Basic Analysis for Gray Iron Thermal Analysis

At the Basic level all tests in the Simple Basic are included as well. The same rules on licensing apply to each level so if this screen is green, you can use these tests.To be a full featured system, MeltLab includes tests the never show up in your material. The Graphic Liquidus (Graf Liq) may never show up if you keep your C.E. below a 4.3. But if you do see it, MeltLab will tell you how much graphite expansion you lost back into your risers. Yes, some people still make solid risers and don’t know why. MeltLab does and tells you about it

Basic Option Curves for Gray Iron Microanalysis
These are the same as the Simple Basic options.
⦁ Temperature Curve is the basic data gathered by the thermal couple.
⦁ Cooling Rate Curve is the instantaneous change in temperature. For mathematicians, this is the first derivative inverted. This visual occupies the lower 25% of the curve window.
⦁ The Lard Cooling option gives the Cooling Rate curve 50% of the curve window.
⦁ For maximum size of the Cooling rate curve, simply click off the Temperature curve and the Cooling rate will occupy the entire window.
These options suggest that the Cooling Rate curve is very important, and it is. Details of arrests are much clearer in the Rate of Cooling due to magnification. The Temperature curve may span 300 degrees while the rate of cooling spans only 10 degrees – a magnification of 30x.

Information and Variables for Basic in Gray Iron Microanalysis
⦁ Austenite C.E. is calculated from the normal austenite liquidus.
⦁ Graphite Liquidus is a weaker arrest that only occurs if the C.E. goes too high. Some of your detection limits may need adjusting to pick this out.
⦁ Carbon lost is the difference between the graphitic C.E. and the Austenite C.E. assuming both occurred. An iron showing a graphite C.E. pf 4.50 and an austenite C.E. of 4.20 will make about 0.30 percent graphite in the liquid iron before the gates freeze off. This pushes iron back out the gates and into the risers. When the graphite liquidus finally stops the carbon-content has fallen lower than what might be expected, and the iron is usually several points below eutectic composition. Please note that this is an uncommon situation that generally does not occur. Because we have better control over our chemistry.
⦁ Eutectic undercooling is the lowest temperature before the eutectic arrest. Generally, some undercooling is needed to get the eutectic solidification started. Inoculation tends to raise this temperature.
⦁ Eutectic growth temperature is the highest temperature in the eutectic arrest. This is also the liquids temperature. Some people experiment with small cups or accelerated cooling and end up suppressing (pushing down) the liquidus value. Standard cups have been sized large enough to prevent suppressing. There are some ways to tell by looking closely at the curve if this has occurred.
⦁ Eutectic Recalescence is how much reheating has occurred due to the eutectic arrest. Recalescence is the Eutectic Temperature – the Eutectic Undercooling Temperature. Typical readings vary with the casting thickness. Thinner castings generally have more inoculation and thus less recalescence. This also depends on the type of inoculant being used which will depend on the casting shape and the properties needed.
⦁ End of Grain Boundary Stress is when the grain boundaries are fully solidified. The lower this temperature is, the longer any heat-treating will take.
⦁ Lance Temperature is only for systems that have temperature lances included with their MeltLab. It causes the most recent temperature lance reading to be included in the sample report.

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