W18Cr4V 
 1 W18Cr4v, commonly used tungsten as a high-speed steel, it belongs to ledeburite steel, high-speed steel is the most long-lasting one. Like other high-speed steel, often referred to as "white steel", "front steel" or "wind of steel" (air to quench). 3 Chemical composition: carbon content of 0.7 7 - 0.8%, the amount of tungsten 17.5 - 19% chromium content 3.80 - 4.4% vanadium content 1.0 - 1.4%, less than 0.4% silicon content, including less than 0.4% manganese, molybdenum content is less than 0.3%. 8 red hardness: 8 cutting temperature 540 degrees, hardness HRC66 9 cutting can maintain the temperature 600 degrees, hardness HRC63 5 can maintain the advantages: versatility, sophisticated technology. 5 Disadvantages: carbide segregation serious, thermoplastic low, tool hardness and red hardness can not meet the special hardware and special processing tough materials. Alloying element content and high cost. 8 cutting speed: 80 m / sec (600 degrees Celsius). 9 Usage: shape of small complex tool. 6 W18Cr4V the nature and processing of steel Edit this paragraph W18Cr4V steel composition characterized by 
 In steel, carbon mainly chromium, tungsten, molybdenum and vanadium (carbide forming elements), etc. to form carbide, in order to improve hardness, wear resistance and red hardness. Tungsten is to improve the red hardness of the main elements that form carbides in the steel. Heating, part of the carbon dissolved in austenite after quenching form contains a lot of tungsten and other alloying elements, the stability of a high tempered martensite. In tempering, the part of the tungsten carbide in the form of dispersion to precipitate, causing secondary hardening. When heated, the undissolved carbides play a role in preventing austenite grain growth. Vanadium can significantly improve high-speed steel red hardness, hardness and wear resistance. The formation of vanadium carbides in the heating, some integration into the austenite, tempering with a small particle dispersion precipitation, resulting in secondary hardening and improve red hardness of steel. Chromium in high-speed steel is to increase its hardenability while improving anti-oxidation and decarbonization of steel and corrosion resistance. Cobalt can also significantly increase the red hardness and hardness of steel. 
 W18Cr4V steel structure 
 The cast includes W18Cr4V was bone-like tissue, and martensite or carbide sheet troostite arranged ledeburite white and black organizations (δ segregation) and the white tissue (martensite and retained austenite) . High-speed steel cast structure and chemical composition in particular, uneven, and the heat treatment does not change, so the pressure must be processed, the coarse eutectic carbides break, and make it uniform, and then use to manufacture a variety of cutting tools and mold 
 W18Cr4V forging process 
 High-speed steel when heated are prone to over-burning, forging close to this temperature range is prone to fragmentation, should strictly control the heating temperature. 1). W18Cr4V forging temperature range is a high alloy steel, which is characterized by slow heating, forging a narrow temperature range. Before forging temperature of 1100 ~ 1150 ° C, the final forging temperature of 900 ~ 950 ° C. 2) the heating time to determine the thermal conductivity of steel W18Cr4V poor, it generally takes the heating section. Low-temperature heating temperature of 800 ~ 900 ° C, heating time is generally based on 1mi n / mm calculations. Quickly when the heating temperature, heating time is generally at 0. 5mi n / mm calculations. Heating, in order to prevent overheating or burnt, to strictly control the maximum temperature. At the same time, the furnace billet furnace to be installed right amount, but also to keep turning, so that it evenly inside and outside temperature. 
 Forging organization 
 W18Cr4V heat treatment process 
 Heat treatment process for the pre-treatment is annealing temperature of 870 to 880 degrees, heat 2 to 3 hours, then 800 a preheated 840 degrees, from 1270 a 1280 grading quenching temperature of 580 a 620 grade, then 560 degrees three times tempering, tempering heat 1 hour. W18Cr4V contain large amounts of alloying elements: plastic is poor, poor thermal conductivity in the fast heating of the thermal stress to the deformation of cracking, so in 1270 a heated to quenching temperature of 800 degrees 1280 a 840 warm-up, those of complex shape, but also an increase in a preheated 500 to 650. V, W, etc. play a major increase from the red rigid elements only to be dissolved under high temperature, but too high a temperature will make the coarse grains, and the W, A, alloying elements are reduced, making the eutectic eutectoid temperature increase, chose 1270 a 1280 degree. direct air-cooled, precipitation of secondary carbides will be analyzed, thereby reducing the red hardness of steel. quenched organization for the M + carbide ten residues A (up to 30%) in 550 a 570 degree temper caused precipitation of secondary hardening WC, A decomposition analysis of C, lower alloy element content, so that Ms rise, resulting in secondary quenching, a tempering, and 15% of the residual A, second tempering residual A3% to 5%, three tempering, only 1% to 2%, M + eventually have to temper the organization a very small amount of residual carbide ten