INVESTIGATION OF THE EFFECTS OF FABRICATION VARIABLES ON THE CORROSION RESISTANCE OF ZIRCALOY-2
A comprehensive investigation was conducted of the effect of melting and fabrication variables on the corrosion resistance of Zircaloy-2 in 750 deg F steam at 1,500 psi. Two 12-in. diameter production-type ingots and three 4-in. diameter laboratory-type ingots were produced, representing primary and secondary melting in 75% helium-25% argon atmosphere, primary melting in 75% helium-25% argon and secondary melting in vacuum, and primary and secondary melting in vacuum. Variations were made in the ingot forging procedures, hot rolling temperatures, homogenization treatment, and final heat treatment of the hot rolled Zircaloy-2 strip. Corrosion data were obtained on the strip produced from the large ingots after 14, 28, 56, 70, 84, and 112-day intervals. Corrosion data were obtained on strip produced from the small ingots at 14 and 28-day intervals. The weight-gain data were statistically analyzed. The major findings include the fact that 1900 deg F heat treatment followed by a slow cool resulted in detrimental corrosion resistance, regardless of fabrication and melting technique. It was also found that secondary vacuum melting resulted in a more corrosion- resistant Zircaloy-2 strip than that produced from secondary atmosphere melted material. It was found that there was no advantage in a primary inert atmosphere and secondary vacuum melt over a double vacuum melt. It appeared that minimizing reheat and/or conditioning operations during forging was beneficial to the corrosion resistance. Rolling temperature in the range of 1430 to 1675 deg F and homogenization treatment seemed to have little significant effect from a practical standpoint on the corrosion resistanice of Zircaloy-2. It was found, however, that Zircaloy-2 corrosion in 750 deg F steam is statistically significantly affected by almost any change in fabrication variables. Most of these factors, except those outlined, however, appear to be too small to be of practical significance. (auth)
- Research Organization:
- United Nuclear Corp., New Haven, Conn.
- NSA Number:
- NSA-16-025726
- OSTI ID:
- 4803355
- Journal Information:
- Trans. Am. Soc. Metals, Journal Name: Trans. Am. Soc. Metals Vol. Vol: 54
- Country of Publication:
- Country unknown/Code not available
- Language:
- English
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