2016
14-15#02 Application of DSC Coupled with TGA and MS to Assess Sand Binder Emission
Principal Investigator: Scott Giese, University of Northern Iowa
Steering Committee Chair: Mitchell Patterson, HA International
Emissions of hazardous air pollutants and organic volatile components have been a major concern for the foundry industry in providing a safe work environment for their employees. Emission studies have evolved from the emission compound identification work performed during the 1990’s to the correlation of emission amounts per ton of metal poured conducted in the 2000’s, most notably, the extensive emission study perform by the defunct Casting Emission Reduction Program. Data collected and presented to the foundry by CERP provided critical information for developing binder technologies to address emission reductions in HAP’s and VOC’s.
The purpose of this project was to contribute with developing a low cost emission protocol to assess HAP and VOC release into the workplace environment. The research approach supported several research areas where emission analysis is critical; particularly for gas evolution in molds and cores to reduce gas related casting defects.
Library Paper Number: 17-098
14-15#08 Investigation of Cause of Microporosity of a low lead Cu-Based Alloy
Principal Investigator: Charles Monroe, University of Alabama Birmingham
Steering Committee Chair: Kerry Bisset, MAGMA Foundry Technologies Inc.
Micro-porosity is a hard defect to analyze because it is not easily seen. This defect is not normally found until the casting is tested for leaks. Proof of micro-porosity is generally proven through optical microscopy. It is also hard to pinpoint what causes micro-porosity and each individual casting whether there is increased air pressure, lack of feeding or other possible causes may have to be considered. These micro-pores can also cause detriments and strength or just overall losses in mechanical property. When a part has micro-porosity and it’s put under pressure, the micro-porosity can serve as a nucleation site for cracks. In copper alloys, where they are mainly used for plumbing applications, this pressure tightness is a mandatory factor, so micro-porosity must be eliminated.
The purpose of this project was to understand the mechanism and possible critical values that should be avoided in creating micro-porosity.
Library Paper Number: 17-103
15-16#04 Prediction of Gas Evolution from Chemically Bonded Sand
Principal Investigator: Sairam Ravi, University of Northern Iowa
Steering Committee Chair:
Gas evolution from chemically bonded sand molds is of major interest to the foundry industry. It is known that considerable amounts of gases are evolved from sand molds and cores when molten metal is poured against them. The gas evolved, if not vented properly, may be absorbed in the metal before solidification, hence resulting in gas porosity in the casting.
It has been determined that gas bubbles can form when the internal core pressure exceeds the metal-head pressure, which occurs as soon as molten metal comes in contact with the core and volatilizes the binder. Depending on the permeability of the sand and the internal core pressure, these bubbles can be trapped in the casting as solidification of the metal occurs. However, currently, the technology to predict and simulate the gas evolution from resin-bonded cores using process simulation software packages is still in its initial stages.
The University of Northern Iowa Metal Casting Center developed a methodology to accurately measure gases evolved from chemically bonded sand using DSC-TGA techniques. The resulting gas evolution data can be used in conjunction with already published research on gas bubble formation in different alloys to predict gas bubble formation in different areas of the casting.
Library Paper Number: 17-097