Classifications

• • C—CHEMISTRY; METALLURGY
  • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
  • C22C—ALLOYS
  • C22C38/00—Ferrous alloys, e.g. steel alloys
  • C22C38/18—Ferrous alloys, e.g. steel alloys containing chromium
  • C22C38/40—Ferrous alloys, e.g. steel alloys containing chromium with nickel
  • C22C38/42—Ferrous alloys, e.g. steel alloys containing chromium with nickel with copper

Definitions

• This invention relates to a steel having high sea-water corrosion resistibility and more particularly directed to a steel having excellent weldability.
• S Mariner Steel is generally employed as good sea-water corrosion resisting steel for the so-called splash zone and in an environment where the metal is alternately wet and dry.
• the features of said US. S Mariner Steel lie in that the chemical composition consists in a P-Cu-Ni system. It is confirmed that the above steel has greater resistance to seawater splash zone corrosion and longer life in a marine environment. It is, however, an undeniable fact that there is a knotty point in the weldability of said US. S. Mariner Steel.
• the present steel is developed in order to work out said welding problem.
• the first feature of this present steel lies in that P content is limited to the range of unavoidable impurities. Accordingly, corrosion resistibility, high strength and long life in a marine environment is assured by which the chemical composition consists in a Cu-Cr-Al-Ni system. This is the second feature of this present steel. Still more, when Sb, Sb+Sn or Sb+As is added to the above composition, said properties of this invention steel are possible to be improved.
• An object of this invention is to provide a sea-water corrosion resisting steel having higher weldability.
• Another abject of this invention is to provide a seawater corrosion resisting steel with which the resistibility is superior to other steels.
• the basic composition of this invention is as follows:
• the second composition of this invention consists in adding 0.05 to 0.20% Sb to the above composition.
• the third composition of this invention consists in adding 0.05 to 0.10% Sn to the second composition.
• the fourth composition of this invention consists in adding 0.05 to 0.10% As to the second composition.
• Si content should be limited to the range in which a change of weldability for the worse can be avoided. Otherwise, hardness of said steel will increase and cracking of said steel will be brought about.
• Maximum 0.60% Si is determined for the above mentioned reasons. Such Si content is enough to deoxidize said steel and keep the strength of said steel.
• More than 1.50% Mn brings about an unnecessary increase of said strength and makes workability of said steel worse.
• P is an element for improving sea-water corrosion resistibility in coexistence with Cu.
• P also is an element making remarkably worse.
• P content of this invention should be kept within range of unavoidable impurities, i.e., less than 0.04%. While S also makes said steel worse and the upper limit is 0.04%.
• the sea-water corrosion resistibility can be remarkably improved owing to coexistence of Cu, Cr and Al. This is the biggest feature of this invention. According to many experiments, it is confirmed that the coexistance of Cu, Cr and Al shows excellent multiplied effects as mentioned hereafter;
• the content of said alloying elements is as follows respectively:
• a sea-water corrosion resisting steel for welding structures composed of maximum 0.20% C, less than 0.60% Si, maximum 1.50% Mn, up to 0.04% P and S, 0.20 to 0.60% Cu, 0.50 to 3.0% Cr, 0.30 to 3.0% A1, 0.20 to 0.50%, Ni, 0.05 to 0.15% Sb, 0.05 to 0.10% As,
• the corrosion rate is shown as a ratio to which that of common steel is 100%.

Landscapes

• Chemical & Material Sciences (AREA)
• Engineering & Computer Science (AREA)
• Materials Engineering (AREA)
• Mechanical Engineering (AREA)
• Metallurgy (AREA)
• Organic Chemistry (AREA)
• Heat Treatment Of Steel (AREA)
• Arc Welding In General (AREA)

Applications Claiming Priority (1)

Publications (1)

Family

ID=12036893

Family Applications (1)

Country Status (8)

Cited By (10)

Families Citing this family (1)

Family Cites Families (1)

• 1969
  • 1969-03-20 JP JP44020791A patent/JPS4925527B1/ja active Pending
• 1970
  • 1970-03-19 NL NL7003894A patent/NL7003894A/xx unknown
  • 1970-03-20 GB GB03687/70A patent/GB1293204A/en not_active Expired
  • 1970-03-20 US US21506A patent/US3684493A/en not_active Expired - Lifetime
  • 1970-03-20 BE BE747661D patent/BE747661A/xx unknown
  • 1970-03-20 CA CA078053A patent/CA924130A/en not_active Expired
  • 1970-03-20 DE DE19702013550 patent/DE2013550A1/de active Pending
  • 1970-03-20 FR FR7009989A patent/FR2039740A5/fr not_active Expired

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