Speaker
Description
The paper presents the results of research aimed at developing molding sand for manufacturing large-size iron castings using the Full Mold technology. Ultimately, the sand will be used to manufacture castings from a new type of ductile iron. Due to the specific properties of the castings, it was decided that the optimum sand should feature:
- appropriate shape and size of fresh sand/reclaim sand grain;
- the permissible level of dust;
- optimum selection of resin and hardener to ensure sand with a working life of 30–40 minutes and bending strength of 3–4 MPa;
- optimum permeability;
- optimum losses on ignition;
- optimum parameters of thermal decomposition in terms of knock-out and reclamation.
The research made it possible to determine the strength and permeability of the molding sand as a function of the content of resins and hardeners. The tests of sand strength and losses after a thermal cycle allowed us to estimate the knock-out properties and to create an innovative method for its quantitative characterization. The analysis of dust content impact in the sand reclaim used on sand strength made it possible to determine its maximum share. The project has resulted in the development of a composition consisting of 65% quartz sand reclaim, 35% fresh sand, 1.25% furan resin, and 0.4375% hardener. It makes it possible to manufacture molding sand optimum for the process, with a tensile strength after 48 hours Rg48 = 3.5 MPa. The obtained sand life of 55 minutes is sufficient. The limit content of dust in sand reclaim is about 0.81%, a higher share may make it difficult to achieve the required results. The molding sand developed shows good knock-out properties. The trial showed no penetration or burns of the molding sand and surface quality at a satisfactory level.
Acknowledgment
The research results described in this article were created in connection with the implementation of a research and development project entitled "Development of an innovative manufacturing technology for large-size castings made of nodular iron with special properties in Full Mold technology, dedicated to the production of stamping tools in the automotive sector" for which ODLEWNIA RAFAMET Sp. z o. o. signed a co-financing agreement number: POIR.01.01.01-00-0013 / 20-00 under the Intelligent Development Operational Program 2014-2020, Sub-action 1.1.1.
The research results described in this article were developed as part of the cooperation of the ODLEWNIA RAFAMET Sp. z o. o. with the Silesian University of Technology, Faculty of Mechanical Engineering.
| Speaker Country | Poland |
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