Fig. 16 shows quick-fit connec-tions for joining hoses for liquidand gaseous media which used tobe manufactured from corrosion-resistant steels. By using the QPQ®salt bath nitrocarburizing process itwas possible to change from theexpensive base material to anunalloyed case hardening steel. Inthe QPQ® treated condition therequired corrosion and wear resis-tance is achieved without anyproblems.