Autodesk Inventor has the support for IGES/IGS format so it should be pretty easy to convert IAM to IGES using that. You can also probably find some dedicated CAD converters that will help you with this conversion.
Convert Autodesk Inventor assembly file to IGES 3D exchange format.
We found 7 software records in the database related to .iam to .igs file format conversion.
Microsoft Windows software - convert iam to igs on Windows
A CAD converter with huge format support
Convert from iam file format
The tables with software actions are a good pointer for what a certain program does with various file types and often may give users a good hint how to perform certain file conversion, for example the above-mentioned iam to igs. However, it is not perfect and sometimes can show results which are not really usable because of how certain programs work with files and the possible conversion is thus actually not possible at all.
A widely-used 3D animation application from Autodesk
A 3D CAD translation softwate
A dedicated CAD converter
Autodesk Inventor is modeling application used to create 3D digital prototypes.
A CAD visualizaton, analyzation and translating system
A CAD viewer program with conversion capabilities