Electrolytic hard chrome (EHC) coatings have traditionally been utilized for their durability, wear, and corrosion resistance across industries such as aerospace, automotive, and offshore applications. However, rising environmental regulations and health concerns regarding hexavalent chromium, a toxic byproduct of the EHC process, have escalated interest in alternative coating methods. In recent years, technologies such as High Velocity Oxygen Fuel (HVOF), High Velocity Air Fuel (HVAF) have emerged as viable replacements for EHC, offering environmentally friendly and high-performing alternatives. The paper presents the research results on the fabrication of WC-12Co carbide coatings by HVOF which was used to improve the quality of the internal surface pipes operating in aggressive environments. The pipe material used is CT38 steel pipe. The investigated coating properties include porosity, microhardness, adhesion to steel substrates, phase composition. There are three coating technology parameters that have been surveyed, including: relative spray gun speed, spray distance and powder flow. A dedicated internal diameter HVOF system is presented here and specially designed fixtures with a minimum inside diameter of 400 mm have been manufactured for this purpose, with a possibility to spray samples at increasing lengths up to 600 mm. Coating properties are discussed for further optimization of coating performance.