BS ISO 14952-4-2004 Space systems - Surface cleanliness of fluid systems - Rough-cleaning processes《航天系统 液体系统的表面清洁度 粗略清洁过程》.pdf

1、BRITISH STANDARD AEROSPACE SERIES BS ISO 14952-4:2003 Space systems Surface cleanliness of fluid systems Part 4: Rough-cleaning processes ICS 49.080; 49.140 BS ISO 14952-4:2003 This British Standard was published under the authority of the Standards Policy and Strategy Committee on 2 March 2004 BSI

2、2 March 2004 ISBN 0 580 43465 6 National foreword This British Standard reproduces verbatim ISO 14952-4:2003 and implements it as the UK national standard. The UK participation in its preparation was entrusted to Technical Committee ACE/68, Space systems and operations, which has the responsibility

3、to: A list of organizations represented on this committee can be obtained on request to its secretary. Cross-references The British Standards which implement international publications referred to in this document may be found in the BSI Catalogue under the section entitled “International Standards

4、Correspondence Index”, or by using the “Search” facility of the BSI Electronic Catalogue or of British Standards Online. This publication does not purport to include all the necessary provisions of a contract. Users are responsible for its correct application. Compliance with a British Standard does

5、 not of itself confer immunity from legal obligations. aid enquirers to understand the text; present to the responsible international/European committee any enquiries on the interpretation, or proposals for change, and keep the UK interests informed; monitor related international and European develo

6、pments and promulgate them in the UK. Summary of pages This document comprises a front cover, an inside front cover, the ISO title page, pages ii to iv, pages 1 to 4, an inside back cover and a back cover. The BSI copyright notice displayed in this document indicates when the document was last issue

7、d. Amendments issued since publication Amd. No. Date Comments Reference number ISO 14952-4:2003(E) OSI 3002INTERNATIONAL STANDARD ISO 14952-4 First edition 2003-11-15 Space systems Surface cleanliness of fluid systems Part 4: Rough-cleaning processes Systmes spatiaux Propret des surfaces en contact

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13、:2003IS-25941 O4:(3002E) I SO 3002 All irhgts seredevr iiiForeword ISO (the International Organization for Standardization) is a worldwide federation of national standards bodies (ISO member bodies). The work of preparing International Standards is normally carried out through ISO technical committe

14、es. Each member body interested in a subject for which a technical committee has been established has the right to be represented on that committee. International organizations, governmental and non-governmental, in liaison with ISO, also take part in the work. ISO collaborates closely with the Inte

15、rnational Electrotechnical Commission (IEC) on all matters of electrotechnical standardization. International Standards are drafted in accordance with the rules given in the ISO/IEC Directives, Part 2. The main task of technical committees is to prepare International Standards. Draft International S

16、tandards adopted by the technical committees are circulated to the member bodies for voting. Publication as an International Standard requires approval by at least 75 % of the member bodies casting a vote. Attention is drawn to the possibility that some of the elements of this document may be the su

17、bject of patent rights. ISO shall not be held responsible for identifying any or all such patent rights. ISO 14952-4 was prepared by Technical Committee ISO/TC 20, Aircraft and space vehicles, Subcommittee SC 14, Space systems and operations. ISO 14952 consists of the following parts, under the gene

18、ral title Space systems Surface cleanliness of fluid systems: Part 1: Vocabulary Part 2: Cleanliness levels Part 3: Analytical procedures for the determination of nonvolatile residues and particulate contamination Part 4: Rough-cleaning processes Part 5: Drying processes Part 6: Precision-cleaning p

19、rocesses BSISO149524:2003IS-25941 O4:(3002E) iv I SO 3002 All irhgts seredevrIntroduction This part of ISO 14952 defines rough-cleaning processes intended for use prior to precision-cleaning processes for equipment and components used in space fluid systems. The purpose of this part of ISO 14952 is

20、to provide processes that can be used to achieve visibly clean parts and components. BSISO149524:2003INTENRATIONAL TSANDADR IS-25941 O4:(3002E)I SO 3002 All irhgts seredevr 1Space systems Surface cleanliness of fluid systems Part 4: Rough-cleaning processes 1 Scope This part of ISO 14952 provides re

21、quirements related to rough-cleaning processes used to prepare parts and components for precision cleaning. It identifies precleaning processes that can be used for ground support equipment, launch vehicles and spacecraft. Rough cleaning removes contaminants such as weld scale, heat-treat scale, cor

22、rosion, oxide films, oils, grease, shop soil, fuel and carbon deposits. Rough cleaning is considered a normal shop process and usually does not require special environmental controls, packaging, handling or storage beyond accepted good practice. This part of ISO 14952 is applicable equally to ground

23、 support equipment, launch vehicles and spacecraft. NOTE The cleanliness level achieved by rough cleaning does not normally require verification beyond visual inspection. (Wipe test, waterbreak test, ultraviolet inspection, special lights and mirrors are considered aids to visual inspection.) 2 Norm

24、ative references The following referenced documents are indispensable for the application of this document. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies. ISO 14951-10:1999, Space systems

25、 Fluid characteristics Part 10: Water ISO 14952-1:2003, Space systems Surface cleanliness of fluid systems Part 1: Vocabulary 3 Terms and definitions For the purposes of this document, the terms and definitions given in ISO 14952-1 apply. 4 Rough-cleaning requirements 4.1 General All parts, componen

26、ts, assemblies, systems or related equipment for use in ground support facilities, launch vehicles and spacecraft shall be cleaned and inspected. Assembled parts that may be damaged during the cleaning process shall be disassembled to a level to permit cleaning. The design for systems and system com

