Page 1 of 10
GS 97121-1:2022-06
BMW Group Standard Released GS 97121-1
2022-06
Replacement for
GS 97121-1:2022-02
Inorganic surface coatings
Anodized aluminum parts for motorbikes
Requirements and tests
Edited by
Ricarda Meier, Standardization
Print-outs are not subject to the change service.
The user of this document is under obligation to verify its current validity.
Continued page 2 to 10
© BMW Group – All rights reserved
Page 2 of 10
GS 97121-1:2022-06
Contents
1 Scope and purpose .................................................................................................................................................3
2 Normative references .............................................................................................................................................3
3 Abbreviations, symbols and terms .......................................................................................................................3
3.1 Abbreviations ..........................................................................................................................................................3
3.2 Symbols ....................................................................................................................................................................3
3.3 Terms........................................................................................................................................................................3
4 Designation ..............................................................................................................................................................3
5 General .....................................................................................................................................................................4
5.1 Finishes ....................................................................................................................................................................4
5.2 Drawing entry ..........................................................................................................................................................4
5.3 Application purpose ................................................................................................................................................4
5.4 Base material ..........................................................................................................................................................4
5.5 Rework .....................................................................................................................................................................4
5.6 Frictional behavior of threads ...............................................................................................................................4
6 Requirements and tests .........................................................................................................................................5
6.1 General rules............................................................................................................................................................5
6.2 Test cause ................................................................................................................................................................6
6.3 Tests .........................................................................................................................................................................7
6.4 Requirements ..........................................................................................................................................................9
Foreword
The German version is binding.
The reproduction, distribution and utilization of this document as well as the communication of its contents to others
without express authorization is prohibited. Offenders will be held liable for the payment of damages. All rights
reserved.
This Group Standard has been coordinated with the responsible departments of the BMW Group. The names of the
persons creating, releasing and checking this Group Standard are filed and can be retrieved in the master data of
the TEREG system.
Amendments
The following amendments have been made to GS 97121-1:2022-02:
− section 5.1: finishes changed;
− section 5.2 updated.
Previous editions
2022-02
Page 3 of 10
GS 97121-1:2022-06
1 Scope and purpose
This Group Standard specifies the requirements and tests for anodized coatings for decorative applications at the
exterior of motorbikes.
The Group Standard aims at the continuous compliance with quality characteristics in terms of appearance and
haptics over the entire service life and at all operating conditions.
2 Normative references
This Group Standard incorporates provisions from other publications. These normative references are cited at the
appropriate places in the text and the publications are listed hereafter. The respective latest edition of the
publication is applicable.
AA-0026 Aging resistance test
AA-0055 Chemical resistance test of surfaces
AA-0079 Determination of multi impact stone chip resistance
AA-0213 Condensation water constant atmosphere test
AA-0235 Accelerated weathering crack stability
AA-0324 Saltspray-Test
DIN 17611 Anodized products of wrought aluminium and wrought aluminium alloys; Technical
conditions of delivery
DIN EN ISO 1463 Metallic and oxide coatings; Measurement of coating thickness; Microscopical method
DIN EN ISO 2360 Non-conductive coatings on non-magnetic electrically conductive base metals;
Measurement of coating thickness; Amplitude-sensitive eddy-current method
DIN EN ISO 20567-1 Paints and varnishes; Determination of stone-chip resistance of coatings, Part 1: Multi-
impact testing
GS 90010-1 Types of surface protection for metallic materials; Metallic coatings and inorganic coating
systems; Standard parts and standard-related drawing parts
GS 97107 Surface coatings; Anodized aluminium parts; Requirements, tests
VDA Band 16 Quality Management in the Automotive Industry; Decorative surfaces of accessories and
functional parts in the exterior and interior areas of automobiles
3 Abbreviations, symbols and terms
3.1 Abbreviations
MTP maximum tolerable processing conditions
QMT Parts Quality Management
3.2 Symbols
There are no symbols in this document.
3.3 Terms
There are no terms in this document.
4 Designation
There is no designation in this document.
Page 4 of 10
GS 97121-1:2022-06
5 General
5.1 Finishes
The following finishes exist for decorative surfaces:
− anodized natural;
− anodized black;
− anodized blue;
− anodized grey;
− anodized gold.
NOTE 1 Initial samples are not provided, only reference components.
NOTE 2 For the function build phase MTP samples (definition according to VDA Band 16) shall be created in
coordination with the specialist departments “Purchasing and Supplier Network” and “Group Design”.
5.2 Drawing entry
EXAMPLE Designation of coating of type anodized natural:
Surface anodized according to GS 97121-1 - natural
5.3 Application purpose
This Group Standard applies only to anodized coatings without additional coatings. GS 97107 applies to
components with additional coating.
