leometwu的部落格

1. Be sure to test the iron melt before inoculation treatment. If you sample the inoculated iron melt of  high CE value, you probably will not get a flat curve on the TE area.  TE is used to calculate Si% and Si% is only correct if TE curve is flat.  FC is calculated from CE, which, in turns, is calculated from TL, the first thermal arrest on the cooling curve. FC (CE) is always correct even if you get a wrong TE curve, that is to say that FC is dependent on TL only and is independent of TE.

2. Give good protection to the wiring of cup stand. Do not splash iron melt onto the wiring to prevent a short-circuiting of the "Thermocouple Circuit".  CE_Meter will remind you to remove a cup after a testing is done. Removing the cup will get you a message of  " Open circuit....." If nothing happens on the screen after removing a cup from the cup connector, you are in trouble-------there is a short circuiting between cup stand and the computer.  Usually, two conductors  ( + and - wires) are now in contact with each other inside the yellow outer jacket. Right now, all you have to do is peel the outer jacket and seperate the "fused" area if it is still easy to seperate. If it is difficult to seperate them, just cut off the fused length and re-wire them together.  Twist wire to re-connect wire, do not use soldering.

3. Pour the sample melt at a proper temperature.  Too high  a pouring temp will burn the sensor wire in the cup and no temp signals will be sent to computer.  Too low  a pouring temp will lead to an " up-hill" at TE area on the cooling curve and lead to an "No Good!" message*. *Note: N.G. for Si% and C% results. But the CE and FC obtained from TL is still good because TE is independant of TL.

4. FC number dispalyed.   FC number dispalyed, say FC 250,  is for the plate of 2o  mm thickness, or, test bar poured with a diameter of 30 mm and machined to size, with its iron melt inoculated and unalloyed .  Pouring iron melt of FC 250 to thicker plate will have strength and hardness lower than FC 250.  Pouring iron melt of FC 250 to thinner plate will have strength and hardness higher than FC 250.

CE_Computer Instruction Manual:

◆ System Configuration

 Set targets You can set any number of targets, using mouse to click a button on the screen. Then key-in material name and press [Enter]..

     Pointing mouse arrow at the cell to be keyed-in, and press the select button of your mouse. Then you can key in numbers with number keys on your keyboard.

◆ C% Si% offset  C% & Si% displayed on monitor can be modified to get closer to the results obtained from spectrometer. Note that “displayed value = calculated value + offset value”. If displayed value is higher than spectrometer value, add a “-“ sign in front of the offset number.   

 Note: each iron should have its own offset value.

      Re-check: After putting-in an offset value, you can now recall a curve to see NEW values of Si% or C% and see if you are doing it in the right direction.

  Melt Load    Key-in 1000 Kg for a one tone furnace.

  Print Select : Auto-Print will print out after each pouring of the CE cup; You can print Curve+Data, or Data only.

  Temp. Rectifying: Upper left cell: Add a number to rectify temperature deviation from cup. The temp. sensor wire in the cup is produced by alloy melting and then made to wires. Accuracy of temperature varies from heat to heat. The tolerance for “precision grade” is +/- 4C . 1C lower in temp, you will have 0.05% higher in Si. That means, if wire sensor in this batch is from a different heat. Then you have to put their differences in temperature accuracy into account. If you have – 3C in your last batch of cups, and + 3C for your new cups. Then you have to put – 6C in this cell to get the same readings of C%, Si% for the same melt poured. If you do not rectify this, Si% reading of new cup for the same melt will be lower by the amount of 0.05% x 6 = 0.3%. 

◆    ◆C, Si measurement  Pour iron melt from sampling scoop to CE cup. Watch out for melt temp. in cup. Too high a temp. it will burn the sensor wire in cup. Too low a temp. it will not obtain a “flat” TE plateau of the cooling curve. A Tmax in cup between 1250~1300 is most desirable. Pour the melt onto the inner wall of cup instead of onto glass tube directly. Fill the cup fast at beginning and dwindle down until cup is full. Filling speed should be such that glue in cup evaporate when cup is half full. At this stage, stream of melt should not be interrupted until cup is 90% or 100% full.  Too fast of the filling speed, melt will spill out of the cup. Too slow, melt will not absorb enough Tellurium in the cup. Te is used to have the melt solidify “white” in order to obtain correct Si% calculation.

◆     

◆    ◆ Curve Review  

Curves will be save automatically to the directory or file 00000001 up to 80 curves. Then, if will automatically create file 00000002 to save No. 81 and so on. To see history curve, click the curve of interest and then select “open”. At this mode, click the LEO icon on the bottom left and you will have a slow-motion curve review.

◆ Trends of C, Si  Each test result of CE, C, Si  will be plotted on curve to show its trend. To print it out every day for documentation.

◆ Info ?  This contains instruction manual you are reading and can hold some metallurgy-related information obtained from book.

◆ Exit   .Select  9 “Win_ 98”

 The manufacturing tolerance of sensor wire in cup is +/- 4 C for precision grade. Watch out for this when new cups arrive. Pour a new cup and an old cup for comparision and rectify the difference in you computer.:

*Temp lower by 1 C   --->  C (or CE) increases 0.01 %   but Si will increase by the amount of 0.05%       

*Temp 5C lower   --->  FC will be 10 lower,  for example 260 to 250,

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. Notes on using CE_Computer:

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    0.  Te in cup is aiming at a “white” eutectic freezing of the melt in the cup. Sampling scoop should not brushed with graphite because graphite help “gray” eutectic freezing and as a result, you do not obtain a Si% reading.

    1.  Pour the cup >90% full each time..

    2. Avoid direct blowing of fan to cup during testing

    3. Tmax in cup should be between 1250 C ~ 1300 C . Too low, Tellurium will not be absorbed into the melt and it will freeze “grey” and “No Good”. Too high, sensor wire will be burnt. Melting point of sensor wire is only 1350 C .                      

    4. The frozen lumps of sampling iron can be returned to furnace little by little, say 1 or 2 at a time. Do not put too many of them into furnace at one time because the strong white tendency of the Te.

    5.  The influence of each 1% of element on eutectic freezing temp (TE).

                     Cu:  - 2.       +  means “increase”

                     Ni:   - 6

                     Cr:  + 7

                     Mn:  + 3

                     P :   -38        -  means “decrease”

                         Si :   - 20

  CE_Computer bases on the assumption that “only C and Si are present in the iron melt” and calculates Si% without the influence of other elements. If P is present in the melt. Because P has an even greater influence on TE, The computer will not be able to give a correct Si% reading. But CE and FC reading will still be correct.  That is to say, CE and FC is depending of TL temp and is independent of TL temperature.