Modified brass alloys with improved stress relaxation resistance
AssigneeOlin Corporation
InventorsWarren F. Smith, Jr., John M. Vitek, Eugene Shapiro
Life of this patent
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Abstract
An alloy system which exhibits improved resistance to stress relaxation at elevated temperatures utilizes additions of tin or silicon, or mixtures of each of these elements, along with magnesium or magnesium plus aluminum to a copper-zinc base to attain the stress relaxation performance. The composition and processing of this alloy system maintains at least 90% by weight alpha-phase within the alloy.
Claims16
An essentially single-phase alpha alloy which is particularly resistant to stress relaxation at elevated temperatures, said alloy consisting essentially of one component selected from the group consisting of 0.05 to 0.5% by weight magnesium or 0.05 to 0.5% by weight magnesium in combination with 0.02 to 0.5% by weight aluminum, a second component selected from the group consisting of 0.05 to 3.0% by weight silicon or 0.05 to 0.3% by weight silicon in combination with 0.1 to 2.0% by weight tin, from 8 to 32.8% by weight zinc, balance copper, with the amount of said aluminum, silicon or tin being inversely related to the amount of said zinc and with the maximum wt.% zinc=32.8 -4.8.times.(wt.% Al) -2.3.times.(wt.% Sn) -6.5.times.(wt.% Si).
A method for producing an essentially single-phase alpha alloy which is particularly resistant to stress relaxation at elevated temperatures, said method comprising the steps of:
- (a) casting an alloy consisting essentially of one component selected from the group consisting of 0.05 to 0.5% by weight magnesium or 0.05 to 0.5% by weight magnesium in combination with 0.02 to 0.5% by weight aluminum, a second component selected from the group consisting of 0.05 to 3.0% by weight silicon or 0.05 to 3.0% by weight silicon in combination with 0.1 to 2.0% by weight tin, from 8 to 32.8% by weight zinc, balance copper, with the amount of said aluminum, silicon or tin being inversely related to the amount of said zinc and with the maximum wt.% zinc =32.8 -4.8 .times.(wt.% Al) -2.3.times.(wt.% Sn) -6.5.times.(wt.% Si);
- (b) hot working said alloy at a temperature above the recrystallization temperature of the alloy and below the solidus temperature of the alloy;
- (c) cold working said alloy with up to but not including a 100% reduction in area;
- and
- (d) annealing the worked alloy at 150.degree. to 900.degree. C. to recrystallize the alloy to a grain size of 0.005 to 0.050 mm.
Dependencies are inferred from the claim text.