Papers by Author: Ke Qiang Yu

Abstract: Flow phenomenon in spot welding nugget of dissimilar materials was studied. Metallographs in the course of welding nugget formation were observed and analyzed, through which it was indicated that: in the early stage of welding nugget formation, spot welding of dissimilar materials made liquid metals in the nugget produce a violent stirring action because the electrodynamic force overcame the medium resistance, causing unevenness of elements and compositions in the welding nugget; and then the unevenness was represented by vortex flow by means of different resistances to corrosion. It was proposed that the formation law of welding nugget could be recognized according to the formation law of vortex flow, and the vortex flow often moved from later-molten metal to former-molten metal. The property of welded joint with vortex flow was poorer than that without vortex flow.

Abstract: 4J29 is a typical of expansion alloy and used as sealing glass material and structure material in transistors, integrated circuit devices manufacturing industry. This article adopts heat-treatment experiments and single factor optimization method to study the relationships of recrystallization temperature, beforehand deformation and grain sizes on 4J29 alloy; then discusses the reason why the coarse grain phenomena appear and gives technological measures to improve the quality and performance of workpiece

Abstract: In producing stainless steel cold rolling strip, stripe and decorative pattern shape defects occur on the surface, and influence its quality. This paper uses the spot investigation, defects microscopic analysis and scanning electron microscopy spectrometer methods in order to give a detailed analysis about surface defects, discusses the essence of defects, causes and effects process, puts forward valuable suggestions and provides reliable data for the actual production.

Abstract: As the only known grinding media of magnetic barrel finishing, stainless steel pins are widely utilized to polish surfaces of some small workpieces. Through comparative research of several grinding media including pins as well as their compound, this paper introduces a new improved method by mixing pins with magnetic abrasive particles based on the electro-magnetic barrel finishing process. The experimental results prove its effectiveness.

Abstract: Traditional magnetic grinding method has great advantage in polishing small workpieces with complicated surfaces. However, this method has obvious limitation in actual applications. A new method called electro-magnetic grinding which solves defects of traditional magnetic grinding is presented and processing mechanism for small workpieces with complicated surfaces is introduced in this paper.