Basic Study On The Processing Properties Of Environment Friendly Molding Sand

Sand casting process is one of main casting process.Molding sand is resourceful and low cost and it is essential molding material during the sand casting process.As the molding material of sand casting process,clay sand which used clay as agglomerate is historical.And green sand is the most widely-used molding sand because of it's convenient molding and high production efficiency.Add coal dust to green sand which is world widely used leads to the problems of high consumption of new sand?flue gas and high-emission of waste sand.That is polluted seriously and not suitable for the scientific development of foundry industry and the environmental protection policy of energy saving and emission reduction any more.The greenization of molding material is urgent.The key to achieve green casting is green and clean production of sand casting process.Environment friendly molding sand is fully composed of inorganic material,the sand is researched cooperatively by Dong Hua university and enterprise.It is new method to achieve green casting with pretty nice performance of casting process?release no toxic gases?high recovery rate of molding sand and the environment-friendly waste sand.This article do research on the performance of casting process of environment friendly molding sand by adjusting the formula of the sand.Above all,this paper presents the effect of additives on the properties of quartz sand based environment friendly molding sand.Firstly,the performance of the environment friendly molding sand with same formula during three different sand mixing processes has been studied.Secondly,the normal temperature properties and thermal properties of environment friendly molding sand with different contents of clay No.1,water,clay additive No.1 and Refractories Mortar have been studied by orthogonal experiment.Also wet compressing strength,permeability and hot wet tensile strength of molding sand have been tested.Accordingly,this paper describes the effect of these four factors on the processing property of molding sand.Finally,the influence of various factors on the hot compressing strength of molding sand has been tested by high temperatureexperiments.The results show that the sand with good performance and stability can be obtained quickly by adding water ahead of adding clay which improves production efficiency.The content of clay No.1 is the main factor that affects the strength and permeability of environment friendly molding sand.The high temperature hot compressing strength of molding sand can be increased by increasing the content of clay No.1,clay additive No.1 and Refractories Mortar,and Refractories Mortar is the most significant factor.Then,this paper also presents the study on the performance of No.2 yellow loam sand based environment friendly molding sand.The processing property of molding sand with different ratios of No.2 yellow loam sand and quartz sand has been studied.Through orthogonal experiment,the effect of No.2 yellow loam sand and quartz sand ratio,water,clay additive No.1 contents on the wet compressing strength and permeability have been founded.Also,this paper analyses the relationship between the No.2 yellow loam sand and quartz sand ratio and sinter layer property.The results show that the No.2 yellow loam sand and quartz sand ratio is the main factor that affects wet compressing strength,permeability and wet tensile strength,while water content is the main factor of the cok Paction.The smaller the quartz sand ratio is,the more serious the sand sintering is,meanwhile the comprehensive performance can be the best with the ratio of No.2yellow loam sand and quartz sandis 4:6.Finally,this paper presents the analysis about the change of casting performance of environment friendly molding sand.The form changes are observed when sand heated by hot stage polarized optical microscopy.The changes of performance of sand in different burning temperature are explained by Thermogravimetric Analysis and Differential Scanning Calorimetry.The results show that the low melting point minerals on the surface of environment friendly molding sand can be sintered to glass phase at high temperature,a part of the glass phase is preserved when cooled to room temperature.The loss of material content is small after burning,re-use requires to add less material and reduces the consumption of raw materials.