Claims
- 1. A high toughness, ultra high strength steel used in a deep-sea environment having a yield strength of not less than 110 kgf/mm.sup.2, a Charpy V-notch absorbed energy at -70.degree. C. of not less than 10 kgf.m and a stress corrosion cracking resistance (K.sub.ISCC) of not less than 500 kgf mm.sup.-3/2 at parent metal and not less than 350 kgf mm.sup.-3/2 at weld heat-affected zone, consisting of 0.06-0.20% by weight of C, not more than 0.35% by weight of Si, 0.05-1.00% by weight of Mn, 9.6-11% by weight of Ni, 0.2-1.5% by weight of Cr, 0.7-2.5% by weight of Mo, 0.05-0.2% by weight of V, 0.01-0.08% by weight of Al, not more than 0.005% by weight of N, not more than 0.003% by weight of O, provided that the value of Al(%).times.N(%).times.10.sup.4 is not more than 1.5, and the balance being substantially Fe and inevitable impurities.
- 2. A high toughness, ultra high strength steel used in a deep-sea environment having a yield strength of not less than 110 kgf/mm.sup.2, a Charpy V-notch absorbed energy at -70.degree. C. of not less than 10 kgf.m and a stress corrosion cracking resistance (K.sub.ISCC) of not less than 500 kgf mm.sup.-3/2 at parent metal and not less than 350 kgf mm.sup.-3/2 at weld heat-affected zone, consisting of 0.06-0.20% by weight of C, not more than 0.35% by weight of Si, 0.05-1.00% by weight of Mn, 9.6-11% by weight of Ni, 0.2-1.5% by weight of Cr, 0.7-2.5% by weight of Mo, 0.05-0.2% by weight of V, 0.01-0.08% by weight of Al, not more than 0.005% by weight of N, not more than 0.003% by weight of O, and at least one element of not more than 2% by weight of Cu, not more than 0.1% by weight of Nb, not more than 0.05% by weight of Ti, not more than 0.1% by weight of Zr, not more than 0.1% by weight of Ta and not more than 1% by weight of W, provided that the value of Al(%).times.N(%).times.10.sup.4 is not more than 1.5, and the balance being substantially Fe and inevitable impurities.
Priority Claims (1)
Number |
Date |
Country |
Kind |
59-251167 |
Nov 1984 |
JPX |
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Parent Case Info
This application is a continuation of application Ser. No. 801,577, filed Nov. 25, 1985, now abandoned.
US Referenced Citations (2)
Number |
Name |
Date |
Kind |
3620717 |
Sekino et al. |
Nov 1971 |
|
4152148 |
Machmeier |
May 1979 |
|
Foreign Referenced Citations (1)
Number |
Date |
Country |
56-9358 |
Jan 1981 |
JPX |
Continuations (1)
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Number |
Date |
Country |
Parent |
801577 |
Nov 1985 |
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