Linepipe and structural steel produced by high speed continuous casting
AssigneeAmerican Cast Iron Pipe Company
InventorJohn Malcolm Gray
Life of this patent
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Abstract
A high strength, high toughness, low carbon/low manganese steel is provided that is further resistant to stepwise cracking and sulfide stress cracking. The steel can be produced by conventional or thin slab casting techniques using normal speeds, with low manganese segregation levels. The steels are excellent candidates for linepipe applications in severe sour gas service.
Claims23
A high strength steel exhibiting a microstructure substantially free of coarse grained ferrite comprising:
- carbon in a range of about 0.015-0.080 weight percent;
- manganese in a range of about 0.10-1.0 weight percent;
- sulfur in a range of about <0.008 weight percent
- wherein the high strength steel has a yield strength, in a hot-rolled condition in the range of about 36 ksi to about 80 ksi.
A high strength steel exhibiting a microstructure substantially free of coarse grained ferrite comprising:
- ______________________________________ Element Range (wt. %) ______________________________________ C 0.015-0.080 Mn 0.10-1.0 Nb (Cb) 0.005-0.15 Ti 0.005-0.030 Cr .ltoreq.0.50 Ni .ltoreq.0.95 Mo .ltoreq.0.60 B .ltoreq.0.0025 S .ltoreq.0.008 N 0.001-0.010 Ca .ltoreq.0.0050 P .ltoreq.0.025 ______________________________________
A hydrogen-induced cracking (HIC) resistant linepipe steel comprising:
- ______________________________________ Element Range (wt. %) ______________________________________ C 0.015-0.080 Mn 0.10-1.0 Nb (Cb) 0.005-0.15 Ti 0.005-0.030 Cr .ltoreq.0.50 Ni .ltoreq.0.95 Mo .ltoreq.0.60 B .ltoreq.0.0025 S .ltoreq.0.008 N 0.001-0.010 Ca .ltoreq.0.0050 P .ltoreq.0.025 ______________________________________
A high strength steel comprising:
- carbon in a range of about 0.015-0.080 weight percent;
- manganese in a range of about 0.10-0.23 weight percent;
- sulfur in a range of about .ltoreq.0.008 weight percent;
- wherein the high strength steel has a yield strength in the range of about 36 ksi to about 80 ksi.
A high strength steel comprising:
- carbon in a range of about 0.015-0.080 weight percent;
- manganese in a range of about 0.10-1.0 weight percent;
- sulfur in a range of .ltoreq.0.008 weight percent;
- about 0.03-0.15 weight percent niobium (columbium);
- wherein the high strength steel has a yield strength in the range of about 36 ksi to about 80 ksi.
A high strength steel comprising:
- carbon in a range of about 0.015-0.080 weight percent;
- sulfur in a range of about .ltoreq.0.008 weight percent;
- wherein said steel is substantially free of molybdenum, and
- wherein said steel has a yield strength in the range of about 36 ksi to about 80 ksi.
Dependencies are inferred from the claim text.