Timepiece mainspring of cobalt-nickel base alloys having high elasticity and high proportional limit

Claim 2

A mainspring for a timepiece composed of an alloy consisting essentially of 30-50% Co, 25-35% Ni, at least one member selected from the group consisting of Cr in the range of 6-9 percent, Mo in the range of 8-12 percent, and W in the range of 2-9 percent, the total weight of Cr, Mo and W being in the range of 15-30 percent, at least one member selected from the group consisting of Ti in the range 0.05-5 percent, Nb in the range 0.1-6 percent and Be in the range 0.01-3 percent, less that 2% Mn, less than 1.5% Si and less than 5% Fe, said alloy having been quenched for 10-90 minutes from 1,100*-1,200*C, hot-forged, hot-rolled and cold-worked to reduce the cross-section of said alloy by at least 80 percent.

Claim 3

A mainspring as defined in claim 1 wherein the W content is in the range 2-6 percent.

Claim 4

The mainspring as defined in claim 1 wherein said alloy has been age-hardened for 1-5 hours at 400*- 600*C.

Claim 5

The mainspring as defined in claim 2 wherein said mainspring has been age-hardened for 2.5-3.5 hours at 400*-600*C.

Claim 6

The mainspring as defined in claim 2 wherein said mainspring has been age-hardened for 3 hours at 400*-600*C.

Claim 7

THE PROCESS OF MANUFACTURING A MAINSPRING FOR A TIMEPIECE, COMPRISING THE STEPS OF FORMING AN ALLOY BY MELTING IN VACUUM AT A TEMPERATURE BETWEEN 1,400*C AND 1,600*C A COMPOSITION CONSISTING ESSENTIALLY OF 30-50% CO, 25-35% NI, AT LEAST ONE MEMBER SELECTED FROM THE GROUP CONSISTING OF CR IN THE RANGE OF 6-9 PERCENT, MO IN THE RANGE OF 8-12 PERCENT, AND W IN THE RANGE OF 2-9 PERCENT, THE TOTAL WEIGHT OF CR, MO AND W BEING IN THE RANGE OF 15-30 PERCENT, AT LEAST ONE MEMBER SELECTED FROM THE GROUP CONSISTING OF TI IN THE RANGE 0.05-5 PERCENT, NB IN THE RANGE 0.1-6 PERCENT AND BE IN THE RANGE 0.01-3 PERCENT, LESS THAN 2% MN, LESS THAN 1.5% SI AND LESS THAN 5% FE, QUENCHING SAID ALLOY FOR 10-90 MINUTES FROM 1,100*-1,200*C HOT-FORGING, HOT-ROLLING AND COLD-PROCESSING SAID ALLOY TO REDUCE THE CROSS-SECTIONAL AREA BY AT LEAST 80 PERCENT.

Claim 8

THE PROCESS OF MANUFACTURING A MAINSPRING FOR A TIMEPIECE, COMPRISING THE STEPS OF FORMING AN ALLOY BY MELTING IN VACUUM AT A TEMPERATURE BETWEEN 1,400*C AND 1,600*C A COMPOSITION CONSISTING ESSENTIALLY OF 30-50% CO, 25-35% NI, AT LEAST ONE MEMBER SELECTED FROM THE GROUP CONSISTING OF CR IN THE RANGE OF 6-9 PERCENT, MO IN THE RANGE OF 8-12 PERCENT, AND W IN THE RANGE OF 2-9 PERCENT, THE TOTAL WEIGHT OF CR, MO AND W BEING IN THE RANGE OF 15-30 PERCENT, AT LEAST ONE MEMBER SELECTED FROM THE GROUP CONSISTING OF TI IN THE RANGE 0.05-5 PERCENT, NB IN THE RANGE 0.1-6 PERCENT AND BE IN THE RANGE 0.01-3 PERCENT, LESS THAN 2% MN, LESS THAN 1.5% SI AND LESS THAN 5% FE, QUENCHING SAID ALLOY FOR 10-90 MINUTES FROM 1,100*-1,200*C HOT-FORGING, HOT-ROLLING AND COLD-PROCESSING SAID ALLOY TO REDUCE THE CROSS-SECTIONAL AREA BY AT LEAST 80 PERCENT.

Claim 9

The process as defined in claim 6, wherein the W content of said alloy is in the range 2-6 percent.

Claim 10

The process as defined in claim 6, further comprising the step of age-hardening said alloy for 1-5 hours at 400*-600*C.

Claim 11

The process as defined in claim 6, wherein said alloy is age-hardened for 2.5-3.5 hours at 400*-600*C.

Claim 12

The process as defined in claim 6 wherein said alloy is age-hardened for 3 hours at 400*-600*C.