Full Description

With the increasing use of thick-section quenched and tempered steels for nuclear and chemical reactors, there is a definite need for information on the properties of some of the newer low-alloy high-strength steels when given such thick-section heat treatment. Of particular interest are yield and tensile strengths attainable, the notch toughness to be expected, the plastic fatigue strengths available and the kinds of microstructure that appear to be characteristic of these thicknesses.

In the program reported here, four quenched and tempered heavy-section steels-A212 Grade B, A533 Grade B, A542 and A543 - were studied in the simulated 6-in. thick and 12-in. thick quenched, tempered and stress-relieved condition. Specimens taken from these simulated heavy sections were evaluated to provide a characterization of the properties and structure of heavy-section, heat-treated, low-alloy steels.

The results show that increasing the section size from 6 to 12 in. produced no important changes in strength, notch toughness or fatigue resistance in these steels in the quenched, tempered and stress-relieved condition. When comparing 1-in. thick plate with the heavy sections, strength decreased only modestly while notch toughness decreased substantially. Because of their initial good toughness, however, the alloy steels still exhibited transition temperatures below -10F. The fatigue and elevated temperature properties of the steels were similar to those found in thinner sections of equivalent tensile strength. The results of the microstructure study confirmed the mechanical property tests in that little difference in microstructure was observed between the 6-in. and 12-in. conditions.

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Published: 1967 Number of Pages: 34 File Size: 1 file , 7.7 MB