{"id":29385,"date":"2021-02-28T21:11:21","date_gmt":"2021-02-28T21:11:21","guid":{"rendered":"http:\/\/sitepourvtc.com\/?page_id=29385"},"modified":"2023-08-22T07:26:48","modified_gmt":"2023-08-22T07:26:48","slug":"high-speed-steel-hss","status":"publish","type":"page","link":"https:\/\/sitepourvtc.com\/nuclear-engineering\/metals-what-are-metals\/steels-properties-of-steels\/high-speed-steel-hss\/","title":{"rendered":"High-speed Steel – HSS"},"content":{"rendered":"
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\"High<\/a>
High-speed steel (HSS) is a tool steel with high hardness, wear resistance, and heat resistance. High-speed steel is often used in power-saw blades and drill bits.<\/figcaption><\/figure>\n

High-speed steels<\/strong>, abbreviated as HSS, are a specialized class of tool steels<\/a> named primarily for their ability to machine and cut materials<\/strong> at high speeds<\/strong> (high hot hardness). It is often used in power-saw blades and drill bits. High-speed steel<\/strong> is superior to the older high-carbon steel<\/a> tools in that it can withstand higher temperatures without losing its temper (hardness). High-speed steels<\/strong> are complex iron-base alloys of carbon, chromium, vanadium, molybdenum, tungsten, or combinations thereof. An appropriate hardening response must be provided in heat treatment to achieve good cutting performance from HSS.<\/p>\n

Central to the performance of high-speed steels is the hardening response achieved during the heat treatment process. Alloying elements are introduced in quantities given by the intended application and their function in the heat treatment process, whether to increase the solidus temperature or inhibit the growth of secondary hardening precipitates, enabling higher operating temperature.<\/p>\n

High-speed Steel \u2013 AISI M2<\/h2>\n

For example, molybdenum high-speed steel<\/strong> \u2013 AISI M2 is the \u201cstandard\u201d and most widely used industrial HSS. According to the AISI classification system, molybdenum high-speed steels are designated as Group M steels. M2 HSS has small and evenly distributed carbides giving high wear resistance, though its decarburization sensitivity is a little bit high. It is usually used to manufacture various tools, such as drill bits, taps, and reamers.<\/p>\n

The carbon and alloy contents are balanced at sufficient levels to provide a high attainable hardening response, excellent wear resistance, high resistance to the softening effects of elevated temperature, and good toughness for effective use in industrial cutting applications. Titanium nitride<\/strong> (an extremely hard ceramic material) or titanium carbide coatings can be used in the tools made of this kind of steel through a physical vapor deposition process to improve the performance and life span of the tool. TiN has a Vickers hardness of 1800\u20132100 and a metallic gold color.<\/p>\n

\"M2<\/a><\/p>\n

Alloying Agents in High-speed Steels<\/h2>\n
\"High-speed<\/a>
High-speed steel – M8<\/figcaption><\/figure>\n

Pure iron is too soft to be used for the purpose of a structure. Still, adding small quantities of other elements (carbon, manganese, or silicon, for instance) greatly increases its mechanical strength. The synergistic effect of alloying elements and heat treatment produces various microstructures and properties. The four major alloying elements that form carbides in high-speed steels are tungsten, chromium, vanadium, and molybdenum. These alloying elements combine with carbon to form hard and wear-resistant carbide compounds. The microstructure of high-speed steels<\/strong> consists of a martensitic matrix with a dispersion of two sets of carbides. These carbides are usually known as primary and secondary carbides. Primary carbides are those carbides formed during the solidification of the steel, and secondary carbides are those formed during secondary hardening heat-treatment of the steels.<\/p>\n