Effect of different amounts of graphite on the sintering and transverse rupture properties of powder metal parts


Boz M. , Kurt A.

Journal of Materials Science and Technology, cilt.22, ss.419-422, 2006 (SCI Expanded İndekslerine Giren Dergi)

  • Cilt numarası: 22 Konu: 3
  • Basım Tarihi: 2006
  • Dergi Adı: Journal of Materials Science and Technology
  • Sayfa Sayısı: ss.419-422

Özet

Iron powders were mixed with graphite powders by 1 similar to 15 wt pct to produce block samples using powder metallurgy technique. The powders were blended in a three dimensional blender for 20 min and compacted in a die under 500 MPa by using a one directional press. Sinterability and mechanical properties of the samples with different carbon content were investigated. Sintering process was carried out on a belt furnace with flame curtain in dissociated ammonia atmosphere. Block samples produced were suitable for ASTM B-312 transverse rupture strength test apparatus and were tested with 0.050 kN/s velocity in a press under 100 g load. It was found that graphite amount up to 2 wt pct increased the contact area of particles and acted as a lubricant to affect the sintering behaviour positively. The results indicated that the samples containing up to 5 wt pct showed good sintering behaviour and also good hardness due to an increase in pearlite amount. However, the samples containing higher amount of graphite (more than 5 wt pct) affected the sintering behaviour negatively due to the settlement of free graphite around the Fe powders, which resulted in a decrease in the hardness and transverse rupture strength.