Mechanical Properties of Hot-rolled Plates of Large Size for Plant Engineering.

Large-size plates of commercially pure titanum of grades 1, 2 and 3 according to DIN 3. 7025, 3. 7035 and 3. 7055 up to 3500 mm width and a maximum length of 10,000 mm with a thickness of 7 and 30 mm have been tested. They fulfill the acceptance specifications for hot-rolled plates of conventional size regarding flatness, thickness tolerances and mechanical properties at room temperature. Additional investigations between minus 196 degree C and plus 400 degree C on the mechanical properties and notched impact strength of plates and weldments, as well as their fatigue stength at room temperature show, independently of the rolling direction, the possible influence of grain size and interstitials like oxygen and hydrogen as well as the iron content on the properties. The notched impact strength has a maximum at 100 degree C without a steep drop at lower temperatures. The decrease in tensile strength and proof stress with increasing temperature shows a retarding effect at 150 degree C. The elongation reaches a maximum at 200 degree C, combined with a low ratio of yield strength to tensile strength.