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
  • C22C38/20—Ferrous alloys, e.g. steel alloys containing chromium with copper

Definitions

• This invention relates to a stainless steel and more particularly to a stainless steel having good rust resistant a properties but which does not require a large proportion of expensive alloying elements such as molybdenum.
• Stainless steel has become generally recognized as a steel which includes more than of chromium but the term is used in this specification to include steels which have any effective amount of chromium in their composition and it is to be understood that an effective amount of chromium as far as rust resistance is concerned is 1% or more. Where percentages of constituents are referred to hereinafter it will be appreciated that these are given as percentages by weight.
• a stainless steel having a constituent composition of at least iron, an effective quantity of chromium, a minimum vanadium content of 0.3% and a carbon content which is below a maximum 0.03%.
• iron-copper phase diagram indicates that up to 8% of copper is soluble in austenite, and therefore under equilibrium conditions iron-copper alloys up to this composition and of low carbon content should be forgeable in the normal industrial range of 1l001200 C. Alloys containing larger amounts of copper have a duplex structure; the copper rich phase is molten above 1094 C. and incipient melting of the alloys takes place if they are exposed to temperatures above this. In practice, iron-copper alloys containing very considerably less than 8% of copper are subject to incipient melting when exposed to temperatures above 1094 C. and even in some cases below this temperature.
• the copper-rich phase is very difficult to remove because the rate of diffusion of copper in iron is low below 1100 C. Hot-working helps, but if the amount of copper-rich phase is large the metal disintegrates, so that the alternatives are either to prevent the formation of the low melting point phase by adjusment of composition or hot-work only below its melting point.
• the stainless steel of the type specified includes copper as an alloying element in a quantity in excess of 2.5 and for the percentage of vanadium in the steel to increase with increased copper content.
• the invention also provides for the vanadium to be obtained and introduced directly into the steel from an ore containing vanadium such as a Transvaal type titaniferous magnetite.
• a still further feature of this invention provides for the steel to be made by the process set forth in our patent application Ser. No. 355,895.
• this invention provides a stainless steel which includes appreciable quantities of vanadium and also the very low carbon content which features enable a product to be obtained which has desirable rust resistant properties and at a highly competitive price when made in accordance with the process of our previous patent application Ser. No. 355,895. It will also be clear to those skilled in the art that for certain purposes, the advantageous properties obtainable through the inclusion in very low carbon content stainless steel of vanadium in the range 0.3% to 2.0% and copper in the tectural cladding purposes the steel will have a composition consisting essentially of:
• the balance being iron and the carbon content being below 0.03%.
• a stainless steel consisting essentially of 1% to 30% chromium; 0.3% to 2.0% vanadium; 2.5% to 4% copper; up to 0.03% carbon, the balance being iron, all percentages being by weight of the composition.

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• Chemical & Material Sciences (AREA)
• Engineering & Computer Science (AREA)
• Materials Engineering (AREA)
• Mechanical Engineering (AREA)
• Metallurgy (AREA)
• Organic Chemistry (AREA)
• Heat Treatment Of Steel (AREA)
• Treatment Of Steel In Its Molten State (AREA)

Applications Claiming Priority (1)

Publications (1)

Family

ID=25560848

Family Applications (1)

Country Status (6)

Citations (13)

• 1965
  • 1965-08-30 US US483826A patent/US3377162A/en not_active Expired - Lifetime
  • 1965-09-08 ES ES0317217A patent/ES317217A1/es not_active Expired
  • 1965-09-09 NL NL6511773A patent/NL6511773A/xx unknown
  • 1965-09-10 BE BE669439D patent/BE669439A/xx unknown
  • 1965-09-10 AT AT829965A patent/AT271534B/de active
  • 1965-09-10 GB GB38804/65A patent/GB1084877A/en not_active Expired

Patent Citations (13)

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