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Ways to Avoid Molten Metal Explosions
A proper safety plan for potential physical explosions can save lives and prevent huge fi nancial loss.
American Foundry Society 10-Q Safety and Health Committee, Schaumburg, Ill. Fred Kohloff, American Foundry Society, Schaumburg, Ill.
olten metal explosions can occur without warning in metalcasting facilities and throw molten metal and high-temperature solids throughout the surround- ing area, putting workers, equipment and nearby building structures at risk. These explosions can
cause fatalities, serious burns and extensive property damage. The major cause of explosions is the entrapment of liq-
uid, water or moisture beneath the surface of molten metal. When this occurs, hot particles of molten metal become fi nely dispersed in water or moisture and instantaneously turn to steam or vapor. The rapid heat transfer from the hot particles to the water can cause a violent explosion. Water, the most common cause of molten metal explosions, expands to 1,600 times its original volume. The violence of an explosion depends on the quantity
of liquid and the rate of energy released, coupled with the amount of molten metal that has encapsulated the liquid. Dangerous incidents, such as spitting, splashing or explo-
sions, although infrequent, occur in steel, iron and nonfer- rous metalcasting facilities due to several reasons, including:
• lack of proper inspection of charge materials for liquids or moisture prior to charging;
• accidental rupture of furnace cooling; • accidental rupture of furnace hydraulic lines; • erroneously charging sealed drums, containers and tubing/ piping containing water or liquid directly into the furnace;
• spilling molten metal or slag into a pit or onto a fl oor contain- ing water, moisture or other liquids (e.g. hydraulic fl uids);
• erroneously using wet, cold or rusted tools in the furnace • furnace bridging; • poor installation of new furnace lining where sintering protocol was not followed;
• poor furnace maintenance; • inadequate drying of ladles after relining; • erroneously allowing uncontrolled water sources in the melt area. However, metalcasting facilities can take precautions
to reduce the risk of molten metal explosions. Following are 21 areas to consider for safe management of potential explosion hazards.
MODERN CASTING / July 2010
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