Steel well casing and method of production
AssigneeRepublic Steel Corporation
InventorsGeorge M. Waid, Robert T. Ault
Life of this patent
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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.
Claims8
A process of making well casing characterized by improved hydrogen sulfide stress cracking resistance at high yield strengths ranging from about 90 to 145 ksi comprising the steps of providing an aluminum-killed steel consisting essentially in amounts by weight of from 0.10 to 0.40% carbon, 0.25 to 0.75% manganese, 0.05 to 0.50% silicon, 1.0 to 5.0% chromium, 0.30 to 1.0% molybdenum, 0.05 to 0.55% vanadium, 0.02 to 0.10% aluminum, and the balance iron except normal steel making impurities;
- rolling and forming the steel into tubular form;
- austenitizing the casing at a temperature of from 1550.degree. to 1700.degree. F., quenching the casing to obtain a microstructure which is essentially martensite, and tempering the casing at a temperature of from 1200.degree. to 1400.degree. F. to a maximum hardness of 35 R.sub.C and a microstructure which is essentially tempered martensite.
A process of making well casing characterized by improved hydrogen sulfide stress cracking resistance at high yield strengths ranging from about 90 to 145 ksi comprising the steps of providing an aluminum-killed steel consisting essentially in amounts by weight of from 0.15 to 0.35% carbon, 0.35 to 0.65% manganese, 0.10 to 0.35% silicon, 1.5 to 3.0% chromium, 0.40 to 0.80% molybdenum, 0.10 to 0.30% vanadium, about 0.02 to 0.08% aluminum, and the balance iron except normal steel making impurities;
- rolling and forming the steel into tubular form;
- austenitizing the casing at a temperature of from 1550.degree. to 1700.degree. F.;
- quenching the casing to obtain a microstructure which is essentially martensite, and tempering the casing at a temperature of from 1200.degree. to 1400.degree. F. to a maximum hardness of 35 R.sub.C and a microstructure which is essentially tempered martensite.
Quenched and tempered well casing characterized by improved hydrogen sulfide stress cracking resistance at high yield strengths ranging from about 90 to 145 ksi comprising an aluminum-killed steel consisting essentially in amounts by weight of from 0.10 to 0.40% carbon, 0.25 to 0.75% manganese, 0.05 to 0.50% silicon, 1.0 to 5.0% chromium, 0.30 to 1.0% molybdenum, 0.05 to 0.55% vanadium, 0.02 to 0.10% aluminum, and the balance iron except normal steel making impurities, the steel having a maximum hardness of 35 R.sub.C and a microstructure which is essentially tempered martensite.
Quenched and tempered well casing characterized by improved hydrogen sulfide stress cracking resistance at high yield strengths ranging from about 90 to 145 ksi comprised of an aluminum-killed steel consisting essentially in amounts by weight of from 0.15 to 0.35% carbon, 0.35 to 0.65% manganese, 0.10 to 0.35% silicon, 1.5 to 3.0% chromium, 0.40 to 0.80% molybdenum, 0.10 to 0.30% vanadium, about 0.02 to 0.08% aluminum, and the balance iron except normal steel making impurities, the steel having a maximum hardness of 35 R.sub.C and a microstructure which is essentially tempered martensite.
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