High strength weldable seamless tube of low alloy steel with niobium
OwnerRobert B. Mantoninventor
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Abstract
A high strength weldable seamless tube of low alloy steel containing 0.24 to 0.28 percent carbon, 1.30 to 1.50 percent manganese, 0.15 to 0.35 percent silicon, not more than 0.01 percent sulphur, not more than 0.03 percent phosphorous, not more than 0.20 percent copper, 0.13 to 0.20 percent chromium, 0.15 to 0.60 percent molybdenum, 0.007 to 0.05 percent of aluminum, not more than 0.02 percent nitrogen, 0.02 to 0.04 percent titanium, 0.0007 to 0.0025 percent boron, 0.02 to 0.10 percent niobium, and the balance iron. The tube is preferably heated to an austenization temperature of about 1,670.degree. F. and simultaneously internally and externally quenched by a special process that provides for high internal cooling rates followed by tempering at about 1,050.degree. F.
Claims4
A high strength weldable seamless tube which has been heated to an austentization temperature of about 1,670.degree. F. and simultaneously internally and externally quenched and containing 0.24 to 0.28% carbon, 1.30 to 1.50% manganese, 0.15 to 0.35% silicon, not more than 0.01% sulfur, not more than 0.03% phosphorus;
- not more than 0.20% copper, 0.13 to 0.20% chromium, 0.15 to 0.60% molybdenum, 0.007 to 0.05% aluminum, not more than 0.02% nitrogen, 0.02 to 0.04% titanium, 0.0007 to 0.0025% boron, 0.02 to 0.10% niobium, and the balance iron, and wherein said tube has a minimum yield strength of about 135,000 psi.
Dependencies are inferred from the claim text.