The Notch Toughness of Commercial Ship Plate

CIM Bulletin, 1959


The lack of notch ductility in structural steel in general, and in ship plate in particular, has been the object of widespread attention in the metallurgical world since the spectacular collapse of the ill-fated S.S. Schenectady in 1943. Numerous investigations have been carried out, many new tests have been developed, and a vast amount of useful data has been published, with the result that our knowledge is now far more advanced than it was at the time of this disaster. Interest has focused largely on the medium strength steels, and the various factors which cause a normally ductile steel to behave in a brittle manner in the presence of a notch and at relatively .low temperatures have been thoroughly studied. The literature available on hightensile steels, however, is less extensive and the present paper is intended to supplement this information. Notch toughness tests have been carried out, at the request of the R.C.N., on a high-tensile manganese steel in the form of commercial ship plate. One of the newer tests, the tear t est, and the Charpy V-notch impact test, were used to examine the characteristics of plate for the constru.ction of an ice-breaker. About 250 plates, mainly in the thickness range from 1 1,4 in. to 1 % in., were t ested. An analysis of the results obtained is presented, certain aspects of the tear test are discussed, and the correlation between the two types of test is studied. On the basis of information available from casualty ships, the plates, with few exceptions, were considered to be satisfactory
Keywords: brittle fracture, ductile, manganese steel, Fracture, Fractures, Shear, Shears, steel, Steels, Temperature, test, Tests