how to make Grid unsortable

I have a requrement to show the data in some Grids in a certain sort order, but the sort order of the Grid should not be changeable by clicking in the Grid headers.

Is this somehow possible?

With table, i could just call setSortEnabled(), which is not present in Grid.

You need to apply Grid.Column.setSortable(false) for all of your Grid columns. There is also Grid.getColumns() method which gives you list of Grid.Columns, which makes it easier to do this for all columns, if you have really many.
 

Ok, on those Grids, i have a maximum number of 4 columns, so that solution should be fine.