The Impact of Process Factors on Creating Defects, Mainly Lustrous Carbon, during the Production of Ductile Iron Using the Lost-Foam Casting (LFC) Method

Abstract

The purpose of this paper was to analyze the process factors affecting the occurrence of lustrous carbon defects in ductile cast iron castings when using the lost-foam casting (LFC) method. This phenomenon results in creating raw surface defects, which sometimes may even lead to cast iron scrapping. A series of trial melting batches were carried out for variable process assumptions. The analysis was performed to reflect, to the greatest extent possible, real foundry production conditions. Industrial tests were performed in Odlewnia Rafamet Sp. z o.o., Kuźnia Raciborska, Poland. The polystyrene patterns created by gluing components together, used in the tests, met the requirements of the high-tech lost-foam casting (LFC) process. The performed analysis allowed the obtaining of lustrous carbon defects in test castings as well as the determination of the process parameters with the highest impact on lustrous carbon inclusions in ductile iron castings. The test results were used to eliminate the possibility of creating a defect and thus directly improve the efficiency of the lost-foam casting (LFC) process used in the foundry.

Innovative Inorganic Binder Systems for the Production of Cores for Non-Ferrous Metal Alloys Reflecting the Product Quality Requirements

“…As is generally known, the high proportion of fine particles must be compensated by an increased dosage of binder (as the size of the individual particles decreases, the total surface area of the sand increases significantly, thus increasing the consumption of binder to achieve the required strengths). However, this could have a negative effect on the gas regime of the mold (core)-metal system and the tendency to gas defects formation [15]. On the other hand, a required surface quality of the casting is generally ensured and the potential for metal penetration types of casting defects was significantly eliminated.…”

Effects of mechanical vibration on filling and solidification behavior, microstructure and performance of Al/Mg bimetal by lost foam compound casting

“…It can be found that the filling speed is fast at first and then slow throughout the filling process, and the liquid metal takes a total of 2.2 s to fill the cavity. Another interesting phenomenon is that the liquid metal fills the cavity in a concave shape, which is called the wall attachment effect, which is commonly seen in the filling process of the LFC under high vacuum [39,45] . However, the introduction of the A356 inlay produces some different phenomena.…”