Simple Solutions That Work! Issue 13

DEFECT PREVENTION 25 Figure 1: Grit box filter for a dip well Figure 2: In-line 8 grit filter for a machine side melter or launder system Contact: RICHIE HUMPHREY [email protected] We feel everyone should filter their metal either with a box filter ( Figure 1 ) or an in-line filter ( Figure 2 ). With the possible exception of electric melter (and even those if your are returning scrap metal into them or making aircraft quality parts), every furnace made to melt aluminum will produce some inclusions. Furnaces that have flames touching the bath or solids on a hearth will absorb more hydrogen and products of combustion than those furnaces where the flame never touches the bath of aluminum or the scrap, ingots or sows. Filtration has the following benefits: 1. Filtration increases fluidity, possibly allowing you to reduce your casting temperature, which is better for molds and dies. 2. Helps reduce hydrogen trapped by inclusions. 3. It will reduce hard spot 90% of your inclusions 25 microns or greater and the more clogged the filter becomes the more finite the filtration. 4. If you design the filter into the furnace from the start it can be put in to make it easy to change. 5. Filters are good for 1-1.5 million pounds before they clog, depending upon how dirty the metal is coming into them. 6. Inexpensive way of reducing scrap! Filtration should be one of the first things you look at to correct inclusions and some hydrogen issues. I can think of no better way to prevent defects than to supply your casting process with the most pristine/cleanest metal to run parts in their process.