Thermodynamic stability of austenitic Ni-Mn-Cu cast iron

The performed research was aimed at determining thermodynamic stability of structures of Ni-Mn-Cu cast iron castings. Examined were 35 alloys. The castings were tempered at 900 °C for 2 hours. Two cooling speeds were used: furnace-cooling and water-cooling. In the alloys with the nickel equivalent value less than 20,0 %, partial transition of austenite to martensite took place. The austenite decomposition ratio and the related growth of hardness was higher for smaller nickel equivalent value and was clearly larger in annealed castings than in hardened ones. Obtaining thermodynamically stable structure of castings requires larger than 20,0 % value of the nickel equivalent

Stanowisko badawcze do oceny efektów utwardzania mas ze szkłem wodnym

W pracy przedstawiono wyniki badań nad możliwością zastosowania nowego stanowiska badawczego do oceny, na podstawie końcowejzawartości wody, finalnego efektu utwardzania wybranymi metodami mas ze szkłem wodnym. Badania wykonano na innowacyjnym,mobilnym stanowisku mikrofalowej linii szczelinowej wykorzystującej zjawisko występowania fali stojącej w falowodzie. Badaniompoddano pięć mas sporządzonych z dostępnymi w handlu gatunkami szkła wodnego, które utwardzano trzema, wybranymi metodami:mikrofalową, klasyczną oraz w procesie CO2. Wykazano, na przykładzie mas ze szkłem wodnym, że prezentowane, mobilne stanowiskopomiarowe może, na podstawie określenia końcowej zawartości wody, służyć z powodzeniem do oceny ostatecznego efektu utwardzaniamas formierskich i rdzeniowych

Determination of the binder in sand molds with the use of microwaves

The paper presents results of preliminary examinations of possibility to measure binder content in traditional moulding sands using a new method employing electromagnetic waves. The presented examinations were carried-out with use of an innovative test station, the so-called microwave slot line. The measurements of binder content in moulding sand were based on the results of power balance investigation of microwaves affecting the specimen. An advantage of the suggested, new method of binder content measurement is short measuring time

Possibilities of using microwave heating in disposal process of thermo and selfsetting sandmixes

The paper presents a semi-industrial reactor designed for microwave utilization of waste moulds and cores made of moulding sands prepared in furane resin technology. It was found that a possibility exists of effective incinerating this way prepared residues of cores separated from moulding sands or waste moulds left after casting. The preliminary tests evidenced that microwave heating is an effective way of disposing waste moulding sands and the applied apparatus permits effective control of the microwave heating process

Effectiveness of Absorbing Microwaves by the Multimaterial Sodium Silicate Base Sand - PLA (Polylactide) Mould Wall Systems

In the paper presented are results of a research on effectiveness of absorbing electromagnetic waves at frequency 2.45 GHz by unhardened sodium silicate base sands (SSBS) prepared of high-silica base sand and a PLA (Polylactide) 3D-prited (3DP) mould walls. Measurements of power loss of microwave radiation (P in) expressed by a total of absorbed power (P abs), output power (P out) and reflected power (P ref) were carried-out on a stand of semiautomatic microwave slot line for determining balance of microwave power emitted into selected multimaterial systems. Values of microwave power loss in the rectangular waveguide filled with unhardened moulding sands and prepared by fused deposition modelling (FDM) 5 mm polylactide (PLA) walls with grid infill density from 25% to c.a. 100% served for determining effectiveness of microwave heating. Balance of microwave power loss is of technological importance for microwave manufacture of high-quality casting sand moulds and cores in possibility of use 3D-printed mould tools and core boxes. It was found that apparent density of SSBS placed in a waveguide with PLA walls influences parameters of power output (P out) and power reflected (P ref). The PLA wall position and grid infill density were identified to have a limited effect on effectiveness of absorbing microwaves (P abs)