Abstract: A high temperature refractory brick wall is repaired by removing and replacing damaged brick while the wall is maintained at a temperature below normal operating temperature but sufficiently high to avoid damage from contraction resulting from cooling. New brick having a coefficient of thermal expansion compatible with the heated wall are used to avoid cracking of the wall due to expansion during heat-up. Workers wearing protective clothing, preferably incorporating a circulating fluid cooling system, remove the damaged brick and install new brick in their place in walls having surface temperatures of about 500.degree. F. or higher and internal temperatures substantially above 500.degree. F., preferably at least about 1500.degree. F.

Abstract: Steel well casing having the combined properties of excellent resistance to hydrogen sulfide stress corrosion and high yield strength ranging upward from 90,000 to 145,000 psi comprised of an aluminum-killed steel alloyed with chromium, molybdenum and vanadium. The casing is quenched to martensite from an austenitizing temperature in the range of from 1550.degree. to 1700.degree. F. and is tempered in the range of from 1200.degree. to 1400.degree. F. to a maximum hardness of 35 R.sub.C.