>> Iron << Aluminum Steel Copper. MeltLab Systems Copyright 2014 All rights reserved 844-Meltlab

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1 >> Iron << Aluminum Steel Copper MeltLab Systems Copyright 2014 All rights reserved 844-Meltlab Fast - Accurate - Complete

2 Measures temperature plateau s, exothermic reheating, and peaks for major arrests of liquidus, eutectic, and solidus. Measures smaller inflection points for oxides, carbides, gas, shrink, and some other phases. Measures curve roughness for graphite forms. Looks at speeds of solidification for nodule count Integrates areas to see shrink tendency.

3 Base Iron Chemistry Final Ductile Iron Microstructure Final Grey Iron Microstructure Aluminum Microstructure Steel Liquidus & Solidus High Alloy Steel Carbides Copper Alloy Chemistries (Phos & Silicon) Special alloys such as Molybdnum Carbide

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6 Maximum Temperature going above 2540 risks melting the thermal couple in ElectroNite 200 and 400 series cups. Liquidus Temperature caused by austenite dendrites forming and determines the Carbon Equalivant value. Eutectic Temperature caused by iron + carbon (eutectic material) forming. Combined with liquidus calculates the Carbon value. Solidus temperature at which grain boundaries freeze. Effects Austempering.

7 Carbon Equalivant from the phase diagram. Silicon and other alloys make the iron appear equalivant to this carbon. Carbon this was developed by GIRI (now ICRI) and confirmed by BCIRI. Compares favorably with combustion analysis. Better than Spectrometer analysis. Silicon rough calculation to be corrected by the spectrometer, but can be used when Spectrometer is down.

8 C.E. is calculated directly from the liquidus. Spectrometers can only guess what the liquidus might be based on imperfect equations. Some other TA units misread the liquidus by several degrees by not using derivatives. Other TA units take the Liquidus undercooling temperature instead of the growth temperature. If in doubt check the temperature calibration, and the cups those are the only things that could cause error.

9 In the range of 3% Plus, spectrometers have two issues: formation of graphite in their samples, and graphite in their standards. NIST has a standard of no more than 0.1% graphite in their 3%+ standards (caused by a mild temper). This is more than enough to through a good spectrometer off.

10 LECO warrants their instruments to be within 1% of concentration. For an Iron of 3.50% Carbon that is +/ Carbon. That is on par with the MeltLab s results when the LECO is properly calibrated. Combustion carbon standards should be shaken before used, or the fines will settle and throw off the calibration. MeltLab Carbon analysis is faster and cheaper than combustion analysis.

11 CE = C + (k 1 * Si) + k 2 Solving for SI = (CE C k 2 )/k 1 But actually CE = C +k 1 Si + k 2 MN + k 3 P k 4 Cr ASM Cast Metals (Doro Stephenescu) So 0.10 Manganese will cause a 0.06 change in the calculated silicon. Resolution: use different silicon equations for different irons where manganese or chrome change a lot.

12 Select Chemistry Correction from Toolbar When you then click on Save the analysis will change from 1.90% silicon to 1.93% silicon, but the carbon and C.E. will remain the same. The chemistry correction box will then disappear and all chemistries of that metal grade will then have the same correction. Before and After

13 Two types of cups for iron: those with and those without tellurium. With tellurium are for chemistry. Without tellurium are for microstructure. Cup wire is +/- 2 degrees F (Special Limits). Standard wire is +/-5 degrees F. Wire can melt. Glass tube can crack. Tellurium can boil too much and cause under filled cup.

14 It is possible to get irons that have a eutectic temperature higher than the liquidus. This often happens above 4.6% C.E. using Tellurium cups. C.E Liquidus 2061 Eutectic 2045

15 Each derivative increases the magnification of variations in temperature showing smaller and smaller precipitants. The rate of cooling (1 st derivative inverted) is used to find the strongest point in an arrest. This temperature is used in chemistry calculations. Second derivative shows minor arrests and shrinkage activity. Third, fourth and fifth derivatives are used to find the start and stop of a phase for integration purposes.

16 In this case, the liquidus rate of cooling was lowered to 0.2 degrees F per second by the production of austenite energy (heat). The second derivative nails when and at what temperature this occurs.

17 Base iron often contains dissolved oxygen that comes out as the iron cools. In Gray Iron, calcium is often added to the inoculant to remove the oxygen. In Ductile Iron, it just uses up some of the magnesium addition.

18 Below we show some carbides from a pipe shop. Green is the rate of cooling. Blue is the 2 nd derivative.

19 End of Eutectic in good metal. Almost good metal. Consolidated Shrinkage Micro-shrinkage

20 Control degree of smoothing Show Derivatives 2 nd 5 th Font size and Color Multiple stations on screen 1-9 stations Zoom in on arrests Select Arrests and variables to display Paste curves to Word, paste temperatures and derivatives to Excel.

21 High and low ranges for all tests. Real-time data export to text, CSV, or Excel. Additions calculation part of real-time analysis. Recall the last 100 curves from each station. And archive up to 2,000 curves per year for permanent recall. Office version for remote display over LAN. Coming soon: Data and graphics result displays to any computer over LAN.