Bethlehem Steel

About: Bethlehem Steel is a based out in . It is known for research contribution in the topics: Coating & Corrosion. The organization has 1529 authors who have published 1559 publications receiving 19098 citations. The organization is also known as: Bethlehem Steel Corporation.

Effect of continuous cooling on the morphology and kinetics of pearlite

Abstract: The effect of variations in cooling rate on the morphology and kinetics of pearlite was studied and was contrasted with the isothermal and isovelocity modes of transformation. It was found that continuous cooling suppresses the pearlite transformation to a lower reaction temperature where finer nodule diameters and interlamellar spacings are produced. Growth rates in continuous cooling were in agreement with those for the isovelocity and isothermal transformations, the rate-controlling process for growth in the temperature range studied being volume diffusion in all three cases. The relationship between interlamellar spacing and undercooling was found to be SΔT = 8.02 × 104A K, regardless of the mode of transformation.

Precipitation and Recrystallization in Some Vanadium and Vanadium-Niobium Microalloyed Steels

Abstract: Static precipitation and recrystallization following hot compression of austenite and the interactions between the two processes have been studied in a set of aluminum-killed HSLA steels containing 0.1 pct carbon, [0.016 - 0.026] pct nitrogen and 0.1 or 0.2 pct vanadium. Two steels containing both vanadium (0.1 and 0.2 pct) and niobium (0.03 pct) were included for purposes of comparison. The compression and the static tests were all carried out isothermally at temperatures between 800 and 900 °C. The course of recrystallization was followed by measurements of the rate of softening and by optical metallography of specimens quenched from the test temperature after different times. Precipitation was studied by measurements of the rate of hardening, by transmission electron microscopy of thin foils, carbon and aluminum extraction replicas, and by X-ray dispersion and energy-loss spectroscopy from individual precipitates.

Effect of the Ti/N ratio on the hardenability and mechanical properties of a quenched-and-tempered C-Mn-B steel

Abstract: Ten experimental 0.18 pct C-1.2 pct Mn- 0.002 pct B steels with various Ti/N ratios were evaluated in this study. The hardenability of these steels was first determined using Jominy tests. Slab sections were then rolled to produce 12.5-mm-thick plates, and subsequently quenched and tempered for mechanical property evaluation. The volume fraction of coarse (greater than 1 µm) TiN particles was measured in all steels using quantitative metallographic techniques. Scanning transmission electron microscopy was used to investigate fine precipitates, and scanning electron microscopy was used to examine the fracture surface of Charpy specimens. The results show that a complete boron (B) hardenability effect is obtained with Ti/N ratios ≥2.9, a value slightly below the stoichiometric Ti/N ratio of 3.4. Any excess Ti, above that which combines with N, provides an additional increase in hardenability on quenching (effect of Ti in solution) and an increase in strength on tempering (Ti (C,N) precipitation). Steels with a higher (Ti)(N) product develop a higher volume fraction of coarse TiN particles during solidification. These coarse TiN particles result in reduced toughness levels of the heat-treated plates evaluated in the present study.