| 摘要 |
High-strength, electric seam-welded pipe for use in oil wells are produced from steel contg. (wt.%) 0.08-0.26 C, 0.8-1.9 Mn, 0.10-0.5 Si, 0-0.5 Nb, 0-0.5 V, 0-0.03 T, 0-0.0020 B, remaindr Fe and unavoidable impurities. The steel is hot rolled to sheet, which is quenched from the austenitic phase to refine the ferrite grain at about 850 deg.C. The hardened steel sheet is coiled at a temp. not more than 250 deg.C. The sheet is formed to pipe dia. required and welded. Only the welded zone is reheated to a temp. above 900 deg.C by induction heating and the reheated zone is quenched. The whole pipe is tempered.
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