Patent ID: 11904416
Assignee: SENJU METAL INDUSTRY CO., LTD.
Field: Machine tools (Mechanical engineering)
Classification: CPC B  C | IPC B  C

Claim 0:
1. A solder alloy having an alloy composition consisting of, by mass: Ag: 2.0 to 4.0%; Cu: 0.51 to 0.79%; and Bi: more than 4.0% and 7.0% or less, with the balance being Sn,
wherein the alloy composition satisfies the following relations (1), (2) and (3),

12.61≤Sn/Bi≤22.4  relation (1)

46.9≤Sn×Cu≤72.1  relation (2)

180.42≤Sn×Ag≤365  relation (3)

wherein Sn, Bi, Cu, and Ag in the relations (1), (2) and (3) each represent the mass % thereof in the alloy composition,
wherein:
the solder alloy has a solidus temperature of 190° C. to less than 217° C., and a liquidus temperature of less than 217° C.,
the solder alloy has a tensile strength in accordance with JIS Z3198-2 of 90 MPa or more, and
the solder alloy has a thermal fatigue resistance, wherein an average number of repetitive tensile cycles until breakage occurred, under evaluation conditions that a test load is 300 N in a tensile direction, a test speed is 3 mm/min, and a test temperature is 125° C., of at least three times the average number of repetitive tensile cycles using an alloy composition consisting of by mass: Ag: 3.0%, Cu: 0.5%, with the balance being Sn.