Manufacture of electrically welded steel pipe
US4410369A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Dec 12, 1980 |
| Grant date | Oct 18, 1983 |
| Priority date | — |
| Expiry date | Dec 12, 2000 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY10T428/12965
- WIPO fieldMaterials, metallurgy
- WIPO sectorChemistry
Abstract
For skelp to make pipe having a seam butt-joined as by electrical resistance or submerged arc welding, skelp is made by pouring a base melt of rimming steel into an ingot mold to about 80 to 95% full and then after a shell of rimmed steel has solidified against the mold wall, completing pouring of the same melt while adding further material to the molten core, e.g. more C or Mn, and Al or the like for killing, so that the solidified ingot has a core of desired high strength, killed or semi-killed steel. The ingot is processed to desired skelp by hot rolling, the top and bottom regions being suitably cropped, so that the skelp has a main body of the high strength steel, bordered lengthwise by integral edge zones, e.g. 1/2 inch or more wide, of the rimmed steel, free of unwanted inclusions. When rolled to pipe shape, with finished edges, the edge zones are electrically butt welded, such operation being effected with unusual facility. In the completed pipe, the weld region is relatively free of oxide or like inclusions, and thus not susceptible of rejection for defects at or about the seam, while the pipe is essentially characterized by high wall strength.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.