The paper includes the TG-DTG thermogravimetric air-testing of a cellulose mixture modified with the additives of expanded vermiculite or expanded perlite. A thermal degradation test was carried out at 1000°C with a simultaneous qualitative analysis of the emitted gases. During the thermal degradation process, the thermal effects were also measured. The research results indicate that expanded vermiculite or expanded perlite do not emit toxic gases during thermal degradation. The cellulose mixture modification, with the additives of expanded vermiculite or perlite, does not result in the creation of new gaseous compounds in the process of thermal degradation. A s investigated below, the mixtures tested in this article find application in gating systems for supplying liquid metal in no-bake moulds. Such cellulose-based material solutions shall allow the foundry industry to introduce less gas vaporising technologies within the entire casting production process.
This paper presents the findings of a study of gas emissivity and the volumetric gas flow rate from a patented modified cellulose mix used
in production of disposable sand casting moulds. The modified cellulose mix with such additives as expanded perlite, expanded
vermiculite and microspheres was used as the study material. The results for gas emissivity and the gas flow rate for the modified cellulose
mix were compared with the gas emissivity of the commercial material used in gating systems in disposable sand casting moulds. The
results have shown that the modified cellulose mix is characterized by a lower gas emissivity by as much as 50% and lower gas flow rate
per unit mass during the process of thermal degradation at the temperature of 900°C, compared to the commercial mix. It was also noted
that the amount of microspheres considerably affected the amount of gas produced.
The herein paper contains the results of investigations on a new type of cellulose blend used for the manufacture of profiles applied in the
process of making gating systems in the foundry industry. A standard cellulose profile was subjected to an experiment. During the
experiment the profile was filled with a liquid cast iron and at the same time the temperatures of the liquid metal crystallizing inside the
profile were measured as well as the temperature of the outer layer of the profile was controlled. Further, the microstructure of the cast
iron, which crystallized out inside the cellulose profile, was analysed and the cellulose, thermally degraded after the experiment, was
verified with the use of the chemical analysis method. Moreover, a quality analysis of the original as well as the degraded cellulose profile
was run with the use of the FTIR infrared spectroscopy. The presented results revealed that the cellulose blend is aluminium silicate
enriched and contains organic binder additives. The cast iron, which crystallized out, tended to have an equilibrium pearlitic structure with
the release of graphite and carbides. The generation of disequilibrium ausferrite phases was also observed in the structure.
This paper presents the findings of fatigue strength tests of 15CrNi6 steel following low-pressure carburizing and oil quenching, subjected to cycles of one-sided three-point bending. The fatigue fractures were compared with the results of fatigue strength studies of 16MnCr5 steel following low-pressure carburizing and nitrogen quenching. The fatigue tests for 16MnCr5 steel were conducted as part of a high-cycle resonance test, with a pendular bending load. The study also involved an analysis of the effects on non-metallic inclusions in the structure on the mechanism of fatigue destruction. The inclusions were found to initiate fatigue cracks. In both cases, a similar method of a fatigue fissure initiation was observed, independent of the study method or specimen material.
Twist extrusion is a processing method involving the extrusion of a sample with a prismatic cross-section using a tool composed of four prismatic parts bisected by a screw component. A beneficial change in mechanical durability is one of the main factors enabling the use of highly durable Al-Mg-Mn-Sc-Zr alloys to construct functional components of non-stationary robots. As part of the present research, ANSYS® software was used to simulate a twist extrusion process. An analysis of a sample entering and passing through the entire twisting area was performed, up to the point of full twisting of the base of the sample. The stress conditions in the sample were analysed as it passed through the twisting area. The highest stress values (reaching up to 600 MPa) were detected at the tips of the sample face as the sample exited the twisting area. The lowest stress values, at around 170 MPa, were detected at the side edges of the sample.