Electrode beam welded spark plugs for industrial electrodes

摘要

An industrial spark plug (20) includes a central electrode (24) with a central base (30) formed of a nickel-based material and a central firing tip (32) formed of an iridium-based material. The central firing tip (32) has a tip thickness (tct) of 0.02 to 0.03 inches, a tip diameter (dct) of 0.1184 to 0.1776 inches, and an aspect ratio of 4.736 to 7.104. The central firing tip (32) is electron beam welded to the central base (30) to provide a robust joint therebetween. The central electron beam weld (36) includes a mixture of re-crystallized iridium-based material and re-crystallized nickel-based material extending continuously along and over the entire welding interface. The spark plug (20) also includes a ground electrode (26) with a ground firing tip (38) electron beam welded to a ground base (42).

主权项

1. A spark plug for providing a spark to ignite a combustible mixture in a combustion chamber, comprising:
a central electrode including a central base extending longitudinally from a terminal end to a central base end, a ground electrode including a ground base extending from a shell end to a ground base end, said central electrode and said ground electrode presenting a spark gap therebetween, at least one of said electrodes including a firing tip having a tip end disposed adjacent said base end, said firing tip including opposite tip sides extending continuously from said tip end to a firing end providing said spark gap, said firing tip presenting a tip diameter extending between said opposite tip sides and a tip thickness extending from said tip end to said firing end, the spark plug being formed by a process comprising the steps of: providing said firing tip with an aspect ratio of 4.736 to 8.0 and electron beam welding said firing tip to said electrode base, said electrode including an electron beam weld between said electrode base and said tip end of said firing tip, wherein said aspect ratio of said firing tip is determined by dividing said tip diameter before welding said firing tip to said electrode base by said tip thickness before welding said firing tip to said electrode base, and said electron beam weld extending continuously between said opposite tip sides.