304不銹鋼線經兩道冷抽與熱處理加工之拉伸性質與破壞斷面形貌的探討

Tensile Property and Fracture Morphology of 304 Stainless Steel Wires after Two-pass Cold Drawing and Heat Treatment Processes

石天威(T. W. Shyr) ； 黃詩茹(S. J. Huang) ； 牟明達(M. T. Mou)

《紡織綜合研究期刊》 26卷3期 (2016/07) Pp. 7-18

https://doi.org/10.6439/TTRJ.201607_26(3).0002

摘要

304不銹鋼線經兩道冷抽及熱處理後，以拉伸試驗機量測不銹鋼線之機械性質，並以掃描式電子顯微鏡觀察破壞斷面形態及韌窩形態與分佈等微觀結構變化，探討304不銹鋼線經冷抽及熱處理後之機械性質和破壞斷面的關係。實驗結果顯示，所有不銹鋼線之破壞斷面均產生明顯的頸縮現象，皆屬韌性斷裂，且拉伸應變越大者，頸縮率越大。由破壞斷面宏觀形貌可知，經冷抽後，線材的韌窩尺寸變異也較大，分佈較不密集，空孔較多，且有些空孔擴展成較大的空穴。然而，熱處理後，延伸性較好之線材，韌窩尺寸較小，尺寸變異也較小，且韌窩緊密相鄰。此外，於此系列不銹鋼線之破壞斷面皆發現介在物，推測304不銹鋼線之機械性質除了受多晶相組織及空孔成核位置控制，也可能受到介在物影響。

關鍵字

304不銹鋼線材 ； 冷抽 ； 熱處理 ； 斷面形態 ； 韌窩

並列摘要

The relationship between tensile property and fracture morphology of the 304 stainless steel wires after two-pass cold drawing and heat treatment process was investigated. The tensile property was measured using a mechanical testing machine. The fracture morphology and the morphology and distribution of the dimples were observed using a scanning electron microscope. The results showed that all of the 304 stainless steel wires were ductile fracture with varied necking appearances obviously. The necking ratios were increased with an increase of the tensile strains. After the cold drawing process, the distribution dimples was turned into loose and the size variations of dimples were great from center to edge of the cross section. There were many voids on the fracture surfaces of the cold drawn wires, and some of the voids extended to large cavities. In contrast, the heat treated 304 stainless steel wires had a good ductility. Their dimple sizes and size variations were small and the dimples were close to each other. Furthermore, the inclusions were found in all the fracture surfaces. The tensile property was not only controlled by multi-crystalline phases and void nucleation sites, but may also be affected by inclusions.

並列關鍵字

304 stainless steel wire ； cold drawing ； heat treatment ； fracture morphology ； dimple