Klass.-Nr./Class. No. 50223
June 2007
Non-Electrolytically Applied Zinc Flake Coatings
TL 245
Surface Protection Requirements Requirements
Konzernnorm Descriptors: corrosion protection, surface protection, zinc, aluminum, aluminum, flake, Delta-Protekt, Delta-Tone, Geomet, Magni, Zintek . n r e v o g l l a h s n o i s r e v n a m r e G e h t s e i c n a p e r c s . i ) d f 0 0 o 0 e 1 s 0 a c W n V I . e e t e s a r ( u e c i c c t a c e a b r p o O t d I S e v t o e i l e g n b i r s d i o n c o c i t a a n l s i o n t a a r t t o n h l s i l a g i c n r E e e m h u T N
Changes The following changes have been made as compared to Technical Supply Specification Specification TL 245, 2004-12: ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─
Section 1 "Scope" updated. Surface protection type Ofl-t601 added Table 2 updated Section 3.1 "Dry film thickness" updated Section 3.3 "Threaded parts with metric ISO standard threads" updated Section 3.4 "Base coating" updated Section 3.5 "Top coat/lubricant coat/lubricant additives" updated Section 3.7 "Pretreatment" updated Section 3.9 "Dry film thickness" updated Section 3.10 "Adhesion" updated Section 3.11 "Corrosion behavior" updated Section 3.12 "Resistance to chemicals" updated Referenced standards updated Appendix A updated updated
Previous issues 1987-08, 1989-10, 1990-01, 1991-03, 1991-11, 1992-10, 1993-07, 1997-12, 2002-10, 2004-12 1
Scope
This standard defines the requirements on Cr(VI)-free surface protection types made of zinc flakes and aluminum flakes non-electrolytically applied to ferrous materials. Silver-gray flake coatings shall be used as heavy-duty corrosion protection for components with a high corrosion load. With an appropriate layer structure, the zinc-flake coatings are able to withstand temperatures, such as those occurring in the engine compartment, for example (details see Table 1). Since this coating process poses no risk of hydrogen-induced brittling, it is preferably used as corrosion protection for hardened and high-strength steel parts with tensile strength values > 1 000 MPa or surface hardness values > 320 HV. The protection system shall be chosen such that the strength and hardness are not impaired by the treatment temperatures. Zinc-flake coatings are also suitable for use as a coating for ferrous materials in contact with aluminum components components (however, not for those in contact with magnesium components). The coating is not suitable not suitable for parts ─ ─ 6 0 . 1 0 1 4 E F m r o F
that serve as electrical conductors (e.g. ground connections), with 12-point sockets acc. to Volkswagen Standard VW 01043 < N8 and hexalobular sockets acc. to VW 01048 < T30, Page 1 of 9
Fachverantwortung/Technical responsibility K-GQL-2/2 Ackermann Tel: +49-5361-9-38255
K-GQL-2/2 Laudien
Normung/Standards K-GQL-2 Dr. Eisenberg
EKTC/4 Wiesner Tel.: +49-5361-9-29064
EKTC
Terlinden
Confidential. All rights reserved. No part of this document may be transmitted or reproduced without prior permission of a Standards Department of the Volkswagen Group. Parties to a contract can only obtain this standard via the B2B supplier platform “www.vwgroupsupply.com”.
VOLKSWAGEN AG
. e g a s u o t r o i r p e u s s i t n e r r u c r o f d r a d n a t s k c e h C / n e f ü r p t ä t i l a u t k A f u a g n u d n e w n A r o v m r o N
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with hexagon sockets < 5 and cross recesses according to DIN EN ISO 4757 < H3 with external threads < M6 and internal threads < M10 with washers with a thickness of < 1,6 mm
In order to avoid problems caused by coating particles that come loose, zinc flake coatings should only be used inside units (e.g. oil chamber) in exceptional cases. 2
Description
See VW 13750, Section 2. 3
Requirements
3.1
Surface protection types
The surface protection types listed in Table 1 apply; for replacement of surface protection types that are no longer permitted, see Table 2. Examples of systems that were previously released partspecifically are listed in Appendix A.1. Table 1 Protection type Ofl-t601
Characteristics and appearance Base coating without top coat and without lubricant additive. Zinc flake coating, Cr(VI)-free, silver-gray; suitable for components that are to be painted. curing temperature up to max. +300 °C ─ reduced corrosion resistance (see Section 3.11) ─ reduced endurance service temperature without additional coatings ─ (+125 °C)
Ofl-t602
Base coating with top coat, without lubricant additive. Zinc flake coating, Cr(VI)-free, silver-gray; use in exposed installation positions, e.g. in the engine compartment and chassis areas. curing temperature up to max. +300 °C ─ endurance service temperature max. +180 °C (short-term ─ temperature peaks up to +300 °C)
Ofl-t610
Ofl-t611
As for Ofl-t601, but with lower curing temperature. Zinc flake coating, Cr(VI)-free, silver-gray; corrosion protection preferably for components that are to be painted (body construction). Standard surface protection for threaded parts with adhesive coating (DIN 267-27) or with locking coating (DIN 267-28). curing temperature up to max. +200 °C ─ reduced corrosion resistance (see Section 3.11) ─ reduced endurance service temperature without additional coatings ─ (+125 °C) As for Ofl-t602, but with lower curing temperature. Consequently, suitable for components that cannot be exposed to high temperatures, e.g. spring elements, press-quenched sheets or high-strength steel parts. curing temperature max. +230 °C ─ endurance service temperature max. +200 °C (short-term ─ temperature peaks up to +300 °C)
