The tensile deformation and fracture characteristics of two ship plate steels and one low-alloy steel were determined from 25 C (77 F) to -196 C (-321 F). Both smooth and notched specimens were used and the true stress-natural strain data conform to the relation ?=???? in the strain interval 0.075 < ? < 0.30. The strength coefficient ?? was to increase regularly with decreasing temperature, whereas the strain hardening exponent ? of the ship steels dropped to a relatively low value at low temperature.