disadvantages of the method include insufficiently reliable mounting of the gaskets.

Closest to the claimed is a method of manufacturing a brazed tool, involving vacuum brazing of cutters with high-temperature solders with preliminary laser processing of plates of hard alloys (applying laser craters) and brazing with regulated heating and cooling speeds using copper titanium as solder (AS No. 1555380 , IPC C 21 D 9/22, BI No. 13, 1990, prototype).

The method has the following disadvantages: it is rather laborious, the degree of filling of pointed cone laser craters in hard alloys is difficult, the soldered joint has an increased fragility. The premature chipping of cutting parts with significant contact loads and complex stress conditions during the processing of precision parts from viscous stainless steels and alloys based on nickel and cobalt used in the production of electric propulsion thrusters (small-thrust electric jet engines) and TIPs (plasma sources) is not ruled out. Special cutters are mainly applicable for finishing turning.

The objective of the invention is to increase the strength and quality of the junction of the cutting insert with the housing holder, which leads to improved operational properties of a thin-blade cutting tool while maintaining manufacturability and ease of implementation in conditions of pilot and serial production.

The necessary technical result is achieved due to the fact that on the surface of the holder body before soldering in the place of soldering of the cutting insert, holes are formed whose diameter is 0.1-0.2 of the thickness of the cutting insert, and the depth of the holes is taken equal to the size of the gap between the parts. It is also envisaged that the holes on the holder body be overlapped by the diameter of the holes on the cutting inserts by 0.5-0.6, as well as the formation of holes using laser irradiation and holes on the cutting plates of high-speed steels by mechanical indentation using a hardness tester indenter and use solder tape for soldering with a thickness equal to the depth of the holes.

The formation of holes on the nests of the body-holders improves the conditions of wetting, spreading of solder. The gap filling is improved during high-frequency soldering due to the choice of geometry, smoothness of the edges of the holes in comparison with the known craters of irregular needle geometry, obtained, for example, by laser sharp focus on hard alloys. In this case, the degree of symmetry and overlap is selected taking into account the type of tool, its loading during cutting and ensuring the formation of a “rivet connection” of the brazed surfaces with each other after the solder has hardened.

The accompanying description of the drawings shows:

figure 1 - the nature of the formation of the soldered seam during high-frequency brazing of incisors with holes in carbide plates, where 1 is a plate, 2 is a body, 3 is a hole;

figure 2 - the microstructure of the soldered seam during high-frequency soldering of incisors with holes in the body-holders;

figure 3 is the initial state of the holes;

figure 4 - filling of large holes with solder in kink when they are in a chaotic arrangement;

figure 5 is the optimal arrangement of nests on thin carbide inserts.

The method involves the creation of holes with smooth edges in depth equal to the thickness of the tape solder, and a given gap between the soldered surfaces. The use of Rockwell instruments used to measure the hardness of steels and alloys with conical or ball carbide indenters as a tool for depositing holes simplifies the complexity of the process.

The invention is illustrated by examples of practical implementation of the method on several types and types of special cutting tools.

For the manufacture of thin-blade cutters with an extended overhang of the working part according to the proposed method, carbide tungsten-cobalt plates VK, titanium-cobalt groups TC according to GOST 4872-75, GOST 25397-82, GOST 25395-82, as well as two-and single-layer plates of superheated ceramics "Hexanite" were used , "Silinit" of Poltava STM plant and plates of high-speed steels R6M5-P, R6M5-MP, R6M5K5-P of the St. Petersburg plant tool. Holding cases were made of forged bars of steels with a low critical hardening rate, martensitic class 4X5MFS, 4KhZVMF according to OST 92-1137-86.

Heating by high-frequency brazing of the plates was carried out on high-frequency installations LGZ-67, VCHI-2-60-0, 66, laser holes on carbide plates and superhard ceramics were formed on a Kvant-16 installation, holes on holder bodies were formed by pressing indenters on instruments hardness measurements TK-2M, TK-ZMI. The soldering was carried out by modern tape solders of the P-47, PS-47 "Alarm" grade and flux pastes FKP-250 "Alarm" according to TU 48-17228138 / OOP-004-2001, TU 48-17228138 / OPS-018-2003.

Example 1

Saddle cutters for machining frames made of soft magnetic steel 16HV-I were made and soldered according to the proposed technology. Wells with a diameter of 0.4 mm, a depth of 0.3 mm, equal to the thickness of the P-47 solder strip were deposited on carbide inserts VK-60M with a laser, and holes were pressed onto the groove surface of the holder bodies made of 4X5MFS steel with a 1/16 inch diameter ball at load 60 kgf on Rockwell, asymmetric to the holes on carbide inserts. Asymmetry with an overlap of up to 0.5 mm was achieved by placing plates 2 × 2 × 10 mm (Fig. 5, above) during HDTV soldering with offset in the groove of the holder of the plates relative to the holes on the hard alloy.

