TWI Industrial Member Report Summary 833/2005
By D J Abson
Background
An important part of the drive to achieve higher thermal efficiency in thermal power plant is the move towards progressively higher operating temperatures. Such an aim requires the development of alloy steels with adequate ambient temperature properties, and with improved creep rupture strength at operating temperatures in excess of 600°C.
The present report is part of a programme in which weld metals of different composition, based on modified 9 to 11%Cr steels, suitable for welding 92 grade steels, are being investigated. Previous reports [1,2] have examined the consequences for toughness and creep rupture strength of changes in the levels of cobalt, nickel and Cr on modified 9%Cr manual metal arc (MMA) weld metal. Flux-cored wires are being used increasingly, to achieve higher productivity, the deposits generally contain higher levels of Ti and Al than those in MMA welds. The present report therefore examines the consequence of making minor changes to the levels of Ti and Al on the mechanical properties of cored wire weld metal.
Objective
- To determine the influence of Ti and Al contents on the toughness and creep rupture strength of 92 grade flux-cored weld deposits for 9%Cr steels.