The Color Uniform Study Of Mending Agent Repair Casting Defect

A large number of facts show that the method of repair putty,is widely used forcast iron,cast steel,non-ferrous metal casting to repair the defects (such as shrinkage、pore、sand hole、pit and so on) on the assembly surface and working surface.Compared with the traditional welding repair, its process is very simple, low cost, highefficiency and quality assurance. The strength is the most important internal qualityindicator, and the color of repairing weather consistent with the casting or not,is animportant symbol of appearance quality for repairing.Based on the surface coating technique and the theory of colorimetry, usingmending agent to repair the casting defects、, applying the Value and the chromaticitycoordinate in the CIE LAB colorimetric system to describe the color of objects. Usespectrophotometer on casting and the repaired defect to measure their color, study onthe effects of metal composition, organization and the surface condition on its colormeasurement, and the color uniform after repairing the casting defects by mendingagent. Also study on the effects of pigment on the mending agent for its color and itsadhesive property.The main conclusions of this study are：①The surface condition of the metal is different, reflecting the color of the metaldifferent.The surface is brighter and the color of the materials is brighter, and the indexof its value L*is higher, the color and lustre is lighter. Also, the composition,organization and the surface condition of the metal is different, the color of the metal isdifferent.②In the experiment, there is a big difference between the color of putty and thecolor of metal. As the mass fraction of the white pigment titanium or the metal pigmentaluminum powder in the mending agent is range from1%to4%, the value L*of themending agent color is increasing, but it is still different from the color of themetal.The reason is that the surface of the metal is very smooth,it can reflect more than50%the incident light and show the characteristic of the metal in metallic luster.For thesame mass fraction, it is easier for the white pigment titanium to change color lightnessparameter values of L*than the metal pigment aluminum powder.③Experiment designed tensile test under the normal to research the adhesivestrength of the mending agent. As the mass fraction of the white pigment titanium or the metal pigment aluminum powder in the mending agent is range from1%to4%, theadhesive strength is different. The Anatase titanium make the adhesive strengthdecrease; Rutile titanium pigment is mending adhesive strength; but the aluminumpowder make the adhesive strength increased before it is reduced.