Strangeness from 20 A GeV to 158 A GeV

New results from the energy scan programme of NA49, in particular kaon production at 30 A GeV and Φ production at 40 and 80 A GeV are presented. The K + /π + ratio shows a pronounced maximum at 30 A GeV; the kaon slope parameters are constant at SPS energies. Both findings support the scenario of a phase transition at about 30 A GeV beam energy. The Φ/π ratio increases smoothly with beam energy, showing an energy dependence similar to K - /π - . The measured particle yields can be reproduced by a hadron gas model, with chemical freeze-out parameters on a smooth curve in the T-μ B plane. The transverse spectra can be understood as resulting from a rapidly expanding, locally equilibrated source. No evidence for an earlier kinetic decoupling of heavy hyperons is found.