as 4 in square ingots the ingots were forged to 2 u00bc in square bars from a starting temperature of about 2100 u00b0 f the bars were cut to shorter lengths and half of the shorter length bars were further forged to 1 in square bars again from a starting temperature of 2100 u00b0 f the 1 in bars were cut to still shorter lengths which were forged to u00be in square bars from 2100 u00b0 f the u00be in square bars and the remainder of the 2 u00bc in square bars were annealed at 1050 u00b0 f for 6 hours and then cooled in air to room temperature standard specimens for tensile testing and standard specimens for charpy v notch impact testing were prepared from the u00be in bars of each heat standard compact tension blocks for fracture toughness testing were prepared from the 2 u00bd in square bars of each heat all of the specimens were heat treated at 1585 u00b0 f for 30 minutes and then air cooled the test specimens were then chilled at u2212 100 u00b0 f for 1 hour and warmed in air to room temperature duplicate specimens of each heat were then tempered at one of three different temperatures 400 u00b0 f 500 u00b0 f and 600 u00b0 f by holding at the respective temperature for 3 hours the tempered specimens were then air cooled to room temperature the results of mechanical charpy v notch and fracture toughness testing on the tempered specimens are presented in table ii below including the 0 2 offset yield strength y.