| 摘要 |
Abst ract seamless ~ ~ ~ Son qeceantmprd Stel wip having a wail thicknessVI (WTr tha o equal to 3 m and lower than or equ to 80 mm, wherein the steel pipe has a chemical composition consisting of I&50-0085 wtC 0.80.6 wt% Mn, 010-045 wt% Si 010-00 wt% (I (08-04 wt% Ni,008-040 wt% Mo, 0.0.5-0.040 wt% AlO.008-00050 wt% Ca, 000 0A 0vt% N. 0.00A04 wt% Nb, 000-0.02 wt Ti 0001030 wt% Zr, 0000.030 t% Ta based on the composition weight, the remaining being iron and impurities; said impurities comprising 0,000>00 wt% V; wherein, defining a first parameter P1i = 50 x C + Cr + 10 x Moa ± 0 a V. the chemical composition satisfies a first condition P1 1 8.; wherein the quenched and tempered steel pipe has at md thinss, a iosetruature comprising, in volume percentage, tempered bainite geater than or equal to 50% and ferriteMy5 tower than or equal to 50%; wherein the quenched and tempered steel pipe has at a distance up to 2 mm starting from outer and inner surfaces of the steel pipe, a nmirostrueture consisting of in volurre perentage, tempered martensitelower than 70% and tempered haine higher than A0% and wheMin the maximum hardness values, measured at 1.5-20 mm depth from the outer and inner surfaces are below 2351W10 "'A N' ""'3 ''$ 3 3~4 /zZ< ~~t' 1<' I~. >1~ rc;~ -3 ~ 3 4 4 ~'4 N. 'Nt N' s 7 ( '~"'t "A k I ~ /'~ 'N 3$ '44 ("3 "'> r~ t"N ~"> 'N'N ""N c' / N'~' S"'/ x'~' /~s -' /"" N' '~'N r~'~ Y'~ ~'N'/ "NS 'zN't' kNfl N" ""N kNx0 ~ ' NT SN'> / 4Ct "N - |