Page 3 TL 245: 2007-06
Table 1 (continued) Surface protection type Ofl-t615
Characteristics and appearance As for Ofl-t610, but additionally with lubricant (greenish) acc. to TL 52165. Standard surface protection for nuts with non-metallic locking element. ─ ─ ─
Ofl-t647
curing temperature up to max. +200 °C reduced corrosion resistance (see Section 3.11) reduced endurance service temperature without additional coatings (+125 °C)
Base coating with top coat, with lubricant additive. Zinc flake coating, Cr(VI)-free, silver-gray, standard surface protection for threaded parts with metric ISO threads (see VW 01110-1). curing temperature up to max. +300 °C ─ endurance service temperature max. +180 °C (short-term ─ temperature peaks up to +300 °C)
Table 2 Surface protection type not permitted for new designs
Protection type designated for new designs
Components of a general nature Ofl-t300
Ofl-t601
Ofl-t310
Ofl-t610
Ofl-t320
Ofl-t611
Ofl-t600
Ofl-t602
Ofl-t620
Ofl-t611 1)
Threaded parts with metric ISO threads Ofl-t300
Ofl-t647 2)
Ofl-t310
Ofl-t647 2)
Ofl-t320
Ofl-t647 2)
Ofl-t345
Ofl-t647 3)
Ofl-t600
Ofl-t647 2)
Ofl-t620
Ofl-t647 2)
Ofl-t645
Ofl-t647 3)
1)
Ofl-t611 stipulates a lower endurance service temperature than Ofl-t620.
2)
Ofl-t601 or Ofl-t610, if component is installed in body construction before painting. Ofl-t610 for threaded parts with locking coating or adhesive coating
3)
Ofl-t615 for nuts with non-metallic locking element.
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3.2
General requirements
Approval of first supply and changes according to VW 01155. Avoidance of hazardous substances according to VW 91101. 10 finished parts are required for complete testing. For first-sample release of small parts, e.g., threaded fastening elements, a test production of > 50 kg shall be performed. The coating materials must not contain any Cr(VI) compounds in order to ensure that the resultant coatings are likewise Cr(VI)-free. Unless certain sections of a part that are marked in the drawing are excluded from the surface coating, the entire surface of the parts must comply with the required surface protection type and display the prescribed properties. There shall be firm adhesion between coatings and base material (see Section 3.10) and there shall be no flaking of the coating or cracks under elastic deformation. The protective coatings must not exhibit any pores, cracks, damage, or other flaws that impair the corrosion protection and/or function. The production process and its control shall not impair the functional characteristics of the finished part. Thus for example, the coating must not flake or crack when the springs or spring washers are mounted or used as intended. With proper mounting, the coating shall not be damaged in a way that would result in impairment of function and/or decrease in the specified corrosion protection. For each individual part, the selection of suppliers and coating systems is subject to agreement, prior to usage, with the Volkswagen AG Group Laboratory (K-GQL-2/2) and/or the Audi AG Test Laboratories (I/GQ-322 and N/GQ-551). 3.3
Threaded parts with metric ISO threads
The coating process must not impair the mechanical and physical properties specified for joining elements. Therefore, the manufacturer shall check whether the curing conditions specified by the coating company are suitable for the parts to be coated. An essential functional property of threaded parts with metric ISO threads is their compliance with specified coefficients of friction. In order to ensure that the coefficients of friction comply with VW 01129, a top coat with integrated lubricant additive is prescribed for surface protection type Ofl-t647, in addition to the base flake coating. For releases of new coating systems and for the detection of faults in the case of objections during installation, parts with metric ISO threads shall be tested acc. to VDA 235-203. Prior to coating, threaded parts shall respect a tolerance zone position corresponding to the coating thickness. Metric threaded parts shall preferably be designed according to VW 11624 (internal threads) or VW 11627 (external threads). After the coating process, the zero line must not be exceeded in the case of external threads, and it must not be fallen below in the case of internal threads. Especially in the case of threaded parts with top coat, it shall be ensured that the surfaces are not impermissibly damaged by processes carried out after the coating process, such as 100% verification, packaging, transport, etc. For more information, see guideline "Berücksichtigung der Schütt- und Transportprozesse bei der Umstellung auf Cr(VI)-freie Oberflächen" (Consideration of Handling and Transport Processes during the Changeover to Hexavalent-chromium-free Surfaces, currently only available in German), published by Deutscher Schraubenverband e.V. (German Fasteners Association). On principle, rework shall be announced and agreed upon. For further information see VW 01110 -1, Section 2.
