Study on mechanical properties of warm compacted iron-base materials

Abstract

Mechanical properties of the warm compacted iron-base powder metallurgy materials were compared with those of conventional cold compacted materials. Factors such as compaction temperature, lubricant concentration and lubricant’s property were studied. A lubricant for warm compaction powder metallurgy was developed. An iron-based powder metallurgy material with a green density of 7.31 g/cm³ (a relative density of 92.5%) can be obtained by pressing the powder at 700 MPa and 175 °C. The sintered materials have a density of 7.2 g/cm³, an elongation of 2.1% and a tensile strength of 751 MPa compared to 546 MPa using conventional cold compaction with the same lubricant and 655 MPa using warm compaction with other lubricant. Compact density and mechanical properties were influenced strongly by the compacting temperature. Although the best quality compacts can be obtained at 175 °C, warm compaction within 165 to 185 °C can give high density compacts. Evidence shows that compact density depends on the friction coefficient of the lubricant.

Keywords

warm compaction / powder metallurgy / mechanical property

References

[1] Hoeganaes Corporation web page[DB/OL]. http://www.hoeganaes.com/home.htm, May 2000.

[2] Shah M N and Isaacs J A. P/M processing of gear components: case studies of economic competitiveness[A]. Ferguson H and Whychell D T ed. Advances in Powder Metallurgy and Particulate Materials-2000, Part 10, Metal Powder Industry Federation[C]. Princeton, NJ. 2000. 10–19.

[3] EngstroemU, JohanssonB, RutzH, et al.. High density PM materials for future applications PA 94[J]. European Powder Metallurgy Association, 1994, 1: 57-57

[4] RutzH, HanejkoF, LukS. Warm compaction offers high density at low cost[J]. Met Powder Report, 1994, 9: 40-47

[5] JamesW B. Recent developments in ferrous powder metallurgy alloys[J]. Int J Powder Metall, 1994, 30(2): 157-162

[6] RutzH G, HanejkoF G. High density processing of high performance ferrous materials [J]. Int J Powder Metall, 1995, 31(1): 9-17

[7] CaoS, GaoH, QuX. Study on the possibility of water-atomized alloy powder utilized base materials for warm compaction[J]. Powder Metall Mater Sci and Eng, 2001, 6(2): 128-133(in Chinese)

[8] CaoS, YiJ, QuX, et al.. Design of high density powder mixtures for warm compaction[J]. J Central South University of Technology, 2000, 31(6): 532-535(in Chinese)

[9] LiM, GuoS, LinT. The effect of compacting parameters on densification of warm compacted iron powders[J]. Powder Metall Industry, 2001, 11(3): 29-33(in Chinese)

[10] XiangP F, LiY Y, LongY, et al.. Effects of Polymeric Lubricant Adding Method on the Warm Compaction Powder Metallurgy[J]. Mater for Mech Eng, 2001, 25(3): 23-24(in Chinese)

[11] LiY Y, XiangP F, XuZ, et al.. The Densification Mechanism of Warm Compaction Technology[J]. Mater for Mech Eng, 2001, 19(1): 39-42(in Chinese)

[12] LiYuangyuan, XiaoZhiyu, NgaiT L, et al.. Warm compaction NbC particulate reinforced iron-base composite(I): Effect of fabrication parameters [J]. Trans Nonferrous Met Soc China, 2002, 12(4): 659-663

[13] LiYuanyuan, XiaoZhiyu, NgaiT L, et al.. Warm compaction NbC particulate reinforced iron-base composite (II): Microstructure and properties[J]. Trans Nonferrous Met Soc China, 2002, 12(4): 664-668