Introduction to Powder Metallurgy Process for Stellite Alloys Parts

Powder metallurgy is a processing method in which metal powders are used as raw materials and various products are made by pressing and sintering. The powder metallurgy process consists of three major steps. First, the main constituent material is broken down into powder consisting of a large number of fine particles; Then, the powder is loaded into the mold cavity and a certain pressure is applied to form the desired shape and size; Finally, the compact is sintered.

The important properties of metal powder are:

• Particle shape: the shape of the powder particles is related to the manufacturing method. The more irregular the powder is, the greater the strength of the compact is.
• Fineness: refers to the size of the powder particles. The size of the powder particles is checked by a sieve. The size distribution of the particles is determined by a classification method. Finer powders have better sinterability.
• Particle size distribution: refers to the number of particles per level.
• Flowability: refers to the situation where the powder can flow through and fill the cavity, which is determined by the flow rate through a fixed orifice. Stearates can be added to the powder to increase the flowability. .
• Compressibility: refers to the ratio of the volume of powder before compression to the volume of the article after compression.
• Apparent density: refers to the weight per unit volume.
• Sintering: refers to the operation of bonding metal particles to each other using a particular temperature. The better the sinterability, the greater the temperature range in which it can be used to sinter, i.e. easier.
• Porosity: refers to the ratio of space volume to total volume, which can be adjusted by particle size and distribution.

The essential advantage of the production process of powder metallurgy parts is that they have a high final forming ability and material utilization rate. Wisdom can make Stellite alloy parts with investment casting and powder metallurgy way. From our experiences, P/M can minimize the defects inside of parts brought by investment casting. Below is a comparative data of mechanical properties of Stellite 6 bars made by different process: