Metal heat exchanger tube

A metal heat exchanger tube, comprising:

• a tube wall having an outside;
• integral fins formed on the outside of the tube wall, each of the integral fins having a fin foot, fin flanks and a fin tip, the fin foot of each integral fin protruding radially from the tube wall;
• a channel having a channel base, the channel being formed between the integral fins;
• and
• additional structures arranged in the channel in spaced-apart relation and dividing the channel into segments, the additional structures reducing a throughflow cross-sectional area of the channel between the integral fins locally to at least limit a fluid flow in the channel during operation, first ones of the additional structures comprising radially outwardly directed projections emerging from the channel base and each of the first ones of the additional structures being delimited in a radial direction by an end surface located between the channel base and the fin tip such that the end surface defines a radial extent of the respective projection, second ones of the additional structures comprising cavities arranged radially outward at locations of the respective projections, the cavities being formed from a material of the fin flanks and the end surface of the respective projections, each of the cavities being arranged in the radial direction between one of the end surfaces and the fin tip, the cavities being formed so as to lie laterally on the fin flank and around a radial extent of the respective projections, and the cavities are open in an axial direction.