Tool steels carbon

MARTENSITE. The chief constituent of hardened carbon tool steels. It is a solution of carbon or FeiC in /(-iron. or and exceedingly line-grained or-iron with carbon or l cmolecular dispersion. Carbon content up to I easily obtained bv quenching small bodies of liypereutectoid steel in cold water more difficult to obtain in low-carhun steels. 

High Speed Steels. Toward the latter part of the nineteenth century, a new he at-treatment technique for tool steels was developed in the United States (3,17) that enabled increased metal removal rates and cutting speeds. This material was termed high speed steel (HSS) because it nearly doubled the then maximum cutting speeds of carbon—low alloy steels. Cemented carbides and ceramics have since surpassed the cutting speed capabiUties of HSS by 5—15 times. 

A hard, mst-resistant shaft of at least 0.25 micrometer finish is usually required. Common shaft surfaces are hardened tool steel, chrome plate, high strength bronze, and carbide and ceramic overlays. Test results over a broad speed range from 0.05 to 47 m/s (10 to 9200 fpm) iadicate that a coefficient of friction of 0.16—0.20 and a wear factor of 14 X 10 m /N(70x 10 ° in. min/ft-lb-h) are typical for dry operation of weU appHed grades of carbon—graphite (29). 

The Dilex Process utilises a molten lead bath as transfer medium and is applicable to diflfusion coatings of Cr, Al, Ti, Mo, Ni and Co. Finally, a Japanese fused borate bath process produces carbide coatings (Cr, V, Nb or Ta) on carbon and tool steels. The coatings are wear and corrosion resistant. The TD Process uses this technique. 

If acetonitrile (CH3CN) is used as a carbon and nitrogen source, the deposition temperature is greatly reduced and the process can be used to coat tool steel The reaction is carried out at low pressure... 

The choice of a particular plastic includes numerous types. It is easier to cope with this multitude of product if plastics are considered as a category of materials—like metals—encompassing some 40 plus distinct families. Each family in turn is composed of many individual types. Just as the family of steels includes carbon steels, tool steels, stainless, etc., nylon includes 6, 6/6, 6/10, filled or unfilled, etc., each type having distinct properties. 

Comparison of Brinell, Vickers, Knoop, Rockwell and Shore hardness for carbon and low-alloy steels and roughly for all constructional and tool steels in various states of thermal processing... 

Creates a diffused carbon, titanium, and TIC case. Base ineials are alloy and tool steels Process temperature range is 900-1010 C (1650- 1X50"F). 

Niobium in Tool Steels. In the matrix method of tool-steel development, the composition of the heat-treated matrix determines the steel s initial composition. Carbide volume-fraction requirements then are calculated, based upon historical data, and the carbon content is adjusted accordingly. This approach has been used to design new steels in which niobium is substituted for all or part of the vanadium present as carbides in the heat-treated material. Niobium provides dispersion hardening and grain refinement, and forms carbides that are as hard as vanadium, tungsten, and molybdenum carbides. 

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