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3.4
Base coating
The base coating contains a binding agent and approx. 70% zinc flakes and approx. 10% aluminum flakes. The use of zinc dust is not permissible. In order to achieve homogeneously covering coatings in a reliable process and in compliance with the test requirements defined in 3.11.2, multiple coating is necessary. 3.5
Top coat/lubricant additive
In order to improve the anti-corrosion requirements and to achieve the defined coefficients of friction, additional system-specific top coats, optionally with integrated lubricant additive, may be used. The top coats must be coordinated to suit the base coating. They must not cause any functional impairment. Zinc flake coatings with top coats shall not be used if paintability and adhesion of adhesives (also: locking or adhesive coatings for fasteners) are demanded. 3.6
Base material
See drawing. 3.7
Pretreatment
Principally plain metal. Optionally (depending on the coating system) micro-crystalline thin layer phosphating (1 g/m² to 3 g/m²) is permissible. Prior to coating, hot alkaline and/or mechanical cleaning (e.g. abrasive blasting) shall be carried out on high-strength or hardened steel parts with a tensile strength > 1 000 MPa or surface hardnesses > 320 HV. Exceptions are only permissible after agreement with the Volkswagen AG Group Laboratory (K-GQL-2/2) and/or the Audi AG Test Laboratories (I/GQ-322 and N/GQ-551). 3.8
Dry film
Composition acc. to International Material Data System (IMDS). 3.9
Dry film thickness
Testing according to DIN EN ISO 1463, DIN EN ISO 2064 and DIN EN ISO 2178; measuring point position for threaded parts with metric ISO standard thread according to DIN EN ISO 4042. The average minimum coat thickness shall be 8 µm; the results of the individual measurements may vary within the range from 6 µm to 20 µm. For threaded parts, the specifications shall only apply to the head and/or to the face and wrench bearing surfaces; for all other surfaces, the minimum coating thickness is achieved if the anti-corrosion requirements are fulfilled. Internal drives and threaded areas must not exhibit any accumulations of base coat and/or t op coat that might impair the functional properties.
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3.10
Adhesion
A scribing line shall be applied on the basis of DIN EN ISO 9227, component dimensions permitting. Adhesive tape with an adhesive strength of (10 ± 1) N per 25 mm in width is then used for the adhesion test. It shall be firmly pressed by hand onto the specimen surface and then removed with a jerk-like motion perpendicular to the surface. There must be no large-area removal of the coating. Small particles of the coating that adhere to the tape are permissible. 3.11
Corrosion behavior
3.11.1
Test atmosphere CH acc. to DIN EN ISO 6270-2
This test is only required for the release of new coating systems. Generally, this test is carried out on coated test panels (test scope see below). Within the framework of a first-sample test, the moisture resistance can also be proven by a certificate issued by the coating material manufacturer. A scribing line shall be applied on the basis of DIN EN ISO 9227. After a test duration of 720 h and evaluation according to DIN EN ISO 4628-3, the following minimum requirements must be adhered to at all times: ─ ─
Base metal corrosion on surface: Ri 0. base metal corrosion permissible in the scribing line, but no rust creep.
3.11.2
NSS test acc. to DIN EN ISO 9227
The following requirements apply to parts in the goods reception department of the Volkswagen Group plant using the parts (e.g. after packing and transport). 3.11.2.1 Requirements for components of a general nature ─ ─
No base metal corrosion (Ri 0) after a test duration of 720 h. No base metal corrosion (Ri 0) after a test duration of 480 h with thermal conditioning (aging at elevated temperature/mechanically circulated air) 96 h at +180 °C.
3.11.2.2 Requirements for threaded barrel plated goods ─ ─
No base metal corrosion (Ri 0) after a test duration of 600 h without thermal conditioning. No base metal corrosion (Ri 0) after a test duration of 480 h with thermal conditioning (aging at elevated temperature/mechanically circulated air) 96 h at +180 °C.
3.11.2.3 Requirements for components with the protection types Ofl-t601, Ofl-t610 and Ofl-t615 ─
No base metal corrosion (Ri 0) after a test duration of 480 h without thermal conditioning.