As a result of soldering at 1050 ° C with a holding time of 5-6 seconds and cooling in air, high-shear junctions with a shear of up to 275 MPa were obtained when the holes were completely filled with solder both on the side of the plates and grooves, which was facilitated by the preliminary application of FKP-250 flux paste on hole surfaces with a spatula, before soldering and reliable depassivation of soldered surfaces at soldering temperatures with active spreading of solder. The wear resistance and operating time of the cutters increased by 2 times compared to brazed by known technology.

Example 2

Cutters are boring, special, with an extended overhang of the cutting part, for processing thin-walled chamber-insulators ЭРД МТ from heat-resistant, hot-pressed ceramics, boron silicon-silicon, BHP were soldered according to the developed technology. In this case, two-layer plates made of Hexanite-R with a sublayer of VK hard alloy before soldering were laser treated to form holes with a diameter of 0.2 mm or 0.1 of the plate thickness, identical wells were applied to the housings of 4X3VMF steel by pressing the carbide cone pyramid onto Rockwell device, similar to those shown in figure 3 (upper row).

After the formation of the holes, randomly located randomly on the surfaces of the carbide substrate of the ceramic plates and in the nests of the solder housings, the wells were filled with flux paste and soldered with short-time heating of 980-1000 ° C with P-47 Alarm alloy. During the heating process for soldering the thin portion of the holder is fully warmed, and with cooling in air leaked martensitic transformation of the steel 4H3VMF, increased hardness to LDC _e = 32-34, the tensile strength of the steel after quenching was incomplete σ _in = 1120-1120 MPa, to thereby holder stiffness when cutting thin-walled parts made of ceramics BGP. The treatment allowed to increase the wear resistance of the cutters, to exclude the tearing off of the plates during cutting, at the same time the class of processing cleanliness increased, there was no brittle fracture of thin-walled insulators during the cutting process. With minimal costs for the preparation and soldering of special cutters, their operational properties are almost doubled in comparison with the known methods of manufacturing and processing.

Example 3

Cutters for machining parts from the TsM-10 molybdenum alloy, capsules of the ERD MT cathodes were made according to the proposed method, equipping the tool holders from 4X5MFS steel with plates from R6M5-MP TVCh powder high-speed steel with simultaneous hardening from the soldering temperatures with PS-47 ALARMet soldering mixture "

Before soldering, holes were pressed randomly on the surface of the holders of the holder bodies and on the surface of the plates of high-speed steel by pressing a ball indenter on a TK-2M instrument with a distance between the wells of 1.6-2.0 mm and a hole diameter of 0.2-1.0 mm. Then, after applying the solder mixture, brazing was carried out at heating temperatures of 1060-1070 ° C, followed by cooling of the cutters in a stream of air and with a low tempering of 200 ° C for 2 hours.

Brazed cutters had a hardness of the cutting part of the NKS _e = 63-64, a hardness of the holder in the soldering zone of the NKS _e = 40-41, full penetration and high joint strength τ _{cf were} ensured _. = 320-330 MPa, higher than in the known methods of manufacturing cutters. The wear resistance during the processing of molybdenum parts with a strength of 480-490 MPa increased by 1.8 times. Figure 2 shows the microstructure of the soldered seam with the formation of holes by mechanical deformation of materials in the initial state.

The experiments showed that in the manufacture of tools soldered with inserts cutting all classes of instrumental materials with the formation of holes according to schemes outside the claimed, the positive effect is the strength of the junction, the degree of penetration, the mutual displacements of the soldered elements deteriorate and, as a result, the maximum positive effect of the developed technological schemes for the manufacture and processing of cutters.

Claims (6)

1. A method of manufacturing a cutting tool with a soldered cutting insert, comprising forming holes on the surface of the cutting insert, soldering it to the holder body and cooling, characterized in that holes are formed on the surface of the holder body in the place of soldering the cutting insert, the diameter of which is 0, 1-0.2 thickness of the cutting insert, and the depth is equal to the size of the gap between the parts. 2. The method according to claim 1, characterized in that the holes on the holder body are overlapped by the diameter of the holes on the cutting inserts by a value of 0.5-0.6. 3. The method according to claim 1, characterized in that the holes on the cutting inserts are formed using laser irradiation. 4. The method according to claim 1, characterized in that the holes on the cutting plates of high-speed powder steels are applied by mechanical indentation. 5. The method according to claim 1, characterized in that the holes on the holder body are formed by indentation using a hardness tester indenter. 6. The method according to claim 1, characterized in that for soldering use a tape solder with a thickness equal to the depth of the holes.

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