The Effect Of Ti Addition On Mechanical Performance And Densification Rate Of MIMHK30

Effect of Ti content on the mechanical properties and densification rate of metal injection molded HK30stainless steels have been investigated. Various contents of Ti (OWt.%,0.4Wt.%,0.8Wt.%and1.2Wt.%) were added into HK30stainless steels powder. The samples fabricated by the method of MIM (Metal Injection Molding) were sintered at1270℃,1290℃and1310℃respectively. The density, tensile strength, elongation and dimensional stability were tested. Densification behavior was research by analysis of densification rate and calculating activation energy of matter transfer for the samples with different content of Ti.Analysis of densification rate and activation energy of matter transfer calculated in relative density range of0.85-0.92showed the addition of Ti was beneficial to densification in the initial stage of densification, this is because that it eliminated impurities such as C and O around Ti particles. In the late stage of densification liquid-phase played a leading and decisive role on densification, Because Ti has priority over Fe in combining with C, it reduces and stabilize the content of C in HK30, and then it reduce the quantity of liquid and lower densification rate, and also lower the final density of the samples. On the other hand, it eliminated oversintering caused by rapid densification rate at high sintering temperature, Oversintering of samples sintered at1290℃and1310℃can be avoided by the addition of0.4%Ti, and it improved dimensional stability by making shrinkage behavior slower consistent.The recommended sintering scheme for HK30is1290℃/6h+0.4%Ti. In such scheme oversintering has been avoided and dimensional stability has been improved with tensile strength at800℃slightly decreasing, the samples have the best comprehensive properties.