Forming of the molten bath during laser allowing of the bandage steels surface

ABSTRACT

Modern technologies for increasing wear resistance of the railway wheels do not provide the required level of this characteristic as their potential is limited by the steel properties. Creating the surface composite layer of the steel-WC system makes it possible to increase wear resistance considerably higher without significant material consumption. For effective exploitation of a composite layer, the hardening particles distribution in depth must be as homogeneous as it is possible. Heavy WC particles are considered to reach the bottom of the melted metal pool, however relatively uniform particles distribution is observed in the studied cross-sections of the samples, with decreasing the amount of particles in the central part of the reinforced track near its bottom. The experiments with the removal of the melted metal from the welding pool showed that the shape of the welding pool effects the distribution of the particles. The proportion of the projection of the layer in the area of the melt surface is insignificant, thus it should be assumed that when the powder flow is coaxial to the laser beam, the effective particles injection into the near-bottom layer is limited by the angle of the particles movement to the melted metal surface.

KEYWORDS:

• Laser processing
• railway wheel
• laser melt injection
• composite layer
• weldpool
• shape