raw materials for castings
In order to get high quality cast iron will need high quality raw materials, there will related to several different raw materials for casting (foundry).
Firstly, about the recarburizer, because of different raw materials and the content of carbon, sulfur and nitrogen, it can be divided into different types such as CPC (calcined petroleum coke),GPC (graphitized petroleum coke), CAC (calcined anthracite carbon), graphite carbon etc, the carbon content of CPC is more than 98% or 98.5%, sulfur content is not more than 0.5%, and for the GPC as the best quality recarburizer, the carbon content is more than 98.5% and sulfur content is not more than 0.05%, what is more, nitrogen content is just 300PPM. For different castings will need different recarburizer, if want to use for gray cast iron, then the CPC will be enough because of the cheap price and compared effective effect. If want to use for ductile cast iron, then the graphite carbon will be proper because of the lower sulfur and nitrogen than CPC. As for the GPC, it is one type of best recarburizer in low sulfur and low nitrogen, so it can be used for the gray cast iron and ductile cast iron, in order to produce qualified cast iron, so need to choose proper recarburizer at first.
Secondly, about the inoculant, though the added amount of inoculant is small, and has little influence on the chemical composition of cast iron, but it make big influence on the micro-structure of cast iron, cast iron with good inoculation will has good fluidity, reduces shrinkage of castings, improves processing performance, and reduces residual stress. There are generally two types of the inoculation, one is ladle inoculant, in generally, ladle less than 300kg can choose the size 0.5mm to 3mm, and ladle more than 300kg is recommended to choose the size 1-5mm, when inoculating ductile cast iron, it is very important that the inoculant must be added after Mg reaction is completed. Adding together with the spheroidizing agent or adding it when the reaction is taking place will greatly reduce the effectiveness of the inoculant and may lead to an increase in the carbide content of the casting. In the case that the spheroidizing agent and the inoculant must be added to the same ladle, when about 2/3 of the molten iron has been poured on the spheroidizing agent the iron should be stopped. Then wait until the reaction is over, and then add the inoculant to the remaining molten iron stream. The other generally is the in-flow inoculant, compared with the conventional ladle processing, the amount of inoculant added can be greatly reduce. Under normal circumstances, the amount of gray iron is 0.02-0.05%, and the amount of ductile iron is 0.05%-0.2%, in general, the particle size of the inoculant must be specifically set at 0.2-0.7mm to ensure its rapid dissolution in molten iron and good fluidity through the application of machinery. The effect of all inoculants will decline over time, so in order to obtain the greatest effect, casting should be carried out as soon as possible after the inoculation treatment, it is best to add the inoculant to the casting stream.
Thirdly will talk about the spheroidizing agent, the magnesium content of 4%, 5% or 5.5% belongs to low magnesium spheroidizing agent, and the RE is between 1%-2%, which is mostly used for smelting in intermediate frequency furnace and spheroidizing of low sulfur molten iron, it has the advantage of gentle spheroidization reaction and easy absorption of spheroidizing elements. The magnesium content of 6% or 7% belongs to the medium magnesium series spheroidizing agent, which is mostly used for double smelting in cupola and electric furnace, or smelting pearlite cast iron castings in intermediate frequency furnace. High magnesium type suitable for cupola smelting, sulfur content of 0.06%-0.09% of molten iron, and the addition amount is between 1.6%-2.0%.
Anyang Huauto Metallurgy Co.,Ltd has in the raw materials for casting or foundry for more than 10 years, can supply various recarburizer, spheroidizing agent, inoculant etc materials in different size as requirement, glad to receive your contact.