A heat exchanger tube in a heat exchanger for an ice making machine includes a bimetallic heat exchanger tube to improve capacity and wear characteristics of the heat exchanger. The heat exchanger tube has an outer portion with a first material composition and an inner portion with a second material composition where the first material composition is different from the second material composition. The first material composition is compatible with the refrigerants used in the heat exchanger unit of the ice making machine. The second material composition is compatible with the feed solution being chilled in the heat exchanger tube.