Author : J. H. Gross
Publisher :
ISBN 13 :
Total Pages : 34 pages
Book Rating : 4.:/5 (492 download)
Book Synopsis Effect of Copper on the Aging Characteristics of Cu-Ni Structural Steels by : J. H. Gross
Download or read book Effect of Copper on the Aging Characteristics of Cu-Ni Structural Steels written by J. H. Gross and published by . This book was released on 2000 with total page 34 pages. Available in PDF, EPUB and Kindle. Book excerpt: Abstract: "In previous ATLSS studies, improved fracture toughness and weldability of 80W, 90W, and 100W copper-nickel bridge/infrastructure steels were demonstrated with existing 80-, 90-, or 100-ksi (550, 620, or 690 MPa) yield strength structural weathering steels. The improvements result from the strengthening of the Cu-Ni steels by copper precipitation as well as by conventional transformation to low-temperature microconstituents. This dual-strengthening permits a significant reduction in carbon content and the resultant superior toughness and weldability of the Cu-Ni steels. In a further study of the composition of Cu-Ni steels, the effect of copper-content variation on hardenability and mechanical properties was investigated. Equally important, is the effect of copper content on the aging characteristics of this type of precipitation-strengthened steel. Therefore, the study of the effect of copper content was extended in the present study to determine the time-temperature relations on the aging characteristics of the Cu-Ni steels having copper contents in the range 0.25 to 1.20 percent. For the class of steels investigated as candidates for a 100W bridge steel, the following conclusions were drawn: 1. a copper content of about 1.0 percent was adequate to maximize precipitation strengthening, 2. the hardness due to copper precipitation strengthening exhibited the greatest increase at 950F (501C), was not altered appreciably at 1050 or 1150F (565 and 620C), but decreased progressively with time at 1250F (675C), 3. with respect to the effect of time on copper precipitation strengthening and softening of the MA constituent, the following was observed: a. at 950F (510C), strengthening occurred for four hours, b. at 1250F (675C), softening occurred progressively for eight hours, c. at 1050 and 1150F (565 and 620C), strengthening and softening essentially balanced each other over the total aging time."