CC BY
28
ISSN 1680-9165. №3-4, 2015 r.
UDC 621.9.02
V. Y. Kotelnikova1, A. P. Umarova1, A. A. Mikhailova1, D. A. Iskakova2
'students, 2senior lecturer, S. Toraighyrov Pavlodar State University named after, Pavlodar.
METAL cUTTING TooL
In this paper the authors give an analysis of the distinctive features of the types of metal cutting tools and their characterization.
Key words: tool, cutting, milling cutter, processing.
Metal cutting tool is production tool for changing the shape and dimensions of metal blanks by removing part of the material in the form of metal chips with the aim of producing finished or semi-finished part.
Figure 1 - Metal cutting tool 1 - clamped-tip cutting tool; 2 - twist drill; 3 - multiflute drill with cone shank, equipped by inserts; 4 - shell-type face mill inserted blades, equipped by hard alloys; 5 - machine insert reamer; 6 - die; 7 - circular-type die head; 8 - hob cutter; 9 - spline broach; 10 - tool head for processing of bevel wheel; 11 - tap; 12 - gear-shaping cutter with spiral teethes
The difference is made between machine and hand tools. The main parts of the metal cutting tool are the working part, which may consist of cutting and gauging parts, and the mounting part. The cutting unit of the metal cutting tool is the part that directly penetrates the metal of the blank and cuts away part of it. The cutting unit consists of number of the structural elements: one or more blades; channels for guiding the removal of the chips; chip breakers; chip curlers; elements, which are basic elements in the manufacture, testing, refrigerant of tool; the channels for the supply of lubricating-cooling fluid. The
purpose of the gauging unit of the metal cutting part is the restoration of the cutting unit during sharpening, final shaping of the surface being machined and guidance of the metal cutting tool during its operation. The mounting unit of the metal cutting tool is used to set the tool in the machine in strictly determined position or for manual holding of the tool and it must resist the forces arising during the process of cutting. The mounting unit may be designed in the form of brackets, shanks or it may have an opening for mounting on mandrels. Depending on the technological purpose the lathe metal cutting tools are divided into following subgroup: cutting tools, milling cutters, broaches, gear-cutting tool, thread-cutting tools, tools for machining of openings and abrasive and diamond tools. Cutting tools are used in turning machines, turret machines, vertical turning machines, boring, planing, slotting and other machines (with the exception of thread-cutting and gear-cutting tools) for turning, boring openings, shaping flat and profiled surfaces and cutting channels. Milling cutters are multifluted rotary tools that are used in turning lathes for machining flat and profiled surfaces, as well as for cutting blanks apart. Broaches are multifluted tools for machining smooth and shaped internal and external surfaces. Openings are bored and machined by means of drills, countersinks, counterbores, reamers, spotfacers, boring bars, and combination tools, which are used in boring, turning, turret, drilling, and jig-boring machines. Gear-cutting tool is intended for cutting and milling of the teeth on gears, gear racks, and worm gears. Thread-cutting tool is used for cutting and milling interior and exterior threads. The list of the thread-cutting tools also includes thread tools and cutters, taps, dies and others. Among the abrasive tools are grinding wheels and bricks, honing heads, and emery cloths, which are used for grinding, polishing, and lapping parts, as well as for sharpening tools. The diamond tool includes disks, cutters and milling cutters with diamond blades.
The hand tools include chisels, files, broach files, hacksaws, scrapers and others, which are used without the metal cutting machinery. The hand machines with electric, hydraulic, or pneumatic drive that use hand tools as the working members have come into widespread use. The properties of the processing material, the lubricating and cooling fluid and the rigidity of the system formed by the attachment, instrument and part are taken into account in selecting the shape and leap angle of metal cutting tools, which determine their durability, productivity, economy and the quality of milling (See cutting-tool geometry). The cutting capacity of metal cutting tool is determined by the properties of the material from which the cutting part is made. The most important indicator is the red hardness of the material. The following main groups of materials are used: tool steels (carbon, highspeed and alloy steels), hard alloys and super hard powdered ceramic materials. Tools made from carbon steels (red hardness - 200°-250°C) are used for milling common materials at moderate cutting speeds. High-speed steels alloyed with tungsten make possible an increase in the cutting rate by a factor of 2-4. Blanks made from heat-resistant alloys and steels of increased hardness are milled with tools made from steel with increased content of vanadium, cobalt and molybdenum and with decreased tungsten content. The red hardness of these materials may be as high as 600°-620°C, but their brittleness also increases. Hard alloys, the most modern and widespread materials for metal cutting tools, are replacing the tool steels (except in cases where intermittent turning and profile
ISSN 1680-9165. №3-4, 2015 г.
