Microstructure And Mechanical Properties Of Card Clothing And Its Chemical Nickeling Process

The chemical component, microstructure and mechanic properties are analyzed of the local card clothing of SWRH72B, SWRH57B made by a famous manufacturer and OK40, OB20 made by Graf company in Switzerland. Several views are raised on the possibility to improve the abrasion resistance and inside quantity of card clothing on materials and manufacturing process. The results show that: (1) In the aspect of alloying components: The C content of abroad products is higher, already to 0.8%. P, S contents are very low for 0.008%, and alloying elements W, V, Cr are added, which content is 0.7%~1.6%. (2) In the aspect of the microstructure: The abroad tips microstructure is much thin aphanic martensite + retained austenite+ dispersion particle carbide, the carbide distributes even and is the first degree, but the domestic is more rough aphanic martensite + retained austenite + little dispersion carbide, and the decarbonization in the edge is also serious. The abroad has an ideal microstructure of spherical pearlite on the base, but the domestic is more bulky. The particle carbide is obviously bigger and the amount is more than the domestic. The quenching depth of the abroad tips is obviously higher than the domestic. The quenching depth percent is different, and OK 40 is 84%, but the local is only 34%. (3) In the aspect of the microhardness: The abroad tips hardness is higher than the local and to be over HV900 and some is higher than HV1000.The hardness of 2 of the abroad is above HV900, but the local is only HV400 and not stable. The hardness on the base of the abroad is higher than the local, which is between HV145 and HV200 and not even, but the abroad is between HV230 and HV270. (4) A plating coat is found on the abroad tips. So the advices on new material, better heat treatment and surface treatment and its equipment are given.The chemical nickeling process for the card clothing under acid condition is analyzed .The most suitable component of plating solution and the best plating technology is obtained by studying the influencing factors of temperature, pH, etc. Then a reasonable chemical nickeling process on card clothing is designed. Finally thedomestic product of cylinder card clothing wires of AC4045 is plated. The research on the principle and the relation between the time and thickness, structure, property of plating coat is given. Results indicated that: (1) Under this given conditions, the relation between the increment of weight and the time is Y=0.0005X+0.0013, related coefficient r =0.989128557. The speed of plating is stable in a short time. (2) A plating coat of low phosphorus is got. The plating coat has both the main sedimentation enhances (Ni3C phase), and solution strengthening (the P dissolves into the Ni sosoloid solid solution) enhancation mechanisms. After heat treatment, the hardness reaches to HV1000. (3) As is shown in the paper, when the chemical plating time on the card clothing is within the scope of 8~10 min, the thickness of plating coat is already above 6um. The abrasion experiment shows that the surface abrasion resistance of the card clothing is highly increased, which is 2 to 3 times than the common quenching wires. In a word, the surface treatment of chemical nickel-plating on the card clothing wires is viable.In the end, a production line of chemical nickeling plating on the burnishing card clothing is designed by using the results of experiments.