【導(dǎo)讀】PSH3022?1999. 1999?09?22issure2020?01?01enforcement. 版為準(zhǔn)。coating.furtherrevision.4. 4. 5. 5. 8. 9. 11. 13. 13. 14. 17. 21

　　

【正文】 rvation. Coating ought to be plete, uniform, coating courses and thickness should meet design requirements. Technical targets of anticorrosion coating in mon use for equipment and piping should meet stipulation in Appendix D of this Specification. Surface treatment and inspection Before surface treating, determine rusting grade according to item in this Specification. Surface rustremoving grade can be practiced according to requirement of and — 15 — in this Specification. The following methods can be used for rustremoving: ⑴ dry injection: suitably use quartz sand as abrasive material with clean and dry pressed air of to not wet metal surface to be injected. When metal surface temperature is 3℃ lower than dew point, injecting operation should stop. ⑵ hand tool rustremoving: use scaling hammer and other tools to remove thick rust and spatter, then use metal brush perching knife and other tool brush to scrape or polish in order to remove loosen oxide skin, rust and aged coating on metal surface. ⑶ power tool rustremoving: use power driven rotary or impact rustremoving tool, such as rotary metal brush, and remove loosen oxide skin, rust and aged coating. When using impact tool to remove rust, do not damage metal surface。 when using rotary tool to remove rust, too smooth scraping metal surface is unsuitable. For location which power tool can not reach on metal surface, need supplemental treatment of cleaning wich hand. Before rustremoving, surface contaminated by grease can use one of the methods listed in Table to remove oily pollutant, after that, use water or steam to wash it. For aged surface coating, can use the following methods to remove: ⑴ mechanical method: ⑵ burning method : when used for thinwall equipment, should take measures to prevent shell from deformation, but this burning method is not suitable for annealed steel, quenched steel or heattreated equipment and piping. ⑶ dissolution method of hot alkali liquor: When using this method, measures discharging residual liquid are needed, this kind of method is not suitable f alkaliresistant coating. Table Greasy dirtremoving method of surface method Cleaning solution (mass %) Cleaning solution Temperature (℃ ) Cleaning time (min) applicability Solvent method 200 solvent oil kerosene Normal temperature Until washing out Ordinary greasy dirt Alkali washing method Sodium hydroxide 3 Tertiary sodium phosphate 5 Sodium silicate 3 Water 89 90 40 Containing small amount of greasy dirt Sodium hydroxide 5 Sodium carbonate 10 Sodium silicate 10 Water 75 90 40 Containing large amount of greasy dirt — 16 — ⑷ paintremoving method: when using this method, it is necessary to take measures to discharge residual liquid and protect operator’s skin. After finishing removing paint, use gasoline to wash and scour, now, can start coating. After finishing surface treatment, should carry out gross inspection and local sampling inspection in accordance with the following specification: ⑴ gross inspection means mainly inspecting surface to be rustremoved whether having missing moving part(rust, greasy dirty) or not, and caring about rustremoving quality at corner part as well as cleaning of surface greasy dirt and dust. ⑵ Local sampling inspection means contrasting rustremoved surface with typical sample photograph stipulated by item of this Specification, and meeting the following requirements: a. Inspect equipment one by one including five places for each, and the inspected area not less 100 cm2. b. Inspect piping according to total extension meter of identical pipe diameter and rustremoving grade. For length less than or equal to 500m, sample five points。 for more than 500m, increase one sampling point per 100m, each inspected area should not to be less than 100cm2. c. Inspect accessory steel structure according to category. For some steel structure, sample five points to check, the area of each is 50100cm2. In inspection of surface treatment, if find points not conforming to rustremoving grade requirements, should retreat them again until being acceptable. Table Check list of surface treatment (format) Project name/unit name Treated object name Total working capacity(m2) Rust grade Rustremoving grade Inspection item Inspection result Inspection suggestion Gross inspection Missing rustremoving Corner or local rustremoving Greasy oil and dust cleaning Local sampling Complex quality evaluation Quality inspector Technical personnel in charge Inspection date — 17 — After finishing surface treatment, ought to fill in inspection result form, as a format, presented in Table . After finishing steel surface handling, should use up priming coat within 4 hours. When find new rust, ought to retreat surface again. For equipment, piping and other accessory steel structure which are needed processing in fabricating yard, should perform surface treatment and coat primer before installation. Anticorrosion construction for onground equipment Before coating primer, should protect some special places such as assembling sign, welding groove, thread, and prevent them from sticking coat. Keep coating surface dry. Wait until previous course of paint dried, then can use the following course of paint (except vinyl perchloride paint, polyurethane paint).The method of judging paint film whether is real dry or not depends on forcefully pressing film with fingers without producing any finger print.. Construction of coating suitably use spread coating, roller coating or spray coating, and it should meet the following specification: ⑴ When spread and roller coating being carried out, interlayer should be