氮化處理對SACM 645機械性質之影響

Effects of Nitriding Processes on the Mechanical Properties of SACM 645 Steel

葉書宏(Shu-Hung Yeh)

指導教授 ： 邱六合

大同大學/工程學院/材料工程學系所/碩士(2008年)

摘要

本研究目的在於探討JIS SACM 645滲氮用合金鋼進行氣體及電漿滲氮處理後對機械性質的影響。於氣體滲氮製程中，比較滲氮時間及基材硬度對機械性質的影響；電漿滲氮是在530℃持溫24小時的條件下進行，並與同參數之氣體滲氮製程做比較。以磨耗試驗、耐疲勞試驗及耐腐蝕性等分析，確認經滲氮處理條件提升表面硬度，增加耐磨耗和耐疲勞性，並提升耐腐蝕性質。由XRD分析結果得知，SACM 645氮化鋼經氣體及電漿滲氮後，其表面形成一層由Fe3N所組成之化合物層，俗稱白層，其硬度介於1000~1100HV0.1之間。由磨耗結果顯示，在530℃下施以氣體滲氮，耐磨耗性隨滲氮時間及基材硬度的增加而增加。電漿滲氮件的耐磨性優於氣體滲氮件。氮化在SACM 645鋼材表面形成Fe2-3N和Fe4N化合物層，降低腐蝕電流密度，使耐腐蝕性得以改善。而SACM 645滲氮之前先經淬火回火後在高溫回火到35HRC再經530℃氣體滲氮48小時的情況下，其疲勞限由416MPa提高到632MPa，增加51.9％，為本研究之最佳提高耐疲勞特性之製程參數。

關鍵字

氮化 ； 疲勞 ； 磨耗

並列摘要

This research is to study the effect of the nitrided case produced by gas and plasma nitriding processes on the fatigue and wear endurance of the JIS SACM 645 steel. In gas nitriding, the effect of different substrate hardness and nitriding holding time was compared, Plasma nitriding was carried out at 530°C for 24h, and compared with gas nitriding. The hardness of surface layers of the nitrided specimens was fallen in the range between 1000–1100HV0.1, and the phases of the nitrided case were consisted of Fe2-3N and Fe4N. Wear test result indicated that the mass loss of JIS SACM 645 steel was greatly reduced by nitriding processes. From the mass loss data, the wear resistance of the steel was significantly influenced by nitriding time. The fatigue strength of the 35C-GN48 nitrided specimen was risen to 632 MPa, which was the maximum fatigue strength in this study.

並列關鍵字

Nitriding ； Fatigue ； Wear

參考文獻

[13] 鄭至偉, 冷作工具鋼經固體粉末滲氮後之耐磨性研究, 碩士論文（2006）.

[5] J. Baranowska, M. Wysiecki, “Influence of surface pretreatment on case formation during gaseous nitriding,” Surface and Coating Technology, Vol. 125, pp.30-34, 2000.

[6] S. Abisset, F. Maury, R. Feurer, M. Ducarroir, M. Nadal, M. Andrieux, “Gas and plasma nitriding pretreatments of steel substrates before CVD growth of hard refractory coatings,” Thin Solid Films, Vol. 315, pp.179-185, 1998.

[7] C. Allen, C.X. Li, T. Bell, Y. Sun, “The effect of fretting on the fatigue behavior of plasma nitrided stainless steel,” Wear, Vol. 254, pp.1106-1112, 2003.

[8] F. Ashrafizadeh, “Influence of plasma and gas nitriding on fatigue resistance of plain carbon（Ck45）steel,” Surface and Coating Technology, Vol. 173-174, pp.1196-1200, 2003.