��1.Metallurgy Engineering Research Institute��University of Science and Technology Beijing�� Beijing 100083�� China 2.Fujian Sanming Steel Iron and Steel Group�� Sanming 365000�� China��
Abstract��The low-carbon cold heading steel ML08Al is the main steel grade used to produce standard parts and various non-standard parts with complicated shapes below grade 4.8. The finished products of self-tapping screw would have different defects due to the complexity of deep processing of steels. On the basis of the mechanical properties test of wire rod�� the metallographic and end morphology of defective self-tapping screws produced by ML08Al steel from hot-rolling state to finish state was analyzed by metallographic microscope and scanning electron microscopy (SEM). The reasons for defect formation in subsequent processing were determined. The results showed that the thread-rolling process had no significant influence on the microstructure morphology of materials. The formation of defects was greatly affected by the uneven distribution of carbides as well as inappropriate wire-drawing and thread-rolling processes.
�� �飬����淣��²�褣�������������. ML08Al�Թ��ݶ����������е�ȱ�ݷ���[J]. �й������ڿ���, 2015, 33(3): 40-44.
MENG Xiang��WANG Ming-di��CHEN Bo-yu��CHEN Yin-li��XU Li-ming. Defect analysis of self-tapping screw ML08Al in production. Chinese Journal of Iron and Steel, 2015, 33(3): 40-44.
2015, Vol. 33 
