Cleavage fracture in high strength low alloy weld metal
- Univ. of Birmingham, Edgbaston (United Kingdom)
The present investigation gives an evaluation of the effect of microstructure on the cleavage fracture process of High Strength Low Alloy (HSLA) multipass weld metals. With additions of alloying elements, such as Ti, Ni, Mo and Cr, the microstructure of C-Mn weld metal changes from the classical composition, i.e., allotriomorphic ferrite with acicular ferrite and Widmanstaetten ferrite, to bainite and low carbon martensite. Although the physical metallurgy of some HSLA weld metals has been studied before, more work is necessary to correlate the effect of the microstructure on the fracture behavior of such weld metals. In this work detailed microstructural analysis was carried out using optical and electron (SEM and TEM) microscopy. Single edge notched (SEN) bend testpieces were used to assess the cleavage fracture stress, {sigma}{sub F}. Inclusions beneath the notch surface were identified as the crack initiators of unstable cleavage fracture. From the size of such inclusions and the value of tensile stress predicted at the initiation site, the effective surface energy for cleavage was calculated using a modified Griffth energy balance for a penny shape crack. The results suggest that even though inclusions initiate cleavage fracture, the local microstructure may play an important role in the fracture process of these weld metals. The implications of these observations for a quantitative theory of the cleavage fracture of ferritic steels is discussed.
- OSTI ID:
- 442990
- Report Number(s):
- CONF-950682-; ISBN 0-87170-567-2; TRN: IM9712%%415
- Resource Relation:
- Conference: 4. international conference on trends in welding research, Gatlinburg, TN (United States), 5-9 Jun 1995; Other Information: PBD: 1996; Related Information: Is Part Of Trends in welding research: Proceedings of the 4. international conference; Smartt, H.B.; Johnson, J.A. [eds.] [Idaho National Engineering Lab., Idaho Falls, ID (United States)]; David, S.A. [ed.] [Oak Ridge National Lab., TN (United States)]; PB: 836 p.
- Country of Publication:
- United States
- Language:
- English
Similar Records
Modeling macro-and microstructures of gas-metal-arc welded HSLA-100 steel
Austenite decomposition during continuous cooling of an HSLA-80 plate steel