A STUDY OF EFFECTS OF HEAT TREATMENT AND HOT-COLD-WORK ON PROPERTIES OF LOW-CARBON N-155 ALLOY

摘要

Physical properties at room temperature and rupture teat characteristics at 1200℉ were used as criterions to evaluate the effects of systematic variations of solution treatments, aging treatments, and hot—cold-work on the properties of bar stock from one heat of low-carbon N-155 alloy. The range in yield strength for 0.02—percent offset at room temperature was from 30,000 to 134,000 psi. Rupture strengths at 1200℉ ranged from 40,000 to 66,000 psi at 100 hours and from 35,000 to 56,000 psi at 1000 hours. This rupture-strength range is equivalent to such extreme variation as 100 to approximately 600,000 hours for fracture at 1200℉ under a stress of 40,000 psi for the same bar stock with different treatments.nHot—cold-work in amount of 10— to 15—percent reduction at temperatures below l400℉ produced the highest strengths at both room temperature and 1200℉. Solution temperatures prior to hot—cold-work should he between 1950° and 2100℉.