Although tungsten alloy and hard alloy are transition metal tungsten alloy products, can be used in aerospace, aviation and navigation fields, but due to the addition of elements, composition ratio, production technology, the performance and use of the two are also different.
First, definition
Tungsten alloy, also known as high specific gravity alloy, is a kind of tungsten powder as the main raw material, nickel, iron, copper and other elements as auxiliary materials of the alloy. Tungsten content is generally between 85% and 99%.
Hard alloy, also known as tungsten steel, is a kind of refractory metal carbide such as tungsten carbide as the main component, with cobalt, nickel, molybdenum and other elements as the binder of the alloy. Binder content is generally between 10% and 20%.
Second, performance
High specific gravity alloy has high melting point, density, strength and hardness, good plasticity, heat resistance, corrosion resistance, impact resistance, oxidation resistance and shielding effect.
Tungsten steel also has similar properties with tungsten alloy, but its thermal hardness and wear resistance advantages are very obvious, mainly reflected in the 500℃ basically unchanged, still has a high hardness at 1000℃. However, its brittleness is very large, so the cutting.
Three, production technology
Preparation steps of tungsten alloy: 1) Material preparation: tungsten compounds such as ammonium tungstate, auxiliary materials such as nickel, iron, copper and other elements or compounds; 2) Powder making: there are spray drying method and mechanical alloying method; 3) Forming: After mixing tungsten powder with forming agent, extruded and injected into the forming machine, it can prepare parts with complex shapes; 4) Sintering: the microstructure of the alloy after sintering treatment is more uniform and the comprehensive performance is higher.
Preparation steps of hard alloy: 1) Remove surface impurities of tungsten carbide particles and cobalt particles; 2) The above materials were crushed and mixed with a mixer. After grinding, the alloy powder was obtained; 3) The alloy powder is added into the extrusion mold and extruded to obtain the cemented carbide precursor, which is mixed with liquid and added with binder to form the metal powder slurry; 4) The slurry through the spray granulator into powder, after sintering and heat treatment can be.
Four, use
Tungsten alloy is mainly used as counterweight parts (such as automobile crankshaft, mobile phone vibrator, etc.), shielding parts (such as medical collimator, shielding tank, etc.), heat shield (such as vacuum furnace heat shield, etc.), jewelry (such as necklace, ring, etc.) and military products (such as bullets, armor-piercing bullets, warheads, etc.).
Hard alloy is mainly used as hardware molds (such as wire drawing molds, bolt molds, nut molds, etc.), tools (such as turning tools, milling knives, planer knives, etc.), ornaments (such as rings, pendants, bracelets, earrings, etc.), rock drilling tools, mining tools, drilling tools, rocket nozzles.
