ISO 8074:2025
(Main)Aerospace — Surface treatment of austenitic stainless steel parts
Aerospace — Surface treatment of austenitic stainless steel parts
This document specifies the requirements for technical procedures, quality inspection, etc. for the surface treatment of austenitic stainless steel parts (e.g. 300 series, AISI 651, A286 or equivalent). This document applies to the removal of organic and inorganic contaminants, surface cleaning, surface finishing and surface passivation before the non-destructive test of austenitic stainless steel parts.
Aéronautique et espace — Traitement de surface des éléments en acier inoxydable austénitique
General Information
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Standards Content (Sample)
International
Standard
ISO 8074
Second edition
Aerospace — Surface treatment of
2025-05
austenitic stainless steel parts
Aéronautique et espace — Traitement de surface des éléments en
acier inoxydable austénitique
Reference number
© ISO 2025
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Contents Page
Foreword .iv
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 Technical requirements . 2
4.1 General .2
4.2 Technical requirements .2
4.3 Process details .3
4.3.1 Degreasing cleaning .3
4.3.2 Removal of scale and oxides .3
4.3.3 Etching prior to penetrant inspection .5
4.3.4 Smoothing surface .6
4.3.5 Passivation .7
4.3.6 Rinse and dry .8
4.3.7 Rework .8
5 Quality control . 8
5.1 Responsibility for inspection.8
5.2 Batch acceptance tests .8
5.2.1 Appearance .8
5.2.2 Corrosion resistance .8
5.3 Process control tests .8
5.4 Process qualification tests .9
5.5 Solution control . .9
5.6 Inspection and test .9
5.6.1 Appearance .9
5.6.2 Corrosion resistance .10
5.7 Approval .10
6 Packaging and delivery .11
6.1 Packaging .11
6.2 Delivery .11
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Foreword
ISO (the International Organization for Standardization) is a worldwide federation of national standards
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in the ISO/IEC Directives, Part 1. In particular, the different approval criteria needed for the different types
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This document was prepared by Technical Committee ISO/TC 20, Aircraft and space vehicles, Subcommittee
SC 18, Materials.
This second edition cancels and replaces the first edition (ISO 8074:1985) which has been technically revised.
The main changes are as follows:
— added the normative references in Clause 2;
— added rinse and dry (see 4.3.6);
— added rework (see 4.3.7);
— made the requirements of process control tests and process qualification tests clearer (see 5.3 and 5.4).
Any feedback or questions on this document should be directed to the user’s national standards body. A
complete listing of these bodies can be found at www.iso.org/members.html.
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International Standard ISO 8074:2025(en)
Aerospace — Surface treatment of austenitic stainless steel parts
1 Scope
This document specifies the requirements for technical procedures, quality inspection, etc. for the surface
treatment of austenitic stainless steel parts (e.g. 300 series, AISI 651, A286 or equivalent).
This document applies to the removal of organic and inorganic contaminants, surface cleaning, surface
finishing and surface passivation before the non-destructive test of austenitic stainless steel parts.
2 Normative references
The following documents are referred to in the text in such a way that some or all of their content constitutes
requirements 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 9227, Corrosion tests in artificial atmospheres — Salt spray tests
3 Terms and definitions
For the purposes of this document, the following terms and definitions apply.
ISO and IEC maintain terminology databases for use in standardization at the following addresses:
— ISO Online browsing platform: available at https:// www .iso .org/ obp
— IEC Electropedia: available at https:// www .electropedia .org/
3.1
batch
parts processed in the same passivation tank and within the same time period
3.2
water-break-free
surface that maintains a continuous water film for a period of at least 30 s after having been sprayed or
immersion-rinsed in clean water at a temperature below 38 °C
3.3
room temperature
ambient temperature of the production site
Note 1 to entry: The room temperature for the surface treatment of the parts should be controlled at 12 °C to 38 °C.
3.4
sensitized state
state of austenitic stainless steel after being heated in the temperature range of 450 °C to 950 °C, when it is
easy to precipitate high chromium carbide between grains, reducing the chromium content near the grain
boundary, thus reducing the corrosion resistance
4 Technical requirements
4.1 General
4.1.1 Before any heat treatment (e.g. annealing, welding) required in the manufacturing process, all
surfaces of the part shall be treated in accordance with one or more of the following:
a) degreasing and cleaning of organic pollutants and other carbide pollutants shall be in accordance with 4.3.1;
b) contaminants such as oxides, scales, and discolorations shall be treated in accordance with 4.3.2;
c) metal contamination (other than sheet parts for shearing and hole-making only, or heat treatment
temperatures below 650 °C) shall be passivated in accordance with 4.3.3.
4.1.2 Before finishing and passivation, the parts should have completed all processing operations (such as
forming, machining, heat treatment, welding), and the surface should be clean and free from pits, scratches
and mechanical damage.
4.1.3 A final surface passivation shall be carried out, except when a surface coating is specified
(e.g. painting, electroplating).
4.1.4 When a coating is specified as only part of the surface of the part, the part without coating shall be
passivated in accordance with the requirements of 4.3.
4.1.5 The stainless steels involved in this document are non-magnetic; and the non-destructive test
should include a penetrant inspection. Before the penetrant inspection, degreasing cleaning or descaling
treatment should be carried out and the metal layer that can affect the inspection results should be removed
by pickling. If the layer is smeared, at least 5 μm of the surface should be removed.
4.1.6 It is the responsibility of the operator to determine, based on analysis or history, that the condition
of the surface prior to treatment conforms to the requirements of this document.
4.2 Technical requirements
4.2.1 The process shall meet the requirements of this document.
4.2.2 The process shall be subject to an appropriate solution control by recognized methods of chemical
analysis.
4.2.3 Suppliers of proprietary chemicals shall provide processors with analytical methods and instructions
for solution maintenance in writing.
4.2.4 The total dissolved solids in the water for the make-up solution and the final rinse water after
passivation treatment shall not exceed 100 mg/kg; The chloride ion content shall not exceed 12 mg/kg,
respectively; The pH range should be 5,5 to 8,0. After degreasing and pickling treatments, the part can be
rinsed with tap water.
4.2
...
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