Tungsten Steel Alloy Button PM Sintered Parts

Product Introduction

Sintering process

For steels containing tungsten, such as high-speed steel and some hot work die steels, tungsten in the steel can significantly improve the hardness and heat resistance of the steel, but the toughness will drop sharply.

The main component of cemented carbide is tungsten carbide, so it is also called tungsten steel.

Tungsten steel belongs to cemented carbide, also known as tungsten titanium alloy. The hardness can reach HRB89 to 95. Because of this, tungsten steel products (commonly tungsten steel watches), Tungsten steel alloy button PM sintered parts are not easy to be worn.

It is often used on lathe tools, impact drill bits, glass cutter heads, and tile cutters. It is hard and not afraid of annealing, but brittle. Belongs to the list of rare metals.

Component structure

The sintering of tungsten steel is pressing the powder into a billet, then heating it into a sintering furnace to a certain temperature (sintering temperature), keeping it for a certain time (holding time), and then cooling it down to obtain the tungsten steel material with the required properties.

Four basic stages of the tungsten steel sintering process

1. In the stage of removing the forming agent and pre-sintering, the sintered body undergoes the following changes at this stage:

Removal of molding agent, as the temperature rises in the initial stage of sintering, the molding agent gradually decomposes or vaporizes, and the sintered body is excluded. The type, quantity, and sintering process vary.

The oxides on the surface of the powder are reduced. At the sintering temperature, hydrogen can reduce the oxides of cobalt and tungsten. If the forming agent is removed and sintered in a vacuum, the carbon-oxygen reaction is not strong. The contact stress between powder particles is gradually eliminated, the bonded metal powder begins to recover and recrystallize, surface diffusion begins to occur, and the compact strength increases.

2. Solid phase sintering stage (800°C--eutectic temperature)

At the temperature before the liquid phase appears, in addition to continuing the process that occurred in the previous stage, the solid phase reaction and diffusion intensify, the plastic flow is enhanced, and the sintered body shrinks significantly.

3. Liquid phase sintering stage (eutectic temperature - sintering temperature)

When the liquid phase appears in the sintered body, the shrinkage is completed quickly, followed by crystallization transformation to form the basic structure and structure of the alloy.

4. Cooling stage (sintering temperature - room temperature)

At this stage, the structure and phase composition of tungsten steel change with different cooling conditions. This feature can heat treat tungsten steel to improve its physical and mechanical properties.

Metal Injection Molding Process

Detection Systems