This is what I found on Delta's website:
You can check two bags per passenger free of charge.
Each bag must:
Weigh 50 pounds (22.5 kg) or less.
Not exceed 62 inches when you total length plus width plus height.
If you have a bag that exceeds these allowances, see Excess Baggage.
Exceptions:
Passengers traveling to or from Key West and Marathon, Florida are limited to only one checked bag.
The free weight allowance is 70 pounds (32 kg) for tickets purchased in Brazil.
With the exception of original factory-sealed boxes that will be accepted on a standby basis, we do not accept boxes as checked baggage to Central or South America (except Brazil, Mexico, and Chile) at any time of the year.