论文部分内容阅读
以经不同工艺退火的Qst32-3超低碳钢为研究对象,利用金相显微镜、硬度计等研究扭转变形过程中显微组织和性能的演化,利用扫描电镜对扭转断口进行形貌观察。结果表明,扭转变形可促进不充分静态再结晶进行。这主要与温度升高促进溶质原子扩散,降低再结晶激活能以及促进位错运动,缩短再结晶形核时间等因素有关。与退火不充分的试样相比,再结晶充分的样品经扭转变形后,其断口宏观呈平齐状。微观断口形貌显示,前者扭转后心部孔洞较大,撕裂棱明显,后者断口心部孔洞小而浅,韧窝呈剪切状,且无明显的撕裂棱存在。表明,充分退火后材料具有更优的扭转性能。
The Qst32-3 ultra-low carbon steel, which has been annealed by different processes, was studied by means of metallographic microscope and hardness tester to study the evolution of microstructure and properties during the torsional deformation. The morphology of the twisted fracture was observed by scanning electron microscopy. The results show that torsional deformation can promote incomplete static recrystallization. This is mainly related to the factors such as the increase of temperature, the diffusion of solute atoms, the decrease of recrystallization activation energy, the promotion of dislocation movement and the shortening of recrystallization nucleation time. Compared with the samples with insufficient annealing, the macroscopically fractured macroscopically fractured after the samples with sufficient recrystallization were deformed by twisting. The microscopic fracture morphology shows that the former has a large heart hole and a sharp tear edge after twisting, while the latter has small and shallow holes in the heart of the fracture, and the dimples are in a shear shape with no obvious tear edges. It shows that the material has better torsion performance after fully annealed.