不同預處理對球墨鑄鐵軟氮化處理的影響

本研究探討球墨鑄鐵FCD550進行氮化反應前經過不同的預處理，包含珠擊與磷酸鹽處理，對氮化製程效果的影響。首先選擇適當的氮化溫度，選定後將鑄鐵在氮化前以不同尺寸的鋼珠對表面進行珠擊，再進行氮化製程；磷酸鹽預處理的部分則是以磷酸鋅預處理15分鐘、磷酸錳預處理15分鐘和磷酸錳預處理30分鐘，共3種磷酸鹽處理條件，再進行氮化製程。檢測方法則分別是使用微克氏硬度機(Vickers hardness tester)檢測表面硬度和截面硬度分布曲線、X-ray繞射測量儀(XRD)檢測其結晶相種類、金相顯微鏡(OM)進行微觀組織的分析和孔隙率的探討、表面粗度計(Surfcom)檢測珠擊過後的表面粗糙度、應力量測儀(Stress Mea- surement System)檢測珠擊過後產生的壓應力。針對球墨鑄鐵FCD550，藉由選用三種不同的溫度參數進行氮化製程測試，結果發現在530℃的氮化條件下，可得到最大表面硬度與最低孔隙率。預處理的部分，發現藉由不同珠擊參數進行表面清潔後，使用530℃進行氮化試樣會因為壓應力不同造成不同程度的面粗度，其中0.8mm的鋼珠進行珠擊後的面粗度能些微提升氮化效益。而使用磷酸鹽預處理後再使用530℃進行氮化試樣，會因為不同種類的磷酸鹽處理，而在氮化製程下，產生不同程度的化學反應，而明顯地提升氮化效益，且多孔層較薄。

關鍵字

球墨鑄鐵；氣體軟氮化；多孔層；珠擊；磷酸鹽處理

並列摘要

The purpose for the study was to assess the effects of different Nitriding Pretreatments on the nodular cast iron FCD550, including use the shot peening treatment or phosphate treatment. First of all, testing personnel choose the suitable nitrocarburing temperatures and using different sizes of the steel ball to shot peening (0.15mm, 0.25mm, and 0.8mm steel balls ) the surface of nodular cast iron FCD550 before the cast iron put into Nitriding Pretreatments. Then separately using zinc phosphate for 15 minutes, manganese phosphate for 15 minutes, manganese phosphate for 30 minutes of nodular cast iron FCD550 before the cast iron put into Nitriding Pretreatments. For shot peening to create six different surface pretreatment conditions, and choose the 530℃ nitrocarburing. Then Vickers Type Tester, X-ray diffraction measuring instrument (XRD), Microscope, surface roughness, shape measuring instrument (Surfcom) and the Stress Measurement System were used for characterization to help figure out the mechanisms For the graphite cast iron (FCD550), the nitriding process was tested by selecting three different temperature parameters. It was found that the maximum surface hardness and the lowest porosity were obtained under nitriding temperature of 530 °C. In the pretreatment, it was found that sample has different effects on the porous layer after shot peening, and the 0.8 mm steel ball can slightly improve the nitriding efficiency. And in it was found that different phosphate treatment before nitriding have different resulted. The results showed that the phosphate treated sample improves nitriding efficiency and makes the porous layer thinner

並列關鍵字

Graphite cast iron ； Nitrocarburing ； Porous layer ； Shot peening ； Phosphate treatment

參考文獻

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[1] W. L. Chen, C. L. Wu, Z. R. Liu, S. Ni, Y. Hong, Y. Zhang, and J. H. Chen, "Phase transformations in the nitrocarburizing surface of carbon steels revisited by microstructure and property characterizations", ScienceDirect, Vol. 61, pp. 3963-3972, 2013.