27、ponents should, where practical, include the capability to remove all valves and components from the system. BSISO149524:2003IS-25941 O4:(3002E) 2 I SO 3002 All irhgts seredevr4.2 Rough cleaning All critical surfaces of system hardware shall be rough cleaned to remove dirt, grit, scale, corrosion, g

28、rease, oil and other foreign matter prior to any precision-cleaning process. Metallic items shall be surface treated (cleaned, passivated and/or coated), as applicable, to prevent latent corrosion and contamination. Assembled items that do not lend themselves to this type of treatment shall be treat

29、ed prior to assembly. Surface areas degraded during subsequent fabrication and assembly shall be reprocessed, as required, to restore the original protective finish. 4.3 Material selection 4.3.1 General The selection of the materials used in processing shall be left to the discretion of the customer

30、. However, the fluids shall be compatible with the item being cleaned. The following compatibility issues, as applicable, shall be considered and evaluated in the selection of processing procedures and materials: a) corrosion; b) stress corrosion cracking; c) embrittlement; d) leaching; e) masking o

31、f crack-like indications; f) residue; g) crazing (nonmetallics); h) reversion (nonmetallics); i) hydrolysis (nonmetallics). 4.4 Types of rough cleaning 4.4.1 General The actual choice of the specific cleaning agents shall be determined by the cleaning contractor and the customer. Descriptions of the

32、 cleaning agents, their purpose and application are provided in 4.4.2 to 4.4.8. The use of ultrasonics has been found to enhance the cleaning efficiency of the first five processes described. Care should be taken in the selection of the frequency of the ultrasonic bath. Lower frequencies have been f

33、ound to be the most efficient in the removal of contamination; however, frequencies below 25 kHz have been found to damage soft metals such as aluminium and silver. Chemical cleaning agents shall be compatible with material composition to prevent excessive attack or latent degradation. 4.4.2 Acid cl

34、eaners Acid cleaners are used to remove the contamination (e.g. weld scale, corrosion and oxide films not removable by other solutions). Acid cleaners include nitric acid, chromic acid inhibited hydrochloric acid, inhibited sulfuric acid, inhibited phosphoric acid, mixed acid deoxidizers and alcohol

35、ic phosphoric acid. BSISO149524:2003IS-25941 O4:(3002E) I SO 3002 All irhgts seredevr 34.4.3 Alkaline cleaners Alkaline cleaners are used for the removal of organic and inorganic contamination (e.g. grease, shop soil, scale and soluble metal oxides). Alkaline cleaners dissolve (etch) certain metals

36、such as aluminium or zinc. Types of alkaline cleaners include alkaline rust strippers, heavy-duty alkaline cleaners, molten alkalines, alkalis and alkalis with nitrates or phosphates. 4.4.4 Degreasers (organic and aqueous-based solvents) Degreasers are used to remove some forms of organic contaminat

37、ion (e.g. oils, grease and hydrocarbon fuels). 4.4.5 Mild alkaline cleaners and detergents Mild alkaline cleaners and detergents are used for the removal of organic and inorganic contamination (e.g. oils, fats, shop soil and grease). Mild alkaline cleaners and detergents include inhibited alkaline c

38、leaners (mild alkaline cleaners), soaps and detergents. 4.4.6 Tap water and high-purity water (HP) Tap water or high-purity water used to remove the residual material left by cleaning solutions and reagent water, in accordance with ISO 14951-10, Type HP, shall be used as a final flushing or rinsing

39、medium. 4.4.7 Neutralizing and passivating solutions Neutralizing and passivating solutions shall be used as a supplementary treatment to acid, alkaline and mechanical cleaning. The neutralizing and passivating solutions prevent corrosion and acid etching. Nitrates, and alkalis with nitrates or phos

40、phates shall be used for neutralization; nitric acid solutions shall be used for passivation. 4.4.8 Mechanical cleaning Mechanical cleaning removes contamination by abrasive action. It is used only when physical damage to the item being cleaned will not occur. Mechanical cleaning includes wire brush

41、ing, shot blasting (wet and dry), grinding, abrasive blasting (wet or dry), the use of aluminium oxide, abrasive-coated papers and cloths, and related methods. NOTE Mechanical cleaning often leaves foreign deposits that may require additional cleaning removal. Compatibility of dissimilar metals is a

42、n important consideration when selecting a mechanical cleaning method. 4.5 Rough-cleaning processes Table 1 shows recommended rough-cleaning processes. BSISO149524:2003IS-25941 O4:(3002E) 4 I SO 3002 All irhgts seredevrTable 1 Selection chart for rough-cleaning processes Material Surface condition M

43、echanical descale/clean 1 Degrease Alkaline clean Tap water rinse Detergent clean 1 Tap water rinse Acid pickle Tap water rinse Passivate Tap water rinse 1 High-purity water 1 Drying Bare or machined free of heat oxidation X X X X X Conversion or chemical film coating X X X X X Aluminium Weld scale,

44、 corrosion, or heat oxidation X X X X X X Bare or machined free of heat oxidation X X X X X Conversion or chemical film coating X X X X X X X Copper, brass, bronze Weld scale, corro- sion, or heat oxidation X X X X X X X Free of scale X X X X X X X X X Stainless steel Weld scale, corrosion, or heat

45、oxidation X X X X X X X X X X Free of scale X X X X X X Carbon steel Weld scale, corrosion, or heat oxidation X X X X X X X X X Bare or machined X X aX X X X X X Titanium Conversion or chemical film coating X X X X X X X Nonmetallic parts As received X X X X Electroplated parts and dissimilar metals

46、 As received X X X X X NOTE Symbols in the block denote a recommended process for the surface condition indicated, and steps will normally be accomplished in consecutive order from left to right.aDo not use halogenated solvents. BSISO149524:2003blankBS ISO 14952-4:2003 BSI 389 Chiswick High Road Lon

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