Post by khatunejannat on Feb 15, 2024 0:21:42 GMT -5
The history of machining is relatively short; In fact, it did not begin to develop until the industrial revolution in the 19th century, but it took many more years to consolidate . This development would not have been possible without the evolution that cutting tools underwent. At the dawn of machining, the tools were just a little harder than the materials they machined, which were the ones that offered the least problems (wrought iron, bronze and gray cast iron). Tools made of tempered carbon steel were not suitable for machining alloy steels , and it was not until the appearance of Mushet steel that this changed (Robert Mushet experimented with manganese and tungsten in steel). Several years after its discovery it was seen that this material had much greater resistance to wear and the tools used had to be resharpened less frequently. In fact, more than the greater cutting capacity, the main advantage lay in its ability to withstand higher cutting temperatures .
The cutting speed ranged around 10 meters/minute. In 1900, when Fredrick Taylor made a demonstration at the Paris International Exhibition turning a piece of mild steel with a tool that at Syria Email List high cutting speeds and feeds (for that time) obtained blue chips and remained sharp even when red. The cutting speed suddenly stood at 40 meters/minute. High speed steels (HSS) Taylor, along with Maunsel White, moved from using Mushet steels by adding elements in the alloy such as chromium and tungsten, increasing the content of heat-resistant hard carbides based on tungsten and the temperature of use. By not losing hardness up to 600º C, thanks above all to its high tungsten content, it makes machining at high cutting speeds possible. These tools were progressively improved, and in the 1930s extra-fast steels (HSS-E) appeared, with cutting speeds around 70 meters/minute. Although they have been largely surpassed by new tool materials, they are still in significant use.
HSS face milling cutter (UOP IZAR group) Hard metal (“WIDIA”) In 1926, the German company Krupp discovered cemented carbide , presenting it at the Leipzig fair in 1927 under the name Widia. In the 1930s, its practical application as a cutting material began, with 90% very hard carbides (initially tungsten carbide) and cobalt as a binder. The pulverized material is pressed and sintered, then joining with the binder). At that time, small plates of cemented carbide were welded onto tool handles to form the cutting tool. However, it was not until World War II that there were powerful machines and sufficient demand to manufacture weapons and transport elements. However, rapid breakage of the cutting edge still occurred, problems that were solved with the addition of titanium, tantalum and niobium carbides, as additional elements of tungsten carbide, in different phases. Improvements were also achieved in the toughness of the tool, for the most unfavorable conditions (at the cost of lower hardness.
The cutting speed ranged around 10 meters/minute. In 1900, when Fredrick Taylor made a demonstration at the Paris International Exhibition turning a piece of mild steel with a tool that at Syria Email List high cutting speeds and feeds (for that time) obtained blue chips and remained sharp even when red. The cutting speed suddenly stood at 40 meters/minute. High speed steels (HSS) Taylor, along with Maunsel White, moved from using Mushet steels by adding elements in the alloy such as chromium and tungsten, increasing the content of heat-resistant hard carbides based on tungsten and the temperature of use. By not losing hardness up to 600º C, thanks above all to its high tungsten content, it makes machining at high cutting speeds possible. These tools were progressively improved, and in the 1930s extra-fast steels (HSS-E) appeared, with cutting speeds around 70 meters/minute. Although they have been largely surpassed by new tool materials, they are still in significant use.
HSS face milling cutter (UOP IZAR group) Hard metal (“WIDIA”) In 1926, the German company Krupp discovered cemented carbide , presenting it at the Leipzig fair in 1927 under the name Widia. In the 1930s, its practical application as a cutting material began, with 90% very hard carbides (initially tungsten carbide) and cobalt as a binder. The pulverized material is pressed and sintered, then joining with the binder). At that time, small plates of cemented carbide were welded onto tool handles to form the cutting tool. However, it was not until World War II that there were powerful machines and sufficient demand to manufacture weapons and transport elements. However, rapid breakage of the cutting edge still occurred, problems that were solved with the addition of titanium, tantalum and niobium carbides, as additional elements of tungsten carbide, in different phases. Improvements were also achieved in the toughness of the tool, for the most unfavorable conditions (at the cost of lower hardness.