Shield type coating composition and preparation process of coating thereof

Abstract

The invention discloses a shield type coating composition, comprising a fire-proof powder mixture, a suspending agent, a binder and a carrier fluid, wherein the fire-proof powder composition consists of high temperature resistant components and functional components, and has a particle size of 200-325 meshes. The invention selects a reasonable fire-proof powder composition to prepare the shield type sand coating, thus achieving good sand burning resistance, and preventing the defects of recarburization on extra-low-carbon stainless steel piece surface and desulphurization on nodular cast iron piece surface, thereby realizing the aim of ensuring casting quality.

Description

Technical field: [0001] The invention relates to an auxiliary material for casting molding, in particular to a shielding coating composition for sand casting and a preparation process of the coating. Background technique: [0002] Sand mold coating is a thin layer of refractory coating applied on the surface of sand mold (core), usually composed of refractory powder, carrier, suspending agent, binder and other components. Among them, the refractory powder is the basis of the coating, which is suspended in the coating by means of a suspending agent, and the coating is evenly coated on the working surface of the sand mold (core). After the carrier liquid volatilizes, the binder makes the refractory powder dry and form Dense coating. The use of sand coating can change and control the contact state between the molten metal and the sand (core) interface and the reaction at high temperature to prevent the occurrence of various defects, thereby significantly improving the surface ...

AI Technical Summary

Problems solved by technology

[0003] Using organic binder sand to produce ultra-low carbon stainless steel parts, the biggest problem is the increase of carbon on the surface of the casting, which will lead to a decrease in the corrosion resistance and fatigue resistance of the casting, and make the welding performance worse

In order to solve the problem of carburizing the surface of ultra-low carbon stainless steel parts, water glass sand is currently used for molding, and the surface of the mold (core) is coated with a common commercially available zirconium powder alcohol-based coating, and then the common commercially available zirconium powder is applied after being ignited and dried. British powder water-based coating is dried, but it is still difficult to accurately control the coating quality in production, so that the purpose of anti-carburization cannot be achieved

[0004] When furan resin-toluenesulfonic acid sand mold is used to produce ductile iron castings, the toluenesulfonic acid in the resin sand at the casting-sand mold interface is decomposed by heat, and the sulfur-containing gas produced will be with magnesium and rare earth, etc., which have strong affinity with sulfur in the unsolidified metal liquid. It reacts to form sulfide, which leads to poor spheroidization of the surface of ductile iron castings, resulting in a decline in casting quality

The ordinary commercially available cast iron graphite alcohol-based coatings used in actual production cannot prevent sulfurization. Generally, the abnormal structure can be reduced by increasing the amount of nodularizer or using a curing agent without sulfonic acid, but the former will greatly increase the production cost. The latter will lead to poor sand performance and other defects