Factors That Determine the Applicability of High Strength Quenched and Tempered Steels to Submarine Hull Construction
Abstract
An analysis is given of the potentials and limitations of high strength, quenched and tempered (Q and T) steels for welded construction of submarine hulls. The experience that has been developed in the use of such steels in a wide variety of applications provides the essential background for preassessment of fabricability and design problems in hull construction, as a function of increasing strength level. With increasing strength level, there is a decrease in fracture toughness level which requires an upgrading of fabrication and design quality levels for purposes of maximizing structural reliability. The explosion tear test and the drop-weight tear test and new methods designed for the evaluation of the fracture toughness of plate materials and welds. The explosion tear test is used to estimate the flaw size-fracture stress relationships. Correlations of these data with drop-weight tear test data and Charpy V test data provide an indirect assessment of these relationships. These tests cover an extensive range of materials and strength levels. Collective consideration of these factors lead to the conclusion that Q and T steel hull fabrication capability at the 120-130 ksi yield strength level may be attained by a short term development program. The attainment of similar capabilities at the 150 ksi yield strength level is a ceiling aim requiring research solutions relating to weld metals, prior to entering a development stage. The attainment of a practical fabrication capability at yield strength levels in excess of 150 ksi is not feasible. The best promise of hull steels with strength levels in excess of 150 ksi is in the development of an entirely new family of materials based on new metallurgical concepts of hardening.
Document Details
- Document Type
- Technical Report
- Publication Date
- Dec 05, 1962
- Accession Number
- AD0298117
Entities
People
- P. P. Puzak
- W. S. Pellini
Organizations
- United States Naval Research Laboratory