Mfr. of martensitic chromium steel workpiece - by controlled, cyclic heat-treatment schedule to give improved mechanical properties

摘要

Mfr. of a semi-finished pt. or workpiece from single-phase martensitic 9 to 12% Cr steel, comprising: 1) subjecting a blank to a sequence of cold working and soft annealing steps, wherein 2) a stabilising anneal is performed, above the A2Cl temp. but below the austenising temp., after cold working of about 20% and before soft annealing; 3) hard annealing is performed for 1 hr max. in the austenising region at 950-1100 deg.C, followed by final treatment stages, which are possibly repeated cyclically, comprising: 4) heating the pretreated blank to 100-450 deg.C; 5) further working if necessary; 6) a tempering anneal at 600-800 deg.C, where the hard annealing and final treatment are performed at least long enough so that deformation working has to be effected with a degree of working of 80% to give the semi-finished pt. or workpiece. ADVANTAGE - An improvement in the mechanical properties of martensitic Cr steels, esp. their ductility and resistance to softening due to radiation, fatigue and cree