EFFECT OF TIG HARDFACING PROCESS PARAMETERS ON THE STRUCTURAL CHARACTERISTICS OF SHUT-OFF VALVE COMPONENTS

Abstract

The study presents an experimental investigation of the influence of GTAW/TIG cladding process parameters on the formation of microstructure and the dilution coefficient of the deposited layer on valve seats made of low-carbon alloy steel. The cladding was performed using 6M filler wire while varying the welding current (90–150 A), preheating temperature (150–200 °C), travel speed, and other technological parameters. Metallographic analysis of the deposited layer and the heat-affected zone was carried out, and the dilution coefficient was calculated.

It was established that increasing the welding current and preheating temperature leads to an increase in the dilution coefficient up to 22%, accompanied by the formation of a directional columnar dendritic structure. With a further increase in heat input, a decrease in the dilution coefficient is observed due to the redistribution of heat flows. Under the studied conditions, the optimal режим is recommended at a welding current of 140 A and a preheating temperature of 180 °C, providing a favorable combination of structural uniformity and process stability.

The obtained results can be used in the development of технологические regulations for cladding of valve seats in order to improve their durability and operational reliability.