Study On The Mechanism And Preparation Of Anti-adhesion Inner Surface On Small Diameter Stainless Steel Pipe

Small-diameter stainless steel pipe, which has good resistance to corrosion, has been widely used in the fields of medicine, food, semiconductor and nuclear industry, where corrosive fluids need to be transported. Anti-adhesion property on the surface of stainless steel pipe is one of factors which strongly affect the transport efficiency, corrosion resistance and the accuracy of flow transmission. However, the study about mechanism of liquid adhesion on the solid surface is relatively shortly, which is unable to provide effective theoretical support for the preparation of the anti-adhesive pipe surface. Simultaneously, it is difficult to meet the increasing market demand of high quality for the current inner-surface polishing techniques, due to the small diameter and large ratio of stainless steel pipe on the fields. Therefore, there is an important theoretical and practical significance to research the mechanism of liquid adhesion and the preparation technology of anti-adhesion surface for small-diameter stainless pipe.To clarify the mechanism of liquid adhesive on solid surfaces, the thermodynamic state equation in a three-phase system has been presented based on a simplified 2-D model of triangular contour on solid surfaces, through the analysis and characterization of geometric morphology on the machined surfaces. A model of the relationship between solid surface droplet instantaneous contact angle and systematic free energy has also been built, which demonstrates the main factors of the dynamic movement of the three-phase contact line. In addition, in order to demonstrate the correctness of the established model, experiments investigating anisotropic wetting characterized by the static contact angle and droplet’s distortion, have been implemented on machined surfaces with different roughness on hydrophilic organic materials and hydrophobic metallic materials. Finally, it has been found that the energy barrier caused by roughness and the wetting states affected by surface chemical composition are the main factors affecting the anti-adhesion capacity of solid surfaces, which identifies the research direction for the preparation of anti-adhesion inner surface on small-diameter stainless pipe.From the perspective of reducing the surfaces’energy barrier, electrochemical polishing was adopted to deal with the inner surface on small-diameter pipe based on the comprehensive analysis of the pipe’s structural characteristics and the advantages and disadvantages of different polishing processes. Based on the analysis of the material removal mechanism of electrochemical polishing, a detailed structural design and optimization from overall mechanical structure, the electrolyte heating, electrolyte circulation, detection systems and devices NC system was also considered. Finally, the electrochemical polishing apparatus was set up for inner surface of stainless steel pipe.The experimental study on electrochemical process parameters affecting on the polishing quality of the pipe inner surface was implemented by the apparatus. Experimental results show that the tool electrode with spiral grooves effectively improves the update rate of the electrolyte within the pipe and the polishing quality on inner surfaces, compared with the conventional cylindrical tool electrode. The current density, the revolving speed of the tool electrode, the feed rate of the tool electrode, the temperature of electrolyte, the flow rate of electrolyte, machining gap and machining time also have stronge effects on the polishing quality on inner surfaces. Eventually, through an optimization of electrochemical process parameter, an inner surface with Rc 0.14μm of the pipe was obtained.These efforts have shown theoretical and practical significance on the development of anti-adhesion theory and the preparation on small-diameter stainless steel pipe in the micro-fluid transportation field.