Use of GDOES method for evaluation of the quality and thickness of hot dip galvanised coating

ABSTRACT

The paper describes an assessment of thickness and quality of hot-dip galvanised coating by means of the glow discharge optical emission spectrometry method (GDOES). For comparison, a metallographic analysis was made using an optical microscope. An important factor influencing thickness and quality of the hot-dip galvanised coating is chemical composition of steel, particularly the amounts of silicon. Structural steels with a low amount of silicon S235JR and S355J2 were chosen for the experiment and high-strength steel S690QL with a high amount of silicon was chosen for comparative purposes. The results of the coating thickness measurement by means of GDOES and optical microscopy show only minimal differences. Steel S690QL shows a thick and uneven zinc coating. In the case of steels S235JR and S355J2 an optimal hot-dip galvanised coating was observed.

KEYWORDS:

• Zinc coating
• GDOES
• optical microscopy
• hot dip galvanising
• thickness

Additional information

Funding

This work was supported by the project no. LO1203 ‘Regional Materials Science and Technology Centre – Feasibility Program’ funded by Ministry of Education, Youth and Sports of the Czech Republic and SP2018/60 ‘Specific research in metallurgical, materials and process engineering’.