14-15#04 Influence of Mn & S on the Microstructure of Cast Iron
Principal Investigator: Richard Gundlach, Element Materials Technology
Steering Committee Chair: Leonard Winardi, Charlotte Pipe & Foundry Co.
A recent literature review suggested that, to achieve optimum strength and resistance to chill in cast iron, Mn and S should be balanced according to MnS solubility. When the chemistry is adjusted such that the limit of MnS solubility in the melt occurs at, or near the eutectic temperature, strength is maximized.
The objective of this project was to characterize the relationship between S, Mn and the graphite structure of cast iron in a wide range of section sizes. Additionally, this project further looked into the correlation between Mn, S and section within the size of eutectic cell.
Library Paper Number: 18-091
15-16#01 Veining Reduction Project – Phase II
Principal Investigator: Sam Ramrattan, Western Michigan University
Steering Committee Chair: Fritz Meyer, ASK Chemicals
Foundry engineers have long known that there is high test-to-test variability with certain precision sand specimen. In a Phase I simulation analysis was used to improve a tool design for producing 50 mm, 8 mm thick polyurethane cold-box (PUCB) disc-shaped specimens. Ramrattan et al. (2014) identified uniformity in sand binder density distribution in PUCB specimens. A new tool was built according to recommendation from the simulation and specimens were produced. Physical, mechanical, and thermo-mechanical testing was conducted on the new specimens and compared to old. The results show that there is lower test-to-test variability with the new disc-shaped specimens.
The purpose of this project was to determine whether the models can be used for predicting the onset of veining and penetration.
Library Paper Number: 18-036
16-17#04 Pre-firing Time/ Temperature Effect on Investment Shell Thermo-Mechanical Properties
Principal Investigator: Mingzhi Xu, Missouri University of Science and Technology
Steering Committee Chair: Matt Cavins, O’Fallon Casting
Investment shells are typically prefired before being poured. In the steel industry, the prefiring temperature is generally high enough to trigger some amount of devitrification of the amorphous silica constituent in the shell molds. Different foundries have their own prefiring temperature/time profiles which result in different amount of devitrification, thus affecting the thermo-mechanical properties of the shell molds. Estimating thermal properties from handbook data without considering the phase changes during the process is usually inaccurate. Applying thermal property values from commonly used simulation software database without carefully considering the difference of prefiring regime will often not represent the reality.
The ultimate objective of this project was to establish a kinetic model that predicts the thermo-mechanical properties of silica based investment shells.
Library Paper Number: 18-050
16-17#07 Effect of Water Quality on Green Sand Properties
Principal Investigator: Bo Wallace, University of Northern Iowa
Steering Committee Chair: Matt Calcutt, Rochester Metal Products
Water-soluble salts or electrolytes are just some of the mineral contaminants that are found in everyday tap water used by foundries across the U.S for their green sand systems, which primarily contain sand, bentonite, cereal, and water. Bentonite is the main bonding compound of the green sand, and for it to have quality bonding, it first must be activated with the use of an agent. A good activating agent must fulfil three requirements. Twenty (20) water samples were brought in from around the country from foundries that use well water for their green sand water source. These samples were analyzed using an Inductive Coupled Plasma (ICP) spectrometer for determining the electrolytic salts concentrations. The physical properties of green sand prepared using the water samples was characterized using baseline green sand testing in order to evaluate the effect of salts on properties.
Library Paper Number: 18-009
17-18#03 Influence of Mn-S Balancing on Fatigue Strength in Cast Iron
Principal Investigator: Richard Gundlach, Element Materials Technology
Steering Committee Chair: Matt Meyer, Kohler
Sulfur is generally considered a tramp element in cast iron, and its level must be controlled. When manganese is not present at sufficient concentrations, sulfur reacts with iron to produce a low-melting phase that can produce hot-shortness in iron castings. Consequently, the industry has always added Mn to control S in cast iron. Various formulae have been promulgated in the industry for balancing Mn and S. Many employ a stoichiometric relationship between Mn and S, requiring an excess Mn content to avoid FeS formation. Some simply employ a Mn to S ratio (such as 5 – 7) to assure that no FeS forms. Others advocate that the sulfur content must simply be at or above 0.04%S to obtain adequate inoculation response.
The goal of this project was to characterize the stress-life fatigue properties of high and low strength regions of one Mn series from an earlier AFS study.
Library Paper Number: 18-094