SSPC SP 8-1982 Pickling《酸洗 编辑修订2004年11月1日》.pdf

1、SSPC-SP 8November 1, 1982Editorial Revisions November 1, 20042-79SSPC: The Society for Protective CoatingsSURFACE PREPARATION SPECIFICATION NO. 8Pickling1. Scope1.1 This specication covers the requirements for the pickling of steel surfaces.2. Denition2.1 Pickling is a method of preparing steel surf

2、aces by chemical reaction, electrolysis, or both. The surfaces when viewed without magnication shall be free of all visible mill scale and rust.3. Appearance of the Completed Surface3.1 The surface shall be etched to a degree suitable for the specied painting system.3.2 Uniformity of color may be af

3、fected by the grade, origi-nal surface condition, and conguration of the material being cleaned, as well as by discolorations from mill or fabrication marks, and the shadowing from etching patterns.3.3 Visual standards of surface preparation agreed upon by the contracting parties may be used to furt

4、her dene the surface.4. Referenced Standards4.1 The latest issue, revision, or amendment of the refer-enced standards in effect on the date of invitation to bid shall govern, unless otherwise specied. 4.2 If there is a conict between the requirements of any of the cited referenced standards and this

5、 specication, the requirements of this specication shall prevail.4.3 SSPC AND JOINT SPECIFICATIONS:SP 1 Solvent CleaningSP 2 Hand Tool CleaningSP 3 Power Tool CleaningSP 6/NACE No. 3 Commercial Blast CleaningSP 7/NACE No. 4 Brush-Off Blast CleaningSP 11 Power Tool Cleaning to Bare MetalSP 14/NACE No

6、. 8 Industrial Blast Cleaning5. Pickling Methods and Operation5.1 BEFORE PICKLING, PERFORM THE FOLLOWING:5.1.1 Remove heavy deposits of oil, grease, soil, drawing compounds, and foreign matter other than rust, scale, or oxide by any of the methods specied in SSPC-SP 1. Small quantities of such forei

7、gn matter may be removed in the pickling tanks provided no detrimental residue remains on the surface.5.1.2 Remove heavy deposits of rust, rust scale, and all paint by any one of the methods specied in SSPC-SP 2, SP 3, SP 6, SP 7, SP 14, or SP 11. Rust deposits which can be removed without unduly pr

8、olonging the pickling time may be removed in the pickling tanks.5.2 REMOVE ALL MILL SCALE AND RUST BY ANY OF THE FOLLOWING PICKLING METHODS:5.2.1 Pickling in hot or cold solutions of sulfuric, hydrochloric (muriatic), or phosphoric acid to which sufcient inhibitor has been added to minimize attack o

9、n the base metal, followed by adequate rinsing in hot water above 140 F (60C).5.2.2 Pickling in 5%-10% (by weight) sulfuric acid, con-taining an inhibitor, at a minimum of 140F (60C) until all rust and scale is removed; then thorough rinsing in clean water, then immersion for one to ve minutes in 1%

10、-2% (by weight) phosphoric acid containing about 0.3%-0.5% iron phosphate, at a temperature of about 180F (82C).5.2.3 Pickling in 5% (by volume) sulfuric acid at 170-180F (77-82C), with sufcient inhibitor added to minimize attack on the base metal, until all rust and scale is removed, followed by a

11、two minute rinse in hot water at 170-180F (77-82C). Next, immerse the pickled and rinsed steel for at least two minutes in a hot, inhibitive solution maintained above 190F (88C) and containing about 0.75% sodium dichromate and about 0.5% orthophosphoric acid.5.2.4 Electrolytic pickling in an acid or

12、 an alkaline bath using alternating or direct current. If (when using direct current) the work-piece is made the cathode, hydrogen embrittlement must be prevented or minimized by adequate treatment. If carried out in an alkaline bath, the electrolytic pickling must be followed by a thorough rinse in

13、 hot water; then followed by a dip in a dilute solution of phosphoric acid, or chromic acid, or SSPC-SP 8November 1, 1982Editorial Revisions November 1, 20042-80solution of dichromate until no trace of alkali remains on the surface.5.2.5 “Hydride” descaling, pickling in baths of acid salts, pickling

14、 in baths of molten salts, or pickling in any other man-ner than outlined in the preceding sections shall be permitted only when specied, since their details are beyond the scope of this specication.5.3 Do not exceed a dissolved iron content of 6% in sulfuric acid baths, or 10% in hydrochloric (muri

15、atic) acid baths.5.4 Use only clean water or steam condensate for solutions and rinses. Supply rinse tanks continuously with new water. Do not permit the total amount of acid or dissolved salts due to carry-over to exceed two grams per liter (0.2% by weight).5.5 To minimize carry-over, suspend all s

16、teel briey over the acid tank from which it has been withdrawn and permit the major portion of the acid to drain.5.6 Remove deleterious smut, unreacted acid or alkali, metal deposits, or other contaminants.5.7 Do not stack pickled steel surfaces in contact with one another until completely dry.5.8 A

17、pply paint before visible rusting occurs.6. Inspection6.1 Unless otherwise specied in the procurement docu-ments, the contractor or material supplier is responsible for quality control to assure that the requirements of this document are met. Work and materials supplied under this standard are also

18、subject to inspection by the purchaser or an authorized representative. Materials and work areas shall be accessible to the inspector 6.2 Conditions not complying with this standard shall be corrected. In the case of a dispute, an arbitration or settlement procedure established in the procurement do

19、cuments (project specication) shall be followed. If no arbitration or settlement procedure is established, then a procedure mutually agree-able to purchaser and material supplier (or contractor) shall be used.7. Disclaimer 7.1 While every precaution is taken to ensure that all information furnished

20、in SSPC standards and specications is as accurate, complete, and useful as possible, SSPC cannot assume responsibility nor incur any obligation resulting from the use of any materials, coatings, or methods specied herein, or of the specication or standard itself.7.2 This specication does not attempt

21、 to address problems concerning safety associated with its use. The user of this specication, as well as the user of all products or practices described herein, is responsible for instituting appropriate health and safety practices and for ensuring compliance with all governmental regulations.8. Not

22、esNotes are not requirements of this specication.8.1 A Commentary Section is available and contains ad-ditional information and data relevant to this specication. The Surface Preparation Commentary, SSPC-SP COM, is not part of this specication. The table below lists the subjects discussed relevant to pickling and appropriate Commentary Section.Subject Commentary SectionFilm Thickness 10Inhibitors .8.4Rust Back .4.5Weld Spatter 4.4.1Visual Standards .11