3.12
Resistance to chemicals
The verification of the resistance to chemicals is only required for the release of new coating systems. Generally, this test is carried out on coated test panels (test scope see below). Within the framework of a first-sample test, the resistance to chemicals can also be proven by a certificate issued by the coating material manufacturer. Test according to VDA 621-412 in the following media:
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FAM test fuel according to VDA 621-412, test A 4.1.1 Y Diesel fuel according to TL 788 and VDA 621-412, test A 4.1.2 X Biodiesel (FAME) according to DIN EN 14214 and VDA 621-412, test A 4.1.2 X Gasoline, premium unleaded per DIN EN 228 and test according to VDA 621-412, test A 4.1.3 Y Factory-fill engine oil according to TL 52173 (Burmah Castrol Oil code A97075PBC) and VDA 621-412 test A 4.1.4 X Hydraulic fluid according to TL 52146 and VDA 621-412, test A 4.1.6 X Automatic transmission fluid according to TL 52162 and VDA 621-412, test A 4.1.7 X Coolant according to TL 774 and VDA 621-412, test A 4.2.2 X
A surface change is not permitted (≤ code 1 acc. to DIN EN ISO 4628-1). Additionally, tests are performed in the following medium: ─
Brake fluid according to TL 766 and VDA 621-412, test A 4.2.1 X.
The following requirement applies to this medium: Swellings that have corrected themselves after 24 h are permissible. 4
Referenced standards*
TL 766
Brake Fluid; Material Requirements
TL 774
Ethylene Glycol-Based Coolant Additive; Material Requirements
TL 788
Diesel Fuel, Fuel Requirements
TL 52146
Central Hydraulic System Fluid; Lubricant Requirements
TL 52162
Factory-Fill-for-Life Automatic Transmission Fluid; Lubricant Requirements
TL 52165
Lubricant (Greenish) for Threaded Fasteners; Material Requirements
TL 52173
Factory-Fill Engine Oil SAE 0W-30 with Fuel-Saving Properties for Extended Oil Change Intervals; Requirement, Testing
VW 01043
Multipoint Socket Profile; Drive Shape for Threaded Parts
VW 010 48
Round Hexagon Socket; Drive Shape for Threaded Parts
VW 01110-1
Threaded Joints, Design, Assembly Instructions (currently only available in German)
VW 01129
Limit Values for Coefficients of Friction; Mechanical Joining Elements with Metric ISO Thread
VW 01155
Vehicle Supply Parts; Approval of First Supply and Changes
VW 11624
Metric ISO Thread; Limit Dimensions for 6G/6f Tolerance Zone, Male 6f, Female 6G
VW 11627
Thread Limit Dimensions for External Threads of Tolerance Class 6e; Metric ISO Threads
VW 13750
Surface Protection of Metal Parts; Surface Protection Types, Codes
VW 91101
Environmental Standard for Vehicles; Vehicle Parts, Materials, Operating Fluids; Avoidance of Hazardous Substances
VDA 621-412
Anstrichtechnische Prüfungen; Chemikalienbeständigkeit von KraftfahrzeugLackierungen (Tests for Coating Methods; Resistance to Chemicals of Motor Vehicle Paints; only available in German)
*
In this Section, terminological inconsistencies may occur as the original titles are used.
Page 8 TL 245: 2007-06
VDA 235-203
Threading Behavior; Coefficients of friction; Practice- and Mounting-Oriented Testing (currently only available in German)
DIN 267-27
Fasteners - Part 27: Steel Screws, Bolts and Studs with Adhesive Coating; Technical Specifications
DIN 267-28
Fasteners - Part 28: Steel Screws, Bolts and Studs with Locking Coating; Technical Specifications
DIN EN 228
Automotive Fuels – Unleaded Petrol – Requirements and Test Methods
DIN EN 14214
Automotive Fuels – Fatty Acid Methyl Esters (FAME) for Diesel Engines – Requirements and Test Methods
DIN EN ISO 1463
Metallic and Oxide Coatings – Measurement of Coating Thickness – Microscopical Method
DIN EN ISO 2064
Metallic and Other Non-Organic Coatings - Definitions and Conventions Concerning the Measurement of Thickness
DIN EN ISO 2178
Non-Magnetic Coatings on Magnetic Substrates –Measurement of Coating Thickness – Magnetic Method
DIN EN ISO 4042
Fasteners – Electroplated Coatings
DIN EN ISO 4628-1 Paints and Varnishes – Evaluation of Degradation of Coatings; Designation of Quantity and Size of Defects, and of Intensity of Uniform Changes in Appearance – Part 1: General Introduction and Designation System DIