Abstract An inexpensive but improved composite strip material for use in making resilient electrical contact arms and the like is shown to comprise a strip of composite, electrically-conductive spring material having a layer of copper metallurgically bonded between outer layers of hardened stainless steel, at least one of these stainless steel layers having a stripe of solder adhered to the stainless steel material extending along the length of the composite spring material and preferably having a stripe of precious metal material displaying low electrical contact surface resistance properties extending along the length of the spring material. The solder stripe is provided on the stainless steel surface of the spring material by fluxing the stainless steel surface, by depositing a molten solder stripe on the fluxed strip surface, and by rapidly chilling the spring material as the solder is deposited thereon for solidifying the solder stripe in such a way as to assure adherence of the solder stripe to the stainless steel spring surface.
A composite strip material as set forth in claim 1 wherein said stainless steel layers of said spring material embody at least partially hardened stainless steel alloys selected from the group of alloys comprising an alloy having an approximate composition by weight of 0.09 percent (max.) carbon, 1.00 percent (max.) manganese, 1.00 percent (max.) silicon, 14.00 to 16.00 percent chromium, 6.50 to 7.75 percent nickel, 2.00 to 3.00 percent molybdenum, 0.75 to 1.50 percent aluminum and the balance iroN and an alloy having an approximate composition by weight of 0.15 percent (max.) carbon, 2.00 percent (max.) manganese, 1.00 percent (max.) silicon, 16.00 to 18.00 percent chromium, 6.00 to 8.00 percent nickel, 0.045 percent (max.) phosphorous, 0.030 percent (max.) sulfur, and the balance iron, said stainless steel layers being of substantially equal thickness comprising from about 25 to 38 percent of the total thickness of said composite spring material.
Claim 2
Dependent Claim
228 words
A composite strip material for use in making electrical contact arms and the like comprising a strip of composite electrically conductive spring material having a layer of copper sandwiched between and metallurgically bonded to two outer layers of stainless steel, said stainless steel layers of said spring material embodying at lease partially hardened stainless steel alloys selected from the group of alloys comprising an alloy having an approximate composition by weight of 0.09 percent (max.) carbon, 1.00 percent (max.) manganese, 1.00 percent (max.) silicon, 14.00 to 16.00 percent chromium, 6.50 to 7.75 percent nickel, 2.00 to 3.00 percent molybdenum, 0.75 to 1.50 percent aluminum and the balance iron and an alloy having an approximate composition by weight of 0.15 percent (max.) carbon, 2.00 percent (max.) manganese, 1.00 percent (max.) silicon, 16.00 to 18.00 percent chromium, 6.00 to 8.00 percent nickel, 0.045 percent (max.) phosphorous, 0.030 percent (max.) sulfur, and the balance iron, said stainless steel layers being of substantially equal thickness comprising from about 25 to 38 percent of the total thickness of said composite spring material, said spring material having a stripe of gold secured to said spring material extending along the length of said strip of spring material and at least one of said stainless steel layers having a stripe of solder material continuously adhered thereto extending along the length of said strip of spring material.