จำนวน Repository ( 28 )
Abrasive wear behavior of diffusion layer by Pack Cementation on low carbon steel
This research aims to study abrasive wear behavior of diffusion layer by pack cementation on low carbon steel. Chemical compositions of pack cementation include 42wt% Ferro-silicon 17wt% sand 3wt% NH4Cl 12wt% clay and 26wt% Liquid glass. The specimens were heated in the induction furnace at 950?C and 1050?C for 20 and 30 hrs. Microstructure of diffusion layer was analyzed with Optical and Scanning Electron Microscopy and hardness of diffusion layer was tested with a Vickers indenter. The abrasive wear tests were carried out in a Dry Sand Rubber Wheel abrasion machine according to ASTM G65 standard. Results showed that the heating temperature of 1050?C for 20 hrs. yielded high hardness level of approximately 394.26HV0.02 and low average wear resistance of 0.0751g. The worn surface exhibited deep grooves. On the other hand the heated treatment for 30 hrs. yielded the highest diffusion layer of approximately 910?m and the microstructure of Fe5Si3 ?1 and ?Fe.
การประยุกต์ใช้ฟิล์มแข็งเคลือบผิวเพื่อยืดอายุพันช์เอียงในกระบวนการตัดขอบ
The objective of this research is to increase the tool life of trimming process by surface coating technology. The procedure of this research consists of two sections. In the first section the friction coefficient was investigated with the ball on disk technique by using a tribometer. Steel ball was produced from cold work tool steel grade SKD11 (JIS) hardened to 60±2 HRC. Two types of surface coating namely AlCrN and TiAlN were conducted by PVD technique. Disk material used in this experiment was made by stainless steel JIS; SUS 304 of 2 mm thickness. For the second section the wear tests of trimming die were performed by using flat punch and inclined punch 45 degrees without surface coating as well as the inclined punch 45 degrees coated with AlCrN and TiAlN (PVD). Workpiece material used for the wear test was stainless steel JIS; SUS 304 of 2 mm thickness. Additionally the finite element analysis was carried out for explanation the deformation of the workpiece during trimming operation. Although the friction coefficient of the surface coating was higher than non-coating it could be extended the tool life ostensibly. As the result of FEM the inclined punch 45 degrees could be generated the long sheared surface more than the flat punch. This is due to the internal stress of workpiece that did not connect from the punch to the die so the crack propagation would be delayed. The inclined punch 45 degrees coated TiAlN has a highly durable which can be used up to 5000 strokes.
การปรับปรุงสมบัติทางไทรโบโลยีของผิวอะลูมิเนียมด้วยกระบวนการอโนไดซ์เสริมนาโนไททาเนียมไดออกไซด์
Aluminium was used in many industrial applications due to good properties such as ductile high corrosion resistant and high electrical conductivity. Since wear resistance of aluminium was very poor so that it was a limitation of using this material in several conditions. In this research aluminium was improved the wear resistance properties by using anodizing process and adding some titanium dioxide particles on the surface. The effect of anodizing process duration on the wear resistence property was studied. It was found that the process duration and amount of titanium dioxide play the important role on improvement of tribological properties of aluminium.