How can I pass a form value from one page to another and another.

Trying to pass a form value from page to page to page. On the first page have a dropdown inside a form and passes value to my next page. On that next page, I have this code:
<cfparam name="Form.SerialNumber" default="">

I have an cfinclude statement that passes that on to another page that works fine. But I also have a form on this same page that I want to pass the SerialNumber onto. So I tried this within a form:

<form name="ChartExport" id="ChartExport" action="ChartExportProcess.cfm" method="post">
        	<INPUT type="hidden" name="SerialNumber" VALUE="#Form.SerialNumber#">
        <h6>Click on "DownLoad Files" to export to excel for processing</h6>
        <p align="center">
          <input name="btnsubmit" type="submit" class="btnsubmit" value="Download Files">
        </p>
      </form>

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so on the ChartExportProcess.cfm page I tried this for a test:
<cfparam name="Form.Dodic" default="">
<cfdump var="#Form.Dodic#" >

But I just get #Form.Dodic#.

What am I doing wrong? would try session but at the moment not an option.