Rosenhain Centenary Conference - 2. Design implications for materials selection 2.2 Design against brittle fracture

Abstract

The paper assesses the current position and future trends in a complete definition of the problem of brittle fracture. It is concluded that there is a need for a more uniform approach to the specification of toughness requirements in present design standards, and ways of achieving this are indicated. The acceptance of the presence of defects leads to the use of fracture mechanics techniques in defining conditions for avoiding fracture initiation. A new treatment for a toe crack in a fillet weld is illustrated, as an example of this approach. Because of interpretation and experimental difficulties in assessing the fracture toughness of weld metals and heat affected zones, it is concluded that it would be inappropriate to use the c.o.d. test, on its own, to specify material toughness levels for National Standards. Some of these difficulties are illustrated and areas for future research are discussed, including the role of the physical metallurgist.