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
  • C22C38/50—Ferrous alloys, e.g. steel alloys containing chromium with nickel with titanium or zirconium
• • C—CHEMISTRY; METALLURGY
  • C21—METALLURGY OF IRON
  • C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
  • C21D8/00—Modifying the physical properties of ferrous metals or ferrous alloys by deformation combined with, or followed by, heat treatment
  • C21D8/06—Modifying the physical properties of ferrous metals or ferrous alloys by deformation combined with, or followed by, heat treatment during manufacturing of rods or wires

Definitions

• the present invention relates to low alloy steel wire.
• the mechanical properties of drawn carbon-steel wire can be manipulated and controlled by subjecting the wire to oil quench hardening and tempering. It would be desirable to be able to treat low alloy steel so as to'produce wire which has better mechanical'properties than oil quench hardened and tempered wire, espe- 2 (preferably 28 percent); heating the wire leaving the die to 300450C (preferably 420C and forcibly cooling the wire.
• the heat treatment to produce the pearlite structure lower relaxation- 10 preferably comprises heating above the AC point
• Great Britain Pat. No. 748,357 describes a method ofli to d h ldi t a temperature b tw 550 treating cold drawn wire, in which the wire is drawn to d 700C h preferred temperature b i 50C f its final Size in a die and, as 1631/65 the 118,15 heated lowed by cooling in air.
• the material is first given a heat treatment involving heating to a temperature 50-150C above the AC point, air cooling to just above the Ms point, and reheating to 450-650C, followed by air cooling. Then follows multi-hole cold drawing to the finished size, with a reduction in area of at least 40 percent.
• the finished wire is tempered, preferably at 440C or higher, without tensile stress or quenching.
• the steel has a high silicon content.
• the present invention provides a method of producing low alloy steel wire from low alloy steel rod, the method comprising heat treating the rod to produce a pearlite structure; cold drawing the rod to initiate work hardening and thereby raise the tensile strength; drawing the part-drawn rod through a drawing die to reduce As-rolled rod (5 mm diameter) of each steel composition was initially austenitised, cooled to 650C and held at this temperature, and then allowed to cool in air; this provided a pearlite structure. The rod was cleaned, provided with a drawing coat, and drawn to a diameter of 4.4 mm; this initiated work hardening and raised the tensile strength.
• the part-drawn rod was then further drawn, during which operation it was subjected to a reduction in area of 25 percent, to finish at 3.85 mm diameter. As soon as the wire emerged from the die, it was heated to 420C and then quenched from this temperature by forcible cooling using an air blast or water spray.
• the resulting wire had a tensile strength ranging from 158 to 175 kgf/mm
• the mechanical properties of the wire obtained from each steel composition are shown in Table 11.
• the properties of the as drawn wire (not the cross-sectional area by between 10 and 40 percent heated after drawing) are shown for comparison.
• low temperature heat treatment under tension may promote a dislocation locking mechanism involving interstitial carbon and nitrogen atoms, creating a condition similar to strain ageing.
• Additions of such alloying elements as chromium, silicon, and vanadium may promote an interaction between dislocations and alloy carbides, resulting in a further increase in flow stress.
• the rod can be given the pearlite structure by a heat treatment comprising controlled cooling of the rod as it leaves the hot rolling mill.
• a method of producing low alloy steel wire from low alloy steel rod comprising heat treating the rod to produce a pearlite structure; cold drawing the rod to initiate work hardening and thereby raise the tensile strength; drawing the part-drawn rod through a drawing die to reduce the cross-sectional area by between 10 and 40 percent; heating the wire leaving the die to 300450C; and forcibly cooling the wire.
• a method as claimed in claim 1, in which the heat treatment to produce a pearlite structure comprises heating above the AC point, cooling to and holding at a temperature between 550 and 700C, and then cooling in air.
• alloying elements selected from the following elements in the following ranges: Mn 0.20-l.50%, Si 0.l0-4.00%, Cr 0.l04.00%, S 0.050% maximum, P 0.050% maximum, Mo 0.l02.00%, Cu 0.l0-3.00%, Ni 0.l0-5.00%, Ti

Landscapes

• Chemical & Material Sciences (AREA)
• Engineering & Computer Science (AREA)
• Materials Engineering (AREA)
• Mechanical Engineering (AREA)
• Metallurgy (AREA)
• Organic Chemistry (AREA)
• Manufacturing & Machinery (AREA)
• Physics & Mathematics (AREA)
• Thermal Sciences (AREA)
• Crystallography & Structural Chemistry (AREA)
• Heat Treatment Of Strip Materials And Filament Materials (AREA)
• Heat Treatment Of Steel (AREA)
• Metal Extraction Processes (AREA)

Applications Claiming Priority (1)

Publications (1)

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ID=10465383

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Country Status (5)

Cited By (9)

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Citations (6)

• 1972
  • 1972-11-15 GB GB5280572A patent/GB1400872A/en not_active Expired
• 1973
  • 1973-11-13 SE SE7315320A patent/SE387369B/xx unknown
  • 1973-11-14 DE DE2356791A patent/DE2356791A1/de active Pending
  • 1973-11-15 US US00416203A patent/US3844848A/en not_active Expired - Lifetime
  • 1973-11-15 JP JP48128675A patent/JPS5046511A/ja active Pending

Patent Citations (6)

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