{"id":1307,"date":"2018-01-09T16:46:15","date_gmt":"2018-01-09T15:46:15","guid":{"rendered":"https:\/\/www.nashirahardmetals.com\/?page_id=1307"},"modified":"2021-01-12T14:13:51","modified_gmt":"2021-01-12T13:13:51","slug":"what-is-hardmetal","status":"publish","type":"page","link":"https:\/\/www.nashira-hm.it\/en\/what-is-hardmetal\/","title":{"rendered":"What is Hardmetal?"},"content":{"rendered":"

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What is Hardmetal?<\/h2>\n

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Carbide (also known as Widia<\/strong><\/a>, Cemented Carbide or Tungsten Carbide) is a material used in mechanical machining consisting of hard Tungsten Carbide particles incorporated in a metal matrix (often Cobalt). Carbide is produced thanks to the sintering process; in other words, the fine powders of the components are mixed, pressed and then heated. Therefore, the pressure is kept high, so that the powder granules come together to form a single piece. This means that hard metals are not real metals but carbides bound by a metal. About 50% of the cemented carbides are produced with Tungsten Carbide (70-95%) and Cobalt.[\/vc_column_text][\/vc_column][vc_column width=”1\/2″][vc_single_image image=”3312″ img_size=”large” alignment=”right”][\/vc_column][\/vc_row]<\/p>\n

Tungsten carbide <\/span><\/span><\/h2>\n

It looks like a dark gray powder. Its molecular formula is WC. It is a very hard material, which ranks around 9 on the Mohs scale and around 2600 on the Vickers scale. It has a density<\/a><\/strong> of 15.63 g \/ cm3 as per the metal density table, so it requires too high melting or sintering temperatures to be used pure. For practical use it is combined with transition metals such as cobalt or nickel. <\/span><\/span><\/p>\n

Cobalt <\/span><\/span><\/h2>\n

It is an excellent bond for hard metal. To improve the transverse breaking strength, hardness and density of the cemented carbide, a cobalt powder with very fine particles is used. <\/span><\/span><\/p>\n

Cemented Tungsten Carbide (HardMetal) <\/span><\/span><\/h2>\n

It has a high degree of hardness<\/strong><\/a>; and a high resistance to pressure, deformation and high temperatures. These are very useful physical characteristics in metal cutting applications. Widia tungsten carbide allows a long life to tools which, if made with other materials, would soon wear out. For more information, see the page on the technical characteristics of hard metal. <\/span><\/span><\/p>\n

Hard metal producers <\/span><\/span><\/h2>\n

Among the hard metal producers is Nashira Hardmetals, a company with a long experience and committed to research and development. At Nashira, we offer many different grades of carbide to meet the requirements of every project and application. Contact us for more information <\/span><\/span><\/p>\n

The production of hardmetal in Nashira <\/span><\/span><\/h2>\n

Since 1999 in Nashira we have been manufacturing components and semi-finished products in hard metal.<\/span><\/span><\/p>\n

Raw materials<\/span><\/span><\/h3>\n

First we buy the raw materials: carbide, tungsten and cobalt powders. Their particles can have different characteristics and a degree of purity, depending on the process by which they are obtained. The combination of tungsten carbide and cobalt allows for the creation of a highly hard and wear-resistant alloy. Then we move on to the actual production. <\/span><\/span><\/p>\n

Mixing of powders <\/span><\/span><\/h3>\n

The production starts from the mixing of the powders. This takes place in cylindrical or double cone drums; or in screw or paddle mixers. Depending on the use for which the hardmetal is intended, a particular compound is required. For example, using 10% cobalt we obtain a hardness of about 90 HRA, suitable for making semi-finished products for companies that produce finished tools for working wood. Instead, an 8% cobalt mixture is suitable for instruments dedicated to the metal sector. <\/span><\/span><\/p>\n

Compaction, pressing and shaping <\/span><\/span><\/h3>\n

When the mix is \u200b\u200bready, we proceed to compaction. In this phase a high pressure value is applied to the powder, to reduce the spaces between the particles and obtain the desired shape. The most common method of compaction is pressing. In this case, two opposing motion punches compress the powder contained in a mold. It is possible to produce blocks of semi-finished products in the shapes requested by the customer; or you can press the powder into molds with defined geometry. Shaping and cutting follow. <\/span><\/span><\/p>\n

The blocks are machined by machine tools to obtain the final shape and dimensions are increased by about 20%, to compensate for the effect of the shrinkage of the material that will occur during sintering. The obtained product is called green compact; this means that the process is not yet concluded. In fact, each particle has its own surface. And the material still lacks strength and hardness.<\/span><\/span><\/p>\n

Hardmetal Sintering process<\/span><\/span><\/h3>\n

At the end the products are subjected to the sintering process. It is a heat treatment that welds the particles into an indivisible compound: the sintered metal. Thanks to the contribution of heat, porosities are eliminated and junctions and bridges are created between the particles; therefore the total surface of the material is reduced. <\/span><\/span><\/p>\n

Usually in sintering the temperature is equal to 1400-1500 \u00b0 C. However it must be below the melting point. It is also defined as a function of the percentage of cobalt used. As a result of the sintering, the ceramic-metallic material called cemented carbide, hard metal or widia is obtained.<\/span><\/span><\/p>\n

Metal sintering: alternative technologies <\/span><\/span><\/h3>\n

There are other technologies to obtain hard metal, also called cemented carbide, sintered widia metal or carboloy.<\/span><\/span><\/p>\n

Isostatic compaction <\/span><\/span><\/h2>\n

Isostatic compaction is among the techniques used in Nashira. In this case the pressure is exerted evenly by means of a liquid. The operation can take place: <\/span><\/span><\/p>\n