Current Tests For Evaluating Fracture Toughness Of Sheet Metals At High Strength Levels

Current Tests for Evaluating Fracture Toughness of Sheet Metals at High Strength Levels

Current Methods of Fracture-toughness Testing of High-strength Alloys with Emphasis on Plane Strain

Fracture-toughness testing using principles of fracture mechanics has developed to the point where it can be used as a basis for selection of materials, for estimating limiting design stresses assuming the presence of small flaws, and for analyzing failures. Current methods of measuring plane-stress and plane-strain fracturetoughness parameters are presented in this report. The specimens include center-cracked, edge-cracked, single-edge-cracked, surface-cracked, and notched round bars, which are subjected to tensile loading, and notched bars for bend tests. The different types of specimens permit evaluating sheet, plate, bar stock, and forgings as well as material from failed structures. Application of fracture-toughness parameters to design of high-strength structures is reviewed for both static and fatigue loading. Consideration of the fracture-mechanics concepts in design should lead to fewer problems with brittle fracture in high-strength structures. (Author).

Cracking in High-strength Steel Weldments

Weldment cracking is a broad complex field. Even if one considers only cracking of steel weldments, the problems range from cracking at temperatures near the solidus during welding to cracking at room temperature days, weeks, or months after welding is completed. Numerous reports of investigations in this field are contained in the published and unpublished literature. However, most of these reports cover only a particular problem in a specific area of the broad field of weldment cracking. This review attempts to cover the major aspects of the entire field of weldment cracking. Necessarily, the review is for the most part general, only being specific in a few instances to illustrate a point. (Author).