射出成形17-4PH不銹鋼之顯微組織及機械性質研究

金屬粉末射出成形之17-4PH不銹鋼具有良好的機械性質與抗腐蝕性，已廣泛應用在汽機車、航太和電子零組件等不同領域上。有別於傳統粉末冶金技術，使用粉末射出成形可以有效的提升金屬製品的燒結密度，同時適合自動化以及大量生產。本研究使用的17-4PH為析出硬化型不銹鋼，使用水噴霧粉以及氣噴霧粉兩種不同粉末燒結而成，並使用真空和裂解氨做為燒結氣氛，以不同的熱處理方式，包含燒結後、固溶處理、時效處理(H900和H1100)，比較在使用不同粉末、燒結氣氛、熱處理方式對顯微組織及機械性質的影響。實驗結果發現，在兩種燒結氣氛下氣噴霧粉試片的燒結密度都比水噴霧粉試片還高。氣噴霧粉真空燒結之17-4PH不銹鋼在經過 H900後，抗拉強度為1297 MPa，伸長率為10.9 %，硬度為HRC 39，δ肥粒鐵含量為12.8 %，擁有本實驗中最高的抗拉強度以及δ肥粒鐵含量。而使用氣噴霧粉在裂解氨燒結且經H1100的試片抗拉強度為1092 MPa，伸長率為15 %，HRC 33，其高延性乃因顯微組織具有沃斯田鐵所致。水噴霧粉在燒結後，顯微組織中含有許多的二氧化矽，會使燒結密度與機械性質產生劣化的現象。使用裂解氨燒結後會導致δ肥粒鐵相大幅減少，同時使不銹鋼性質轉變成硬脆的情形。

關鍵字

金屬射出成形； 17-4 PH ；固溶處理；時效處理；燒結；顯微組織

並列摘要

Metal injection moldind (MIM) 17-4PH stainless steel have been widely used in the various fields due to the excellent mechanical properties and corrosion behaviors. In general, the sintered density of MIM part is higher than that of PM one. The objective of this study was to clarify the influences of powder types (water-atomized and gas-atomized powders), sintering atmospheres (vacuum and cracked ammonia), and heat treatments (sintering, solutioning, H900, and H1100) on the microstructure and mechanical properties. The findings indicated that the sintered densities of steels made by gas-atomized powders are higher than those made by water-atomized powders, irrespective of sintering atmospheres and heat treatments. The 17-4PH steels produced by gas-atomized powders in combinations of vacuum sintering and H900 treatments have best properties investigated in this study. The ultimate tensile strength, elongation, and hardness can achieve to 1297 MPa, 10.9 %, and HRC 39, respectively. Moreover, the ultimate tensile strength, elongation, and hardness of the steels produced by gas-atomized powders in combinations of ammonia sintering and H1100 treatments is 1092 MPa, 15 %, and HRC 33, respectively. This high elongation can be attributed to the presence of reversed austenite.

並列關鍵字

Metal powder injection molding ； 17-4 PH stainless steel ； solution treatment ； aging treatment ； sintering ； microstructure

參考文獻

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[7] J. H. Wu and C. K. Lin, “Tensile and Fatigue Properties of 17-4 PH Stainless Steel at High Temperatures”, Metallurgical and Materials Transaction A, Vol. 33, 2002, pp. 1715-1723.

[9] 陳柏翰，“金屬射出成形17-4 PH不鏽鋼之機械性質及加工性之改進”，碩士論文，國立臺灣大學材料科學與工程學研究所，2010，1-45頁。

[11] MPIF Standard 35, Materials Standards For Metal Injection Molded Parts, 2007, pp. 19.

[12] P. Imgrund, A. Rota, and A. Simchi , “Microinjection moulding of 316L/17-4PH and 316L/Fe powders for fabrication of magnetic–nonmagnetic bimetals”, Journal of Materials Processing Technology, Vol. 200, Iss. 1-3, 2008, pp. 259–264.

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射出成形17-4PH不銹鋼之顯微組織及機械性質研究

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