Effect of microstructure and alloying elements on the resistance of fastener grade steels to hydrogen assisted cracking

Fastener grade steels with varying alloy contents and heat treatments were employed to measure changes in resistance to hydrogen assisted cracking. The testing procedure compared notched tension specimens fractured in air to threshold stress values obtained during hydrogen charging, utilizing a rising step load procedure. Bainitic structures improved resistance by 10-20% compared to tempered martensite structures. Dual phase steels with a tempered martensite matrix and 20% ferrite were more susceptible and notch sensitive. High strength, fully pearlitic structures showed an improvement in resistance. Carbon content, per se, had no effect on the resistance of steel to hydrogen assisted cracking. Chromium caused a deleterious effect but all other alloying elements studied did not cause much change in hydrogen assisted cracking susceptibility.

ANALYSIS OF GENDER RELATIONS IN THE INDUSTRIAL COMMUNITY OF AGUIRRE, PUERTO RICO

This thesis is a study of the gender relations of the residents of Aguirre, Puerto Rico, between 1940 and 1991. The primary goal of the project was to explore how gender roles and relations in the Aguirre community were impacted by the social class system introduced by the Aguirre Sugar Company. This project was based on the interpretation of the past and present situation of the Aguirre community using oral history, by conducting a series of interviews among its residents. The interviews resulted in three main themes. First, the concepts of `normal and natural' were used to distinguish gender roles. Second, Aguirreños identified `family as community', since through the family individuals built their gender identity and learned the basic rules of coexistence within the social hierarchy of the community. Third, although the gender and class roles were clear in the community, `resistance and negotiation' occurred in the home and at the Company between those of different gender and social classes. The Aguirre Sugar Company was one of the principal influences on the construction of the Aguirreños identity, and left a mark on the past, present and future generations.