Тепловая хрупкость стали 175-мм пушечных труб. Technical Report AMMRC TR 69-16, Army materials and mechanics research center. 1969. – 18 p.Sections of two 175-mm M113 gun tubes were utilized to study the development of both reversible and irreversible temper brittleness in 3 percent nickel-chromium gun steel. Relative material toughness indicated by the 100 percent fibrous transition temperature was determined on numerous groups of specimens tempered between 900 and 1200 F for various times.
A tempering range of 1075 to 1100 F produced optimum toughness at the required 160 to 180 ksi yield strength for tempering times consistent with the section size of forgings for 175-mm tubes» Lower tempering temperatures resulted in a greater degree of reversible temper brittleness, particularly 1000 F, which produced maximum embrittlement within the limits studied. Regression was observed at 1050 F after prolonged tempering.
Both the kinetics of temper brittleness and the effects of composition on the degree of embrittlement are discussed in terms of numerous determinations available in the literature. The indirect effect of temperability as well as the dual role of some elements such as molybdenum and vanadium are described. Previous limited results from a cursory study performed by a producer are explained in terms of embrittlement and regression.Contents:
Abstract.
Introduction.
Procedure.
Results and discussion.
Irreversible temper brittleness.
Toughness and tempering temperature.
Temperability and reversible temper brittleness.
Anisothermal embrittlement.
Temper brittleness.
Composition and toughness.
Quality assurance.
Summary.
Literature cited.