milling of great depth are required). They have a red hardness of 750°-900°C and have great wear resistance. Hard alloys for metal cutting tools are produced in the form of plates of various shapes and dimensions. Small one-piece hard-alloy metal cutting tools are also produced. Metal-cutting tools with cutting parts reinforced by powdered ceramic plates produced from an aluminum oxide base with added molybdenum and chromium have even higher red hardness (1100°-1200°C) and wear resistance. However, the use of powdered ceramics is limited by their low plasticity and high brittleness. The use of super hard materials, such as natural and synthetic diamonds and cubic boron nitride and others (for grinding and sharpening of cutting tools is highly promising). The technological parameters of the metal cutting tool depends on the depth of cutting, the feed rate and the cutting speed (See metal cutting). The width of the worn area on the relief surface of the tool, taking into account the type of tool, the required precision of milling and the degree of surface roughness, is an accepted criterion for wear of the cutting portion of the metal cutting tool. The wear resistance of the metal cutting tools is determined by the duration of actual cutting (in minutes) between sharpening. The main requirement for the metal cutting tool - high output for a given degree of surface roughness and milling precision is satisfied by fulfilling the conditions with respect to manufacturing tolerances, deviations from the geometric parameters, hardness of the cutting elements and external appearance. The construction of the metal cutting tools must provide for repeated sharpening, as well as reliable and rapid mounting. Special elements for mounting metal cutting tools, such as bit holders, conical openings, and mandrels, are taken into account in the design of metal cutting equipment.
Machinery equipment of the PSU
The machine-tools of various industrial purposes (Б-103, Б-104, Б-105, Б-106) are being a part of the job training workshops. There are screw-cutting, milling, drilling, planning, grinding, gear-hobbing, gear-shaping and gear planning machines.
1 The tools for turning machines: dies, taps, cutting tools (straight-turning tools, side-facing tools, offset tools, cutting-off tools, boring tools, thread tools, clamped-on cutters, facade cutters);
2 The tools for milling machines: face mill (interlocking side mill, solid mill and hollow mill), end-mill type gear cutters, keyway milling cutters, disk cutters, grooving cutters, gear-milling cutters, T-slot cutters, double-angle cutters, concave form cutters and semi convex cutters;
3 The tools for drilling machines: drills (twist-drill and V-drill), countersinks, taper reamers;
4 The tools for gear-hobbing machines: worn gear cutters (for gear cutting);
5 The tools for gear-shaping machines: shank-type cutters and deep counterbores-type cutters;
LIST OF REFERENCES
1 Металлорежущий инструмент, научное издание Г. И. Грановский. - 2 изд., М., 1954. - 142 с.
2 Режущий инструмент : учебник для студентов высших учебных заведений / Д. В. Кожевников, В. А. Гречишников, С. В. Кирсанов. научное издание / С. В. Кирсанова. - 3-е изд. - «Машиностроение», 2007 - 526 с.
Material received on 15.12.2015.
В. Ю. Котельникова, А. П. Умарова, А. А. Михайлова, Д. А. Искакова Металл кесетш к^ралдар
С. ТораЙFыров атындаFы Павлодар мемлекетпк университет^ к. Павлодар.
Материал 15.12.2015 баспаFа тYстi
В. Ю. Котельникова, А. П. Умарова, А. А. Михайлова, Д. А. Искакова Металлорежущие инструменты
Павлодарский государственный университет имени С. Торайгырова, г. Павлодар. Материал поступил в редакцию 15.12.2015.
Осы бапта автор металл кесетт куралдардыц ерекше взгешшктер анализт жэне олардыц сиппаттамасы бередi.
В настоящей статье авторы дают анализ отличительных особенностей видов металлорежущих инструментов и их характеристику.
УДК 621.182.13:621.13(574.25) В. А. Калискаров
Павлодарский государственный университет имени С. Торайгырова, г. Павлодар
ПРОБЛЕМЫ ЭКСПЛУАТАЦИИ ПИТАТЕЛЬНЫХ НАСОСОВ ЭНЕРГОБЛОКОВ МОЩНОСТЬЮ 500 МВТ ЭКИБАСТУЗСКОЙ ГРЭС-1 ИМ. Б. НУРЖАНОВА И МЕРОПРИЯТИЯ, РЕАЛИЗОВАННЫЕ ПРИ РЕКОНСТРУКЦИИ ПИТАТЕЛЬНЫХ НАСОСОВ ПН-1500-350-3 И ПН-1500-350-4
В данной статье представлены исследования причин аварийных ситуаций питательных насосов энергоблоков Экибастузской ГРЭС-1.
Ключевые слова: насос, энергоблок, ГРЭС—1, Экибастуз, аварийная ситуация.
В настоящее время на паротурбинных блоках мощностью 500 МВт в качестве питательных насосов наряду с другими применяются насосы типа ПН-1500-350 и ПН-1500-350-1. Длительный период эксплуатации питательных насосов обнаружен у них ряд недостатков. Для их устранения заводом-изготовителем была осуществлена доработка и модернизация насосов. Эти насосы получили обозначения ПН-1500-350-3 (рисунок 1) и ПН-1500-350-4 (рисунок 2).
