This article presents the results of investigations on HR6W alloy and Sanicro 25 steel and the dissimilar welded joint made of them. The characteristic images of microstructure of the investigated materials in the as-received condition and following the creep test, observed with a scanning electron microscope (SEM), are shown. The X-ray analysis of phase composition of the existing precipitates was carried out. The method for evaluation of creep strength based on abridged creep tests carried out at a temperature higher than the design one is presented. The obtained results do not deviate from the values of creep strength determined in longterm creep tests. The maximum difference in creep strength of the investigated materials is ±20%, which is in compliance with the acceptable scatter band. The methodology presented can be used for verification of creep strength (life time) of the material of finished components to be operated under creep conditions.

This paper presents the evaluation of durability for the material of repair welded joints made from (13HMF) 14MoV6-3 steel after long-term service, and from material in the as-received condition and after long-term service. Microstructure examinations using a scanning electron microscope, hardness measurements and creep tests of the basic material and welded joints of these steels were carried out. These tests enabled the time of further safe service of the examined repair welded joints to be determined in relation to the residual life of the materials. The evaluation of residual life and disposable life, and thus the estimation and determination of the time of safe service, is of great importance for the operation of components beyond the design service life. The obtained test results are part of the materials' characteristics developed by the Institute for Ferrous Metallurgy for steels and welded joints made from these steels to work under creep conditions.

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RESIDUAL LIFE OF BOILER PRESSURE PARTS MADE OF THE 13CrMo4-5 STEEL AFTER LONG-TERM OPERATION IN A CREEP CONDITIONSThis paper presents the method for determination of the time of further safe service for welded joints of boiler components after exceeding the design work time. The evaluation of the life of the parent material and its welded joints was performed. Microstructure investigations using a scanning electron microscope, investigations of strength properties, impact testing, hardness measurements and abridged creep tests of the basic material and welded joints were carried out. The investigations described in this paper allowed the time of further safe service of the examined components made of 13CrMo4-5 steel to be determined. The method for determination of the time of safe service of boiler components working under creep conditions allows their operation beyond the design service life. The obtained results of investigations are part of the materials database developed by the Institute for Ferrous Metallurgy.