| 摘要 |
In the present invention, there is disclosed a method of making end section of a spark plug central electrode (1) with deposit (4) of excess material using laser deposition welding method, where the central electrode (1) made of Ni alloy is first adjusted to a required length and the face (2) thereof is leveled and cleaned. Subsequently, the base material of the central electrode (1) is then locally heated by the action of a laser beam above the malting temperature thereof, whereupon excess material in the form of a powder is supplied into the laser beam and the thus formed melt, which melts down onto the surface of the central electrode (1), diffusion-mixes with the material thereof and further supply of the excess material powder gradually forms weld deposit of the pure excess material. First, the face (2) of the central electrode (1) is heated by a laser beam with reduced intensity within the range of 100 W/mme2 for a period of 0.1 s, whereupon the laser beam intensity increases in time of 0.1 to 0.3 to 600 to 800 W/mme2, to thereby heat the central electrode (1) face (2) above the melting temperature of the material thereof and powder of the excess material is supplied axially with the laser beam into the thus formed melt. The excess material powder is selected from the group consisting of W, Pt and Ir, The supply of the excess material powder creates metallurgical bond (5) between the powder and the central electrode (1), heat of this process point is vigorously removed into the central electrode (1) body to thereby causing solidification of the melt and in the repeated cycle of its further melting and solidification within the period of 0.3 to 1 s there is created a deposit (4) of the excess material of substantially spherical form to a required height. Subsequently, in this phase laser beam intensity is continuously reduced to thereby minimizing in this end of the central electrode (1) the occurrence of tension stresses and a risk of occurrence of cracks and preventing occurrence of a hard and brittle structure, whereby the central electrode (1) face (2) is shaped to final form. |
