High temperature behaviour of P91-steel weldments Paper

The present paper reports on a study on the deformation and creep crack growth (CCG) behaviour of somewhat brittle high strength martensitic steel Grade P91 steel weldments at 600 C. The weld joints were produced with a spectrum of industrially relevant weldment properties. It included materials with weld metal resistance to creep deformation and crack growth was (a) lower, produced by butt welding (BW), and (b) higher, produced by electron beam welding (EBW). Therefore, the materials studied cover a spectrum of microstructures and ductility to give representative data that applies to a range of weld types. The high temperature properties were determined on standard round tensile and creep specimens. Crack growth was studied using C(T)25 (W=25mm, B=12.5mm) and C(T)50 (W=50mm, B=15mm) type specimens, under constant load that produced CCG data in the small-scale creep to extensive creep ranges. The starter cracks were spark eroded due to the difficulty of producing fatigue pre-cracks located in the narrow weld and HAZ regions. The emphasis is placed on the crack growth initiation and applicability of test procedures and the crack tip parameters that will lead to provision of guidelines for industrial weldment crack growth assessment and analysis. (orig.)Available from TIB Hannover: RA 3251(2001/34) / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekSIGLEDEGerman