J Mater Sci Technol ›› 2006, Vol. 22 ›› Issue (03): 419-422.

• Research Articles • Previous Articles     Next Articles

Effect of Different Amounts of Graphite on the Sintering and Transverse Rupture Properties of Powder Metal Parts

Mustafa Boz, Adem Kurt   

  1. Karabuk Technical Education Faculty, Zonguldak Karaelmas University, Karabuk, 78050, Turkey...
  • Received:2004-11-12 Revised:2005-03-18 Online:2006-05-28 Published:2009-10-10
  • Contact: Mustafa Boz

Abstract: Iron powders were mixed with graphite powders by 1~15 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.

Key words: Powder metallurgy, Sintering, Fe, Graphite, Transverse rupture strength