Improving surface prep productivity with rectangular blasting nozzles / Chang-Hun Lee in JOURNAL OF PROTECTIVE COATINGS & LININGS (JPCL), Vol. 33, N° 5 (05/2016)

[article]  inJOURNAL OF PROTECTIVE COATINGS & LININGS (JPCL) > Vol. 33, N° 5 (05/2016) . - p. 44-46 Titre : Improving surface prep productivity with rectangular blasting nozzles Type de document : texte imprimé Auteurs : Chang-Hun Lee, Auteur ; Byeong-Hun Do, Auteur ; Won-Jun Yun, Auteur ; Han-Jin Bae, Auteur Année de publication : 2016 Article en page(s) : p. 44-46 Langues : Américain (ame) Catégories : Buse (tuyère) Métaux -- Surfaces Traitement de surface par impact -- Appareils et matériels Index. décimale : 667.6 Peintures Résumé : The purpose of surface preparation is ultimately to achieve the necessary coating adhesion between steel and the coated film in order to protect the structure adequately for as long as possible. Adhesion is a significant factor regarding the suitability and lifespan of protective coatings in corrosive environments. In the shipbuilding industry, abrasive blasting is a common method of generating proper surface roughness and achieving high productivity'. Round nozzles are commonly used in abrasive blasting. This article describes a study focused on the use of rectangular nozzles to achieve increased surface preparation productivity by avoiding concentrations of abrasive material typically seen with round nozzles. Rectangular nozzles can disperse abrasive material more evenly due to their shape. The rectangular nozzle used in this study is made of SKD-11 grade steel and has the same sectional area ratio as the reference rectangular nozzle used. The two nozzle types were compared regarding productivity and quality. Abrasive speed and spreading angle were compared using photos captured by a high-speed camera during Eaboratory scale testing. 1). Surface condition and profile achieved were compared using a microscope and quality of surface roughness in the field was assessed with measuring instruments. Because of the round nozzle end, particles are concentrated in a small surface area. However, by changing the shape of nozzle from round to rectangular, particles can be discharged at a wider width for higher productivity. Also, a Venturi shape inside the nozzle can enhance particle velocity, which is the key element of surface cleanliness. Note de contenu : - Rectangular ventury nozzle - Equipment design and development : Comparison of performance using a high-speed camera - Results and discussion : Comparison of velocity - Comparison of spray width - Comparison of work efficiency - TABLES : Comparison of abrasive velocity of round and rectangular nozzles - 2. Comparison of shooting angle of round and rectangular nozzles - 3. Comparison of surface treatment area between round and rectangular nozzles according to carriage speed Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=26838 [article]

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The effect of surface preparation grades of weld seams on coating performance / Sang-Moon Shin in JOURNAL OF PROTECTIVE COATINGS & LININGS (JPCL), Vol. 35, N° 7 (07/2018)

[article]  inJOURNAL OF PROTECTIVE COATINGS & LININGS (JPCL) > Vol. 35, N° 7 (07/2018) . - p. 44-48 Titre : The effect of surface preparation grades of weld seams on coating performance Type de document : texte imprimé Auteurs : Sang-Moon Shin, Auteur ; Chung-Seo Park, Auteur ; Seung-Gon Choo, Auteur ; Eun-Ha Song, Auteur ; Han-Jin Bae, Auteur Année de publication : 2018 Article en page(s) : p. 44-48 Langues : Américain (ame) Catégories : Anticorrosion Epaisseur -- Mesure Epoxydes Essais de brouillard salin Evaluation visuelle Lignes de soudure Métaux -- Revêtements protecteurs Métaux -- Revêtements:Métaux -- Peinture Métaux -- Surfaces Résistance à la fissuration Traîtements de surface Index. décimale : 667.9 Revêtements et enduits Résumé : According to the international surface preparation standard for welds (ISO 8501-3, "Preparation of steel substrates before application of paints and related products - Visual assessment of surface cleanliness - Part 3 : Preparation grades of welds, edges and other areas with surface imperfections"), the preparation grades before paint application are divided into three levels: P1, P2 and P3 (Fig.a). These grades are described with rough qualitative representations instead of with descriptions of surface treatment methods or mesurable conditions. Because of the ambiguous wording in the standard, there have been a lot of argument about surface preparation grades and abraded condition during construction. In this study, coating thickness, the corrosion resistance and crack tendency of the coated films on the welds were evaluated for the grinding range in five levels from mild to servere. Each ground specimen was blasted to Sa 2.5 and coated with two coats of epoxy paints. The performance of coating on welds with the grades of grinding condition were not significantly different, satisfying the criteria of ISO 12944-5, "Paints and varnishes - Corrosion protection of steel structures by protective paint systems - Part 5 : Protective paint systems" (C5-M medium). After blasting, all ground specimens showed smooth surfaces that did not result in a sharp edge or excessive film thickness. Note de contenu : - Visual inspection of surface treatment on the welding line - Measurement of coating film thickness on the welding line - Corrosion resistance - Crack resistance - Fig. 1 : Cross section of a typical weld bead - Fig. 2 : Configuration of the test specimens: T-bar (top) and weld (bottom) - Fig. 3 : Crack resistance test results (the number of cycles of crack initiation) - Table 1 : Appearance of specimens with five grades of surface preparation - Table 2 : Test coating system - Table 3 : Results of coating film-thickness measurements in µm - Table 4 : Rust creepage from the scribe line after salt-spray exposure for 1,440 Hours Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=31888 [article]

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