5.4 Base material
Only anodizable aluminium substrates may be used. For substrates that are not classified as suitable for anodizing
according to DIN 17611, the suitability shall be demonstrated by the supplier in accordance with DIN 17611 before
contract awarding.
Proof of this shall be demonstrated towards specialist department “Materials, Process Technology”. The use of
this substrate shall be coordinated with above specialist department.
5.5 Rework
The only permissible rework method for anodized surfaces is complete de-anodizing and re-coating. Reworked
components shall meet all requirements (including those not specified in this Group Standard) to the full extent.
The reduced wall thickness resulting from rework shall not change the properties of the component.
5.6 Frictional behavior of threads
When anodizing threads, the friction requirements according to GS 90010-1 shall be complied with.
Page 5 of 10
GS 97121-1:2022-06
6 Requirements and tests
6.1 General rules
6.1.1 Scope of testing
The manufacturer shall demonstrate that his delivery fully complies with the requirements of this Group Standard.
The required tests include the climatic, chemical and mechanical resistance of the finished surface. They shall be
performed on real components as supplied to the BMW Group.
Sampling shall be carried out in accordance with the rules of statistical quality control. All samples of an inspection
lot shall fully meet all relevant requirements in order for the test/inspection to be considered passed.
6.1.2 Test report
For each test cause (principle approval, initial sample, reliability), a test report shall be prepared that shall meet the
following requirements:
− master data (by supplier) of the components;
− BMW part number;
− date of manufacture;
− production lot;
− production site of the component;
− production site of coating;
− list of samples;
− results of all required tests for all samples in tabular form;
− documentation of the test position in the respective chamber and of the tested components:
a) overview images of all sides with position of details;
b) detailed images of the corrosion spots that cause the respective rating;
c) image size at least 8 cm x 10 cm in the printout;
d) all images with scale;
Resolution:
e) at least 5 megapixels for image;
f) at least 300 dpi in printout (or .pdf)
Lighting, contrast, magnification and other relevant parameters shall be selected in such a way that the information
to be displayed are clearly visible.
6.1.3 Testing orientation for climatic resistance tests
For all climatic resistance tests, test panels, test sheets as well as real components and assemblies shall be aligned
at an angle of 60° to 75° relative to the surface to be tested. The component side which is subject to a higher
corrosive load, in the position as installed in the vehicle, should point upwards.
Build-up or puddles of test media on the sample are to be avoided. Samples shall not mutually touch or shade each
other or spread test solution to other components.
In individual cases, an alignment other than the above may be used for complex components. This shall be
coordinated with specialist department “Product Sustainability, Corrosion Resistance” however.
Page 6 of 10
GS 97121-1:2022-06
6.2 Test cause
6.2.1 Principle release
It is recommended to perform the principle release of the coating selected for a project/component prior to contract
awarding to the series supplier.
The principle release is an initial release of the planned coating process, including the materials used on sample
sheets or components, whereby the following boundary conditions apply:
− the substrate (including manufacturing process, heat treatment and finish) shall comply with the planned series
specifications;
− the process sequence and all process materials shall correspond to the planning for series production.
This test can be carried out by the respective material supplier, a laboratory recognized by Technology Materials
and Process Analytics or by Technology Materials and Process Analytics itself.
If one of the materials and/or process steps for series coating is subsequently changed, a new basic approval for
the new overall process is required.
6.2.2 Initial sample inspection
The prerequisite for series delivery is the release of initial samples. For this purpose, the supplier shall submit the
initial sample test report in good time, including the initial samples. The date for the initial sample inspection shall
be coordinated with the BMW Group's QMT specialist departments.
Each manufacturing site of a surface treatment of a component requires its own test report. The supplier is
responsible for the initial sample inspection.
The samples from the initial sample test shall be stored for at least one year after the end of the test and presented
to the BMW Group upon request.
The initial sample inspection shall be performed exclusively on components processed in conformance with the
specified series production processes. This applies not only to the coating process but to all upstream and
downstream process steps.
In the case of long logistics chains before ownership is transferred to the BMW Group it shall be agreed which
additional tests are required.
Any process change in one of the sub-processes (e.g. changes in bath chemistry, plant relocation) is subject to
notification to the BMW Group purchasing and quality specialist departments.
A new initial sample inspection is generally required. The scope of the tests and the required samples are
determined by the BMW Group's QMT specialist departments.
If several BMW components are affected, a reduced scope of testing may be carried out on selected components.
6.2.3 Reliability tests
The required reliability tests (series-accompanying tests) are to be taken from the requirements table in section 6.4.
The test can be carried out by the supplier or a commissioned laboratory.
Page 7 of 10
GS 97121-1:2022-06
6.3 Tests
6.3.1 Tests to be performed
The following sections describe the tests and requirements to be performed on the anodized surfaces. The tests
and requirements are identical for all colors, there is no distinction between the finishes described in section 5.1.
6.3.2 Condensation water constant climate test
Execution and evaluation according to AA-0213.
The cross-cut test described in AA-0213 before and after the condensation water constant climate test is not part
of this test.
It is permissible to polish the sample before assessing the surface changes.
6.3.3 Salt spray test
Execution and evaluation according to AA-0324.
6.3.4 Short-term weathering in Xenon test device (crack resistance)
Execution and evaluation according to AA-0235.
The cross-cut test described in AA-0235 is not part of this test.
It is permissible to polish the sample before assessing the surface changes.
6.3.5 Determination of multi impact stone chip resistance
Execution and evaluation according to AA-0079.
6.3.6 Resistance test against service fluids and care products
The resistance test shall be performed with the following service fluids/care products:
− rim cleaner;
− motorbike cleaner;
− engine oil;
− brake fluid;
− fuel.
Execution and evaluation according to AA-0055. The methods to be applied for the respective service fluids/care
products are defined in Table 1.
Only service fluids and care products approved by BMW are permitted.
6.3.7 Alkali resistance pH 12,5
Execution and evaluation according to AA-0055, method 7.
The alkali resistance test described in AA-0055 is not performed for 10 min, as described in method 7. The
requirement here is an immersion time of 5 min at room temperature.
It is permissible to polish the sample before assessing the surface changes.
Page 8 of 10
GS 97121-1:2022-06
6.3.8 Ageing resistance test
Execution and evaluation according to AA-0026.
The adhesion tests after temperature exposure described in AA-0026 are not part of this test. After the
temperature exposure only surface changes shall be assessed.
6.3.9 Coating thickness
The coating thickness is measured in accordance with DIN EN ISO 2360 or DIN EN ISO 1463.
The measuring points for determining the coating thickness are generally defined on the drawing. In exceptional
cases the measuring points shall be agreed separately with the BMW development departments.
The values specified in Table 1 are recommended minimum coating thicknesses. Compliance with the respective
corrosion protection requirement is decisive for the release.
Page 9 of 10
GS 97121-1:2022-06
6.4 Requirements
Table 1: Requirements on anodized coating
Test Test conditions Requirements Test cause
Condensation water constant climate test 240 h Grade 2 - slightly changed G, E, Z
(section 6.3.2) according to AA-0213 according to AA-0055, Table 1
Salt spray test 240 h Grade 1 - changed very slightly G, E, Z
(section 6.3.3) according to AA-0324 according to AA-0055, Table 1
Short-term weathering in Xenon test device (crack 1 500 h Grade 3 - average changed G
resistance)
according to AA-0235 according to AA-0055, Table 1
(section 6.3.4)
Determination of multi impact stone chip Stone chip exposure Grade 2 - damaged area 5,5 % G
resistance
according to AA-0079 according to DIN EN ISO 20567-1,
(section 6.3.5) Figure 3
Resistance test against engine oil Method 2 Grade 2 - slightly changed G
(section 6.3.6) according to AA-0055 according to AA-0055, Table 1
Resistance test against motorbike cleaners Method 2 Grade 2 - slightly changed G
(section 6.3.6) according to AA-0055 according to AA-0055, Table 1
Resistance test against rim cleaners Method 2 Grade 2 - slightly changed G
(section 6.3.6) according to AA-0055 according to AA-0055, Table 1
Resistance test against brake fluid Method 2 Grade 3 - average changed G
(section 6.3.6) according to AA-0055 according to AA-0055, Table 1
Resistance test against fuels Method 1 Grade 1 - changed very slightly G
(section 6.3.6) according to AA-0055 according to AA-0055, Table 1
Page 10 of 10
GS 97121-1:2022-06
Test Test conditions Requirements Test cause
Alkali resistance pH 12,5 Method 7 (5 min immersion time at Grade 2 - slightly changed G
room temperature)
(section 6.3.7) according to AA-0055, Table 1
according to AA-0055
Ageing resistance test 48 h at 100 °C Grade 2 - slightly changed G
(section 6.3.8) (without adhesion tests) according to AA-0055, Table 1
according to AA-0026
Coating thickness according to DIN EN ISO 2360 or Coating thickness ≥ 10 µm G, E, Z
(section 6.3.9) according to DIN EN ISO 1463
G General release
E Initial sample inspection
Z Series-accompanying test
