The melting point of lead-free solder depends on the alloys that have been used to make the solder. The most popular lead-free solder is the tin-silver-copper solder, which melts at 423 degrees Fahrenheit. Tin-copper solder melts at 441 F, and tin-silver solder melts at 430 F.
Lead-free solder tends to be weaker than lead solder, so it can cause short life cycles of products. Higher amounts of tin in the solder increase the likelihood of the formation of tin whiskers, which can cause short circuits between adjacent conductors. This problem has led to some military platforms banning the use of lead-free solder.