Will SQL Server "int" datatype reliably truncate (and not round) decimal values when they are input?
The Microsoft Docs page for the float and real data types, says this:

Values of float are truncated when they are converted to any integer type.

In addition the CAST and CONVERT (Transact-SQL) page says:

When you convert data types that differ in decimal places, SQL Server will sometimes return a truncated result value, and at other times it will return a rounded value. This table shows the behavior.


I'd prefer to get the source software modified to not return floating point data, but short of that, if the data is not used by some process that would be life-threatening, then it looks like an implicit conversion to int should be safe.
I qualified it with &quot;non-life-threatening&quot; because it's possible there is some situation where the implicit conversion does not operate the way it is documented.  Take for instance, the details presented in the &quot;Caution&quot; section of the int Docs page.