Growing emission requirements are forcing the foundry industry to seek new, more environmentally friendly solutions. One of the
solutions may be the technologies of preparing moulding and core sands using organic biodegradable materials
as binders. However, not only environmental requirements grow but also those related to the technological properties
of moulding sand. Advancing automation and mechanization of the foundry industry brings new challenges related to the moulding sands.
Low elasticity may cause defects during assembly of cores or moulds by the manipulators.
The paper presents the study of flexibility in the room temperature according to new method and resistance to thermal deformation of selfhardening
moulding sands with furfuryl resin, containing biodegradable material PCL. The task of the new additive is to reduce the
moulding sands harmfulness to the environment and increase its flexibility in the room temperature. The impact of the additive and the
effect of the amount of binder on the properties of mentioned moulding sands were analysed. Studies have shown that the use of 5% of
PCL does not change the nature of the thermal deformation curve, improves the bending strength of tested moulding mixtures and
increases their flexibility at room temperature.
The article shows the influence of environment requirements on changes in different foundry moulding sands technologies such as cold
box, self-hardening moulding sands and green sands. The aim of the article is to show the possibility of using the biodegradable materials
as binders (or parts of binders’ compositions) for foundry moulding and core sands. The authors concentrated on the possibility of
preparing new binders consisting of typical synthetic resins - commonly used in foundry practice - and biodegradable materials. According
to own research it is presumed that using biodegradable materials as a part of new binders’ compositions may cause not only lower toxicity
and better ability to reclaim, but may also accelerate the biodegradation rate of used binders. What’s more, using some kinds of
biodegradable materials may improve flexibility of moulding sands with polymeric binder. The conducted research was introductory and
took into account bending strength and thermal properties of furan moulding sands with biodegradable material (PCL). The research
proved that new biodegradable additive did not decrease the tested properties.
This paper focuses on mechanical properties of self hardening moulding sands with furfuryl and alkyd binders. Elasticity as a new
parameter of moulding sands is investigated. With the use of presented testing equipment, it is possible to determine force kinetics and
deformation of moulding sand in real time. The need for this kind of study comes from the modern casting industry. New foundries can be
characterized with high intensity of production which is correlated with high level of mechanization and automatization of foundry
processes. The increasingly common use of manipulators in production of moulds and cores can lead to generation of new types of flaws,
caused by breakage in moulds and cores which could occur during mould assembly. Hence it is required that moulds and cores have high
resistance to those kinds of factors, attributing it with the phenomenon of elasticity. The article describes the theoretical basis of this
property, presents methods of measuring and continues earlier research.
A cast iron is gradient material. This means that depending on the cooling rate it is possible, at the same chemical composition and the physicochemical state of molten metal, to obtain material with a different structure. The connection between the wall thickness of the casting and the speed of its cooling expresses the casting module. Along with the module escalation a cooling rate of the casting is reducing what can cause changes of the microstructure and the increased tendency to the crystallization of distorted graphite forms. Inspections of experimental castings from nodular cast iron with different modules were conducted to the graphite form.
Modern techniques of castings production, including moulding sands production, require a strict technological regime and high quality
materials. In the case of self-hardening moulding sands with synthetic binders those requirements apply mainly to sand, which adds to
more than 98% of the whole moulding sand mixture. The factors that affect the quality of the moulding sands are both chemical (SiO2
,
Fe2O3 and carbonates content) and physical. Among these factors somewhat less attention is paid to the granulometric composition of the
sands. As a part of this study, the effect of sand quality on bending strength Rgu
and thermal deformation of self-hardening moulding sands
with furfural and alkyd resin was assessed. Moulding sands with furfural resin are known [1] to be the most susceptible to the sand quality.
A negative effect on its properties has, among others, high content of clay binder and so-called subgrains (fraction smaller than 0,1mm),
which can lead to neutralization of acidic hardeners (in the case of moulding sands with furfuryl resin) and also increase the specific
surface, what forces greater amount of binding agents. The research used 5 different quartz sands originating from different sources and
characterized with different grain composition and different clay binder content.
The paper presents possibility of using biodegradable materials as parts of moulding sands’ binders based on commonly used in foundry
practice resins. The authors focus on thermal destruction of binding materials and thermal deformation of moulding sands with tested
materials. All the research is conducted for the biodegradable material and two typical resins separately. The point of the article is to show
if tested materials are compatible from thermal destruction and thermal deformation points of view. It was proved that tested materials
characterized with similar thermal destruction but thermal deformation of moulding sands with those binders was different.
The constant growth of foundry modernization, mechanization and automation is followed with growing requirements for the quality and parameters of both moulding and core sands. Due to this changes it is necessary to widen the requirements for the parameters used for their quality evaluation by widening the testing of the moulding and core sands with the measurement of their resistance to mechanical deformation (further called elasticity). Following article covers measurements of this parameter in chosen moulding and core sands with different types of binders. It focuses on the differences in elasticity, bending strength and type of bond destruction (adhesive/cohesive) between different mixtures, and its connection to the applied bonding agent. Moulding and cores sands on which the most focus is placed on are primarily the self-hardening moulding sands with organic and inorganic binders, belonging to the group of universal applications (used as both moulding and core sands) and mixtures used in cold-box technology.
The article takes into consideration the researches concerning inserting the Glassex additive to the microwaved-hardened and selfhardened moulding sands with water glass. In the research different types of ester hardeners to self-hardened moulding sands with water glass were used. The influence of Glassex additive on retained strength of moulding sands with different hardeners and prepared by different technologies of hardening were tested. The influence of different hardeners and the technology of hardening on retained strength of moulding sand with water glass and the Glassex additive were also estimated.