The in-form side had already guaranteed top spot in Group A and a berth in the quarter-finals, but their record of five wins from five matches sends a strong message to their rivals.
Kazakhstan were playing for pride, as their last defeat - against Italy - sealed their fate.
Croatia took the lead within 30 seconds of the start from a man-up goal and kicked on to take the period 4-0.
The Kazakhs fared better in the second quarter as they shared the spoils with their opponents with one goal apiece.
Croatia stepped up a gear in the third period to forge a six-goal lead and take the score to 9-3 at the whistle.
They increased their advantage further in the final period to score three more goals before Kazakhstan netted from distance to make the final score 12-4.