RU2225275C1 - Method for making discs of molybdenum strip - Google Patents

Abstract

FIELD: machine engineering, possibly in bulb production for making parts of molybdenum strip. SUBSTANCE: method comprises steps of blanking discs out of strip; detecting surface flaws of discs and removing detected flaws by etching; performing detection of surface flaws according to imprints of rolls compared with reference samples; making reference samples due to manufacturing pilot lot of discs; measuring on discs of said lot sizes of roll imprints that are to be removed by etching and preparing according to such sizes reference discs with imprints whose dimensions are admissible for removing by etching; then rejecting discs with imprints of rolls with dimensions exceeding admissible ones. EFFECT: enlarged manufacturing possibilities of method. 1 dwg, 3 tbl

Description

 The invention relates to mechanical engineering and can be used in electrovacuum production (EVP) in the manufacture of parts from strip molybdenum with their subsequent etching in order to clean the surface from defects. Characterization of surface defects in rolled products is provided, for example, by technical specifications for the molybdenum strip of the grade МЧ ТУ 48-19-315-89 "Molybdenum strips for the electric vacuum industry, unannealed." At the same time, the number of defects of the type is regulated: fingerprints of rolls, sinks - dents, traces of stripping, scratches.

 In the manufacture of electronic components, for example, by cutting discs, the technology provides for the control of surface defects, their number. However, there is a requirement for the admissibility of rolled defects on the surface of the disks - the possibility of their removal during subsequent etching.

MCH molybdenum disks are etched in a solution of the composition: hydrogen peroxide - 80 ml, ammonia - 10 ml, distilled water - 10 ml, etching time 3-4 min at a solution temperature of 15-25 ^o С. Before etching, degreasing is performed, after etching - washing in water, rinsing in sulfuric or hydrofluoric acid, washing in water.

 With the existing manufacturing technology of disks, some of them are rejected after cutting by surface defects, thereby reducing the yield, inefficiently expensive metal-roll is spent inefficiently.

 We experimentally established the possibility of etching roll prints using this technology, this most common surface defect in molybdenum bands.

 The closest analogue is a method of manufacturing disks from a molybdenum strip according to the book: IORISH A.E. et al. Fundamentals of the technology for the production of vacuum equipment, Moscow-Leningrad, Gosenergoizdat, 1961, p. 55-57, 62-63, 83-84.

 Disadvantages of the closest analogue: the size of the surface prints of the applied original strip, which can be etched, is not regulated, which leads to the rejection of part of the disks before etching.

 The objective of the invention: to expand the technological capabilities of manufacturing discs from a strip with a smaller rejection of them on surface prints before etching.

 The problem is solved by monitoring the surface defects of the disks by the fingerprints of the rolls according to the samples, while the said samples are obtained by making an experimental batch of disks, determining the sizes of the fingerprints of the rolls to be removed by etching on the disks of this batch, and preparing control disks with fingerprints having sizes that are maximum permissible for removal by etching, and after the said control, discs having roll prints with dimensions exceeding up to empty.

 Common signs with the closest analogue: are made - disks are cut down, controlled for prints, etched, rejected.

 Distinctive features: disks with prints of smaller sizes than on an experimentally installed control sample are not rejected, but are passed to the etching operation.

 In the application (photos a, b).

 Drawing. Fingerprints of the rolls on the surface of the discs: a - the print is long, x2; b - a short imprint and a group of dots, x10.

To implement the method perform the following operations:
1. When developing technology for manufacturing disks, an experimental batch of disks is cut down.

 2. On the one and the other surface of the discs, they are visually fixed using a binocular stereoscopic microscope with a magnification of 6-12 fingerprints, using their classification: linear long, linear short, single point, point clusters (group) - drawing. Set the size of the dot prints: small - from 0.1 mm to 0.2 mm in size, large - from 0.21 mm to 0.5 mm in size.

 3. They perform etching of the disks according to the established technology.

 4. A similar inspection, as before etching, determines the disappearance (etching) of the prints, taking into account their classification and size.

 5. Prepare control samples with prints having dimensions that are extremely permissible for etching.

 6. Cut down an industrial batch of discs with control of prints on control samples.

 EXAMPLE. Disks were made from a strip 0.4 mm thick of molybdenum grade MCH, supplied in accordance with TU 48-315-89. The prints were fixed (sketched), as well as scratches (to compare the etching effect). Etching was performed according to the technology described at the beginning of the application. Again, the effect of the disappearance (etching) of the prints was examined and evaluated. The results are shown in tables 1-3.

 It was found that small prints disappear during etching, large ones (point and linear) partially disappear. Etching was performed in laboratory or industrial conditions, inspection in laboratory, using a MBS-2 microscope.

 The technical result consists in reducing disc rejection, increasing the yield of useful parts, reducing the consumption of expensive scarce molybdenum. The method is implemented in the EEC.

Claims (1)

A method of manufacturing disks from a molybdenum strip, including cutting down the disks, controlling their surface defects and subsequently removing said surface defects by etching, characterized in that they control surface defects of the disks by the fingerprints of the rolls from the samples, the samples being obtained by making an experimental batch of disks, determining on disks of this batch of sizes of roll prints to be removed by etching, and preparation of control discs with prints having these sizes and size limits for the removal by etching, and after said control rejection produce discs having rollers prints with dimensions exceeding the limits.

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