Sintering

The operation of heating the green compact at high temperature in a controlled atmosphere (Reducing atmosphere which protects oxidation of metal powders). The Sintering increases the bond between the particles and therefore strengthens a powder metal compact. Sintering temperature and time of sintering depends on the type of powders and the strength required in a final product. The Sintering temperatures usually 0.6 to 0.8 times the melting point of powders.

Type of powder                                   Sintering Temperature                 Time
Aluminium & Alloys                                   370 – 520 C                                  24 hrs
Copper, Brass, Bronze                                700 – 900 C                                  30 Mins
Iron                                                           1025 – 1200 C                              30 Mins
Stainless Steel                                           1180 C                                       20 – 40 Mins
Tungsten Carbide                                      1480 C                                      20 – 40 Mins   

Spark Sintering:
 

The process of simultaneous pressing & Sintering of metal powders by high energy electric spark. This spark is discharged from capacitor bank & removes the surface contaminants from powder particles. This cause the particles to form a solid cohesive mass. Immediately after spark, the current is continued for about 10 Seconds, with high temperature which further strengthens the bond used for sintering Aluminium, Copper, Iron and Stainless Steel.