Experimental Study On Large Ingot Mold Coating

China's aviation and aerospace, shipbuilding, electric power, petrochemical strong demand for large casting and forging, strengthening of the Forging research and development related technologies to explore the technology is reliable, economical process method, Juyou important to the scientific value and practical significance. Forging their quality, and is closely related to the quality of steel ingots. Paint in liquid steel ingot mold casting process, molten steel and the die wall as the middle layer, heat transfer plays a regulatory role, not only can reduce the liquid steel ingot mold die wall on the thermal shock, in order to improve quality and increase ingot solidification Ingot mold service life, but also help ingot mold release, reduce scarring and other defects, increase the rate of finished steel ingot.In this paper, a large steel ingot mold coating for the study, under the conditions of the different composition of the basic formula of the coating experiments, the melting point by examining the paint, suspension, coating thickness, coating temperature strength and high temperature strength properties, and the help of differential thermal analysis and phase of analysis, good performance of paint formulations, coatings based on this orthogonal optimization to obtain the best ratio of paint, and make cost estimates. Laboratory experiments by pouring paint application effect observed, and a large steel ingot to simulate the thermal environment, clear coatings in this environment changes. The main research contents and the results are as follows:(1) By a combination of aggregate and form the adhesive coating into water glass coating combined with the quality of quartz, sodium silicate combination of aluminosilicate coating, silica coating combined with aluminosilicate, colloidal silica combined with magnesia coating, sodium silicate and magnesium sulfate quality coating, phosphate coating combined with aluminosilicate coatings composed of six formula, melting point by examining the six paint, suspension, coating thickness, baking temperature after coating the surface quality and surface quality after high temperature baking, and with Thermal analysis and phase analysis of experiments, and good performance of coatings formulations. The results show that: the quality of phosphate coating combined with Mg to 1450℃above the melting point of the slurry ratio of 2:1 (non-aqueous coating composition and applied to water ratio), the viscosity of about 20 parked paint, coating suspension to 97% the coating thickness is about 0.4mm, coated and low and high temperature baking the surface smooth, no dropped powder, anti-cracking resistance is one; double inorganic adhesive bonded magnesia coating above 1450℃, the slurry ratio of 2 : 1 (non-aqueous coating composition and applied to water ratio), the coating viscosity of about 20 parked, coating suspension to 85%, coating thickness is about 0.4mm, low and high temperature baking after coating the surface smooth, No swap powder, resistance to cracking of the one.(2) The combination of Mg, Al-quality phosphate coating and double coating inorganic adhesive bonded magnesia as the experimental object, the coating composition according to five factors, four levels Optimize the formula, get the best composition of paint, and paint cost estimates. The results show that: the quality of phosphate coating in the bauxite alumina combined 10-15%, 60-75% magnesite powder, the remaining materials account for 10-30% of the composition, the coating has good resistance to cracking, low strength and high temperature strength properties; pair of inorganic coating adhesive bonded magnesia magnesite powder in 60-75%, 0.7-1% sodium hexametaphosphate, and the remaining material composed of about 25-40%, the coating has a good Crack Resistance, low strength and high temperature strength properties; through the paint for the cost estimates, phosphate and magnesium silicon coating about 850 yuan / ton, double-inorganic bonded magnesia coating is about 730 yuan / ton.(3) the optimized combination of magnesium phosphate inorganic silica coating and double coating adhesive bonded magnesia casting laboratory experiments carried out in slurry ratio of 2:1 were investigated under conditions of different coating thickness effect under the application of paint, also looked at the cold steel ingot, hot stripping effect when applied. And a large steel ingot casting simulation of the thermal environment to study the changes in coating high temperature strength. The results show that: the coating thickness of 0.3mm, the coating surface quality is better, after drying and curing, cracking resistance to a coating thickness of 1mm, the coating dried, the crack is 3, after drying, the crack was four, compared to when the coating thickness is 0.3mm greater crack resistance coatings; cold and hot conditions are easy ingot stripping, thermal stripping, the ingot surface coating less attached to reduce the workload of ingot surface cleaning, coating not melt, reduces the thermal shock suffered ingot mold to protect the ingot mold; of coated high temperature strength with time and temperature to simulate the change the thermal environment of large steel ingot casting, the results show that the combination of magnesium phosphate inorganic silica coating and double coating adhesive bonded magnesia casting of large ingots basic to adapt.