A process for improving the strength characteristics of a wire composed of an austenitic metal alloy selected from the group consisting of stainless steel alloys of the AISI 200 and 300 series and non-stainless steel alloys containing iron, manganese, chromium, and carbon, said alloy having an Md temperature of no higher than about 100.degree. C. and an Ms temperature of no higher than about minus 100.degree. C., comprising the following steps: (a) deforming the wire at a strain of at least about 10 percent and at a temperature in the range of about Md minus 50.degree. C. to about Md plus 50.degree. C., said Md temperature being that of the alloy undergoing deformation, in such a manner that the wire has a martensite phase of no greater than about 10 percent by volume and an austenite phase of at least about 90 percent by volume and a yield strength in the range of about 130,000 psi to about 230,000 psi; (b) cooling the wire to a temperature no higher than about minus 75.degree. C.; and (c) drawing the cooled wire through a die under back-tension (i) wherein the back-tension on said wire just prior to the entry of the wire into the die is at least about 75,000 psi and (ii) whereby the cross-sectional area of the wire is reduced by a percentage in the range of about 7 percent to about 25 percent, In such a manner that the wire has a martensite phase of at least about 50 percent by volume and an austenite phase of at least about 10 percent by volume.
A process and apparatus is provided for forming spring wire into coils. A take-up block with a peripheral surface receives convolutions of wire as it is rotated. At least one pinch roll confines convolutions of the spring wire to the peripheral surface. The shape of the peripheral surface of the block and the circumferential surface of the pinch roll combine to define a gap for urging the convolutions of spring wire to migrate upward. At least one rotatable wire receiving basket is mounted adjacent the take-up block, and further drive means are provided for rotating the at least one wire receiving basket. In a preferred form, stationary guide loops are utilized to keep the spring wire moving in a predetermined trajectory from the take-up block to the rotating wire receiving basket. Again in a preferred embodiment, there are two wire receiving baskets, both rotated at a predetermined and adjustable speed, and the wire is wrapped into a coil firstly on one of the wire receiving baskets, and then on the other of the wire receiving basket. While each wire receiving basket is being filled, the coil of wire in the other can be removed.
A process for the manufacture of martensitic stainless steel rods or machine wire, and the products thus obtained, by hot rolling, which steel comprises by % weight: C=0.015 to 0.090 N=0.015 to 0.080 with C+N=0.05 to 0.120 Cr=9.0 to 14.0 Nb=.ltoreq.0.1 V=.ltoreq.0.1 S=.ltoreq.0.35 Si=.ltoreq.1.0 Mn=.ltoreq.1.0 Ni=.ltoreq.2.0 Mo=.ltoreq.1.0 P=.ltoreq.0.040 Cu=.ltoreq.1.0 Fe and impurities=balance and having the following mechanical properties: R=900 to 1100 MPa; E 0.2=650 to 850 MPa; A.gtoreq.10%; and resilience KCU.gtoreq.40 J/cm.sup.2, and wherein the preheating or the end of the hot rough preliminary processing preceding the final hot rolling brings the products to a temperature between 1000.degree. C. and 1160.degree., and wherein the final hot rolling which is effected at a temperature below or equal to 1150.degree. C. produces a section reduction "S/s" which is at least equal to 3, and which reduction is followed by homogenous cooling and when S.ltoreq.0.08% the rods or machine wire have the following mechanical properties: R=900 to 1100 MPa; E 0.2=650 to 850 MPa; A=12 to 16%; resilience KCU=80 to 140 J/cm.sup.2, and the rods or machine wire of the invention are particularly used for the manufacture of corrosion resistant mechanisms.
A steel wire, and a method for producing the same, for use in the manufacture of a chassis or suspension automotive spring having a high sag resistance. In accordance with the invention, after a heat treatment is effected, strain is imposed to the steel wire so as to thereby improve the sag resistance. The strain may be imposed either during tempering or at room temperature following tempering.
A method for making a fastener having a head and a shank from a slug consisting essentially of an AISI 200 or 300 series stainless steel having an Md.sub.30 temperature in the range of about minus 50.degree. C. to about 50.degree. C. comprising the following steps: (a) cooling the slug to a temperature at least about 50.degree. C. below the Md.sub.30 temperature of the stainless steel minus 30.degree. C. (b) extruding a portion of the cooled slug to provide the shank while simultaneously heating the remaining portion of the cooled slug to a temperature in the range of about Md.sub.30 minus 30.degree. C. to about 500.degree. C.; and (c) upsetting the heated remaining portion to provide the head.
A wire oven rack, capable of being later-coated with porcelain, including, a plurality of elongated steel wire members joined together to form an oven rack having an outer surface. The plurality of elongated steel wire members are made from a steel rod material containing from about 80 to about 99.9% by weight of iron, from about 0.001 to about 0.08% by weight of carbon and from about 0.001 to about 0.2% by weight of a carbon stabilizing transition metal, preferably selected from the group consisting of Vanadium, Tantalum, Titanium and Niobium. The plurality of elongated steel wire members are preferably made from the steel rod material by drawing the steel rod material to form steel wire; wherein the diameter of the cross-sectional area of the steel rod material is reduced by at least about 20% when the steel rod material is drawn to form the steel wire, so as to prevent chipping of the glass coating material from the outer surface, when the porcelain coating is later applied, due to the release of hydrogen gas from the coated steel wire members when the steel wire is heated above 900.degree. F.
