The study of flow stress and damage on cold forging steels

• Main Authors: CHEN,WEI, 陳暐
• Other Authors: HSU,CHAO-HO
• Format: Others
• Language: zh-TW
• Published: 2016
• Online Access: http://ndltd.ncl.edu.tw/handle/3h8db2

碩士 === 國立高雄應用科技大學 === 模具工程系 === 104 === The purpose of this study was to transform the flow stress by detecting the compression of three types of cold-forming without heating thermal refining steels, NO.3311, NO.3319 and NO. 3492, and SCM440 with twice-spheroidizing annealed. Through this testing, we could find out the flow stress and the critical region of the ductile fracture of a material model.We expected to establish a material storage for CAE software (DEFORM), and offer it to analyze CAE. The study was conducted by reducing the expansion of the cylinder compression and raising the accuracy in the displacement curve. We demanded to reduce the expansion of the cylinder compression by decreasing the shear friction coefficient between the compression model and the test fragment. We received the flow stress curve through correcting the expansion of the cylinder compression. We inputted the curve in DEFORM software, established the model to conduct a simulation analysis, and compared the result with the simulation analysis. We examined the cylinder compression to find out the process of the damaged surface. We also used the simulation analysis of DEFORM to calculate the critical region of the ductile fracture. Finally, we combined the critical region of the ductile fracture with DEFORM in the material storage. Comparing with eleven different procedures of compression, the result of the cylinder compression was received that the minimum magnitude of the error term was less than 1% while the maximum magnitude of the error term was less than 2% in four different cold-forming steels.