Influence of low temperature heat treatment on selected properties of hot-dip zinc coating
Instytut Badan i Rozwoju Motoryzacji BOSMAL Sp. z o.o., ul. Sarni Stok 93, 43-300 Bielsko-Biała
Wydział Budowy Maszyn i Informatyki, Akademia Techniczno-Humanistyczna, ul. Willowa 2, 43-309 Bielsko-Biała
This paper contains a continuation of research on the heat treatment (OC) of a hot-dip zinc coating applied to steel and cast iron. This treatment causes changes in the structure of the coating, which directly influences its mechanical and functional properties. In previous publications, the influence of OC in the range of 390 ÅÄ 530.C was analyzed. The above-mentioned treatment resulted in a significant increase in the hardness of the zinc coating, but it was also associated with an adverse effect – a significant reduction in corrosion resistance compared to the base samples . The decrease in corrosion resistance is the result of discontinuities in the coating resulting from treatment at too high temperature. Machining at lower temperatures, i.e. 270-350.C, does not cause such a significant reduction in corrosion resistance, verified by accelerated corrosion tests in a salt chamber according to ISO 9227 (NSS Test). In addition to corrosion resistance, the impact of OC on other properties of the zinc coating, i.e. abrasion resistance using the T-11 tester and analysis of hardness changes, carried out using the Vickers -HV 0.02 method, dedicated to thin coatings. The tests proved the beneficial effect of the low-temperature heat treatment carried out in relation to the obtained values of the tested mechanical properties of the zinc coating.
Keywords: hot-dip zinc coating, corrosion resistance, micro-Vickers hardness, heat treatment
2020, Vol. 63, No 4, pp. 113-117
How to choose the color of construction to make it durable
Instytut Badawczy Dróg i Mostów, Warszawa
The topcoat not only serves as an anti-corrosion protection, but is also responsible for the aesthetics of the building. Due to the degradation of polymeric materials and pigments under the influence of aggressive factors such as UV radiation, humidity or elevated temperature, it is important to select the coating to the expected exploitation conditions. The following article focuses on discussing the durability of the colour of the topcoat and indicates which colours will allow us to maintain the aesthetics of structure for a longer period of time.
Keywords: PUR topcoat, UV weathering, colour measurement, ΔE00
2020, Vol. 63, No 4, pp. 118-121
CORROSION PROTECTION IN PRACTICE
Protective coatings used in the production of agricultural machinery
Metal-Fach Sp. z o.o., Sokółka
Growing user requirements have forced manufacturers of agricultural equipment to invest large forces and resources in the infrastructure of protective coating departments and in the continuous improvement of qualifications of personnel performing and supervising production. In the article below you can find out about selected surface preparation and corrosion protection techniques used in the Polish agrotechnical industry. The paper presents information: how has the approach and expectations of users and manufacturers changed regarding the subject of corrosion protection, and why some products are designed and manufactured in such a way as to meet the requirements of corrosivity category C5 according to the requirements of ISO 12944.
2020, Vol. 63, No 4, pp. 122-125