THE EFFECT OF METALLURGICAL VARIABLES IN SHIP-PLATE STEELS ON THE TRANSITION TEMPERATURES IN THE DROP-WEIGHT AND CHARPY V-NOTCH TESTS

摘要

Twenty-nine heats were produced and processed in the laboratory in order to study the effects of composition and ferrite grain size on drop-weight transition temperatures. To provide an internal check and to permit comparisons with other investigations, parallel studies were made on V-Notch Charpy specimens. The experimental steels covered the following ranges in composi¬tion: 0.10/0.32 % carbon, 0. 30/1.31 % manganese, 0. 02/0.43 % silicon and nil/0.136 % acid soluble aluminum. These ranges were intentionally wider than the limits permitted for ship plate. Although most of the data were obtained on hot-rolled samples, some plates were heat-treated in order to cover a wider range in ferrite grain size.nThe experimental data were used for a multiple correlation analysis conducted with the aid of an electronic computer. The study showed that car¬bon raises and manganese, silicon, aluminum and finer ferrite grain sizes lower both drop-weight and Charpy transition temperatures. Quantitatively, variations in composition and grain size have a more marked effect on V15 Charpy transition temperatures than on the drop-weight transition temperature.nUseful correlations were found between transition temperatures in drop-weight tests and those defined by seven different criteria for Charpy tests.nEvidence was accumulated that conditions ordinarily used for drop-weight tests are more severe for 1-1/4-in. thick plate than for 5/8-to 1-in. thick plate.