| 摘要 |
LOW ALLOY STEEL, SEAMLESS STEEL OIL COUNTRY TUBULAR GOODS, AND METHOD FOR PRODUCING SEAMLESS STEEL PIPE 5 A LOW ALLOY STEEL COMPRISING, BY MASS , C : 0. IO TO 0.20, SI : 0.05 TO 1.0, MN : 0.05 TO 1.5, CR: 1.0 TO 2.0, MO :0.05 TO 2.0, AL : 0.10 OR LESS AND TI :0.002 TO 0.05, AND WITH A CEQ VALUE OBTAINED BY THE FOLLOWING FORMULA (1) OF 0.65 OR MORE, WITH THE BALANCE BEING FE AND IMPURITIES, WHEREIN IN THE IMPURITIES, P IS 0.025OR LESS, S IS 0.010OR LESS, N IS 0.007OR LESS, AND B IS LESS THAN 0.0003, AND THE NUMBER PER UNIT 10 AREA OF M23C6 TYPE PRECIPITATES (M: A METAL ELEMENT) WHOSE GRAIN DIAMETER IS I JTRN OR MORE ISO.1/MYRI?ORLESS. TLIISINVENTIONPROVIDESALOWALLOYSTEELPOSSESSINGBOTH HARDENABILITY AND TOUGHNESS AND IMPROVES THE RESISTANCE TO SULFIDE STRESS CORROSION CRACKING. CEQ = C + (MN/6) + (CR +MO +V)/5 FORMULA (1) 1 5 -WHERE C, MN, CR, MO AND V IN THE FORMULA (1) DENOTE THE MASS OF RESPECTIVE ELEMENTS.
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