Goes to Rio tungsten steel 
 Introduction tungsten steel, such as high-speed steel and hot work die steel, steel containing tungsten steel hardness and heat resistance of a significantly improved, but the toughness will be a sharp decline. 

 The main ingredient in the carbide to tungsten carbide and cobalt, and other accounted for 99% of all ingredients and 1% other metals, also known as tungsten steel 

 Tungsten steel are carbide, also known as tungsten titanium. Hardness can reach HRB89 95 For this reason, tungsten steel products (common tungsten steel watches), with easy to wear, hard not afraid of annealing, but brittle characteristics. 
 Commonly used in high-precision machining, precision cutting tool material, a rare metal out. 
 Composition and structure of 
 Sintering of tungsten steel is powder pressed into billets, and then into the sintering furnace heated to a certain temperature (sintering temperature), and to maintain a certain amount of time (holding time), and then cooled down, resulting in the desired properties of tungsten steel. 

 Tungsten steel sintering process can be divided into four basic stages: 

 1: Removal of forming agents and burn-in phase, at this stage sintered body changes as follows: 

 Forming agent, the removal of the initial stage of sintering as the temperature rises, forming agent, the gradual decomposition or vaporization, excluding sintered at the same time, forming agent is more or less to the sintered body by carbon, increasing the amount of carbon with forming agent type, quantity, and the sintering process of the different changes. 

 Powder surface oxide reduction, sintering temperature, the hydrogen reduction of cobalt and tungsten oxide, vacuum forming agent removal and sintering, carbon and oxygen reaction is not strong. The contact stress between the powder particles to gradually eliminate the bonding metal powder to produce recovery and recrystallization, surface diffusion began briquette strength improved. 

 2: solid-phase sintering stage (800 ° C - the eutectic temperature) 

 Liquid phase before the temperature, in addition to the last phase of the process, solid-phase reaction and diffusion intensified, enhanced plastic flow, sintered apparent contraction. 

 3: stage of liquid phase sintering (eutectic temperature - sintering temperature) 

 When the sintered body appears liquid contraction to be completed soon, and then produce the crystalline transition, the formation of the basic organization and structure of the alloy. 

 4: cooling phase (sintering temperature - room temperature) 

 At this stage, the organization and the phase composition of the tungsten steel with different cooling conditions to produce some of the changes, you can use this feature to be heat treated to improve their physical and mechanical properties of tungsten steel.