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Title: Low Cost and Energy Efficient Methods for the Manufacture of Semi-Solid (SSM) Feedstock

Abstract

The SSM Consortium (now ACRC) at WPI has been carrying out fundamental, pre-competitive research in SSM for several years. Current and past research (at WPI) has generated many results of fundamental and applied nature, which are available to the SSM community. These include materials characterization, yield stress effects, alloy development, rheological properties, process modeling/simulation, semi-solid slurry formation, etc. Alternative method to produce SSM slurries at lower processing costs and with reduced energy consumption is a critical need. The production of low cost SSM feedstock will certainly lead to a dramatic increase in the tonnage of castings produced by SSM, and will provide end users such as the transportation industry, with lighter, cheaper and high performance materials. In this program, the research team has addressed three critical issues in semi-solid processing. They are: (1) Development of low cost, reliable slurry-on-demand approaches for semi-solid processing; (2) Application of the novel permanent grain refining technology-SiBloy for the manufacture of high-quality SSM feedstock, and (3) Development of computational and modeling tools for semi-solid processing to enhance SSM process control. Salient results from these studies are summarized and detailed in our final technical report.

Authors:
; ;
Publication Date:
Research Org.:
Worcester Polytechnic Institute
Sponsoring Org.:
USDOE Office of Energy Efficiency and Renewable Energy (EERE); USDOE Office of Industrial Technologies (OIT) - (EE-20)
OSTI Identifier:
859300
Report Number(s):
DOE/ID/14232
TRN: US200710%%103
DOE Contract Number:
FC36-02ID14232
Resource Type:
Technical Report
Country of Publication:
United States
Language:
English
Subject:
32 ENERGY CONSERVATION, CONSUMPTION, AND UTILIZATION; 36 MATERIALS SCIENCE; ALLOYS; CASTINGS; ENERGY CONSUMPTION; PERFORMANCE; PROCESS CONTROL; PROCESSING; PRODUCTION; REFINING; SIMULATION; SLURRIES; "Semi-Solid Processing"; "Feedstock"

Citation Formats

Diran Apelian, Qingyue Pan, and Makhlouf Makhlouf. Low Cost and Energy Efficient Methods for the Manufacture of Semi-Solid (SSM) Feedstock. United States: N. p., 2005. Web. doi:10.2172/859300.
Diran Apelian, Qingyue Pan, & Makhlouf Makhlouf. Low Cost and Energy Efficient Methods for the Manufacture of Semi-Solid (SSM) Feedstock. United States. doi:10.2172/859300.
Diran Apelian, Qingyue Pan, and Makhlouf Makhlouf. Mon . "Low Cost and Energy Efficient Methods for the Manufacture of Semi-Solid (SSM) Feedstock". United States. doi:10.2172/859300. https://www.osti.gov/servlets/purl/859300.
@article{osti_859300,
title = {Low Cost and Energy Efficient Methods for the Manufacture of Semi-Solid (SSM) Feedstock},
author = {Diran Apelian and Qingyue Pan and Makhlouf Makhlouf},
abstractNote = {The SSM Consortium (now ACRC) at WPI has been carrying out fundamental, pre-competitive research in SSM for several years. Current and past research (at WPI) has generated many results of fundamental and applied nature, which are available to the SSM community. These include materials characterization, yield stress effects, alloy development, rheological properties, process modeling/simulation, semi-solid slurry formation, etc. Alternative method to produce SSM slurries at lower processing costs and with reduced energy consumption is a critical need. The production of low cost SSM feedstock will certainly lead to a dramatic increase in the tonnage of castings produced by SSM, and will provide end users such as the transportation industry, with lighter, cheaper and high performance materials. In this program, the research team has addressed three critical issues in semi-solid processing. They are: (1) Development of low cost, reliable slurry-on-demand approaches for semi-solid processing; (2) Application of the novel permanent grain refining technology-SiBloy for the manufacture of high-quality SSM feedstock, and (3) Development of computational and modeling tools for semi-solid processing to enhance SSM process control. Salient results from these studies are summarized and detailed in our final technical report.},
doi = {10.2172/859300},
journal = {},
number = ,
volume = ,
place = {United States},
year = {Mon Nov 07 00:00:00 EST 2005},
month = {Mon Nov 07 00:00:00 EST 2005}
}

Technical Report:

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  • Semi-solid metal (SSM) processing has emerged as an attractive method for near-net-shape manufacturing due to the distinct advantages it holds over conventional near-net-shape forming technologies. These advantages include lower cycle time, increased die life, reduced porosity, reduced solidification shrinkage, improved mechanical properties, etc. SSM processing techniques can not only produce the complex dimensional details (e.g. thin-walled sections) associated with conventional high-pressure die castings, but also can produce high integrity castings currently attainable only with squeeze and low-pressure permanent mold casting processes. There are two primary semi-solid processing routes, (a) thixocasting and (b) rheocasting. In the thixocasting route, one starts frommore » a non-dendritic solid precursor material that is specially prepared by a primary aluminum manufacturer, using continuous casting methods. Upon reheating this material into the mushy (a.k.a. "two-phase") zone, a thixotropic slurry is formed, which becomes the feed for the casting operation. In the rheocasting route (a.k.a. "slurry-on-demand" or "SoD"), one starts from the liquid state, and the thixotropic slurry is formed directly from the melt via careful thermal management of the system; the slurry is subsequently fed into the die cavity. Of these two routes, rheocasting is favored in that there is no premium added to the billet cost, and the scrap recycling issues are alleviated. The CRP (Trade Marked) is a process where the molten metal flows through a reactor prior to casting. The role of the reactor is to ensure that copious nucleation takes place and that the nuclei are well distributed throughout the system prior to entering the casting cavity. The CRP (Trade Marked) has been successfully applied in hyper-eutectic Al-Si alloys (i.e., 390 alloy) where two liquids of equal or different compositions and temperatures are mixed in the reactor and creating a SSM slurry. The process has been mostly used for hypo-eutectic Al-Si alloys (i.e., 356, 357, etc.) where a single melt passes through the reactor. In addition, the CRP (Trade Marked) was designed to be flexible for thixocasting or rheocasting applications as well as batch or continuous casting. Variable heat extraction rates can be obtained by controlling either the superheat of the melt, the temperature of the channel system, or the temperature of the reactor. This program had four main objectives all of which were focused on a mechanistic understanding of the process in order to be able to scale it up, to develop it into a robust process,and for SSM processing to be commercially used.« less
  • This project sought and successfully answered two big challenges facing the creation of low-energy, cost-effective, zeotropic multi-component distillation processes: first, identification of an efficient search space that includes all the useful distillation configurations and no undesired configurations; second, development of an algorithm to search the space efficiently and generate an array of low-energy options for industrial multi-component mixtures. Such mixtures are found in large-scale chemical and petroleum plants. Commercialization of our results was addressed by building a user interface allowing practical application of our methods for industrial problems by anyone with basic knowledge of distillation for a given problem. Wemore » also provided our algorithm to a major U.S. Chemical Company for use by the practitioners. The successful execution of this program has provided methods and algorithms at the disposal of process engineers to readily generate low-energy solutions for a large class of multicomponent distillation problems in a typical chemical and petrochemical plant. In a petrochemical complex, the distillation trains within crude oil processing, hydrotreating units containing alkylation, isomerization, reformer, LPG (liquefied petroleum gas) and NGL (natural gas liquids) processing units can benefit from our results. Effluents from naphtha crackers and ethane-propane crackers typically contain mixtures of methane, ethylene, ethane, propylene, propane, butane and heavier hydrocarbons. We have shown that our systematic search method with a more complete search space, along with the optimization algorithm, has a potential to yield low-energy distillation configurations for all such applications with energy savings up to 50%.« less
  • The manual provides both lighting-standard guidelines and low-cost strategies to encourage energy cost control in new and existing Illinois state-building illumination systems. Such guidance should provide a better understanding of simple operations and maintenance changes that will result in significant savings of energy use and cost in Illinois state building utility expense.
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