FIELD: metallurgy.
SUBSTANCE: invention relates namely to flexible steel pipes and methods for manufacturing flexible steel pipes. The flexible steel pipe comprises steel strips end-to-end butt-welded with fillet welds and formed into a pipe by welding, each strip being made of C-Mn steel, B-Ti steel or Cr-Mo steel. The pipe has areas of the base metal, welds and their heat-affected zones. The pipe has a yield strength in excess of 80 ksi and a final microstructure containing a mixture of tempered martensite and bainite. At the same time, the final microstructure of the flexible pipe in all areas of the base metal, on welds and in heat-affected zones, consisting of tempered martensite more than 90% by volume, is homogeneous with a grain size of less than 20 mcm, and has a uniform distribution of fine-grained carbides.
EFFECT: resulting flexible pipes are characterized by high strength.
17 cl, 18 dwg, 6 ex
| Title | Year | Author | Number |
|---|---|---|---|
| HIGH-QUALITY MATERIAL FOR FLEXIBLE LONG PIPES AND METHOD OF MANUFACTURE THE SAME | 2014 |
|
RU2664347C2 |
| FLEXIBLE TUBE WITH VARIABLE MECHANICAL PROPERTIES AND METHOD OF MAKING SAME BY CONTINUOUS HEAT TREATMENT | 2012 |
|
RU2582326C2 |
| HOT-ROLLED STEEL SHEET FOR COILED TUBING | 2017 |
|
RU2712159C1 |
| STEEL WELDED PIPE OBTAINED BY CONTACT WELDING FOR FLEXIBLE CONTINUOUS PIPE AND METHOD OF ITS PRODUCTION | 2017 |
|
RU2710817C1 |
| STEEL WITH HIGH RUPTURE RESISTANCE AND PROCESS OF PRODUCTION THEREOF | 1998 |
|
RU2205245C2 |
| HIGH-STRENGTH WELDABLE STEEL AND ITS VERSIONS | 1996 |
|
RU2136775C1 |
| SULPHUR-RESISTANT PIPE FOR A PETROLEUM BOREHOLE ATTRIBUTED TO THE KILOPOUND/INCH (862 MPa) STEEL STRENGTH CLASS, AND METHOD FOR MANUFACTURE THEREOF | 2019 |
|
RU2763722C1 |
| HIGH-STRENGTH STEEL STRIP AND METHOD FOR PRODUCTION THEREOF | 2013 |
|
RU2711698C2 |
| SUPERHIGH STRENGTH CRYOGENIC WELDED JOINTS | 1998 |
|
RU2198771C2 |
| WELDED SEAM METAL FOR JOINING HIGH-STRENGTH LOW-ALLOY STEELS | 2001 |
|
RU2275281C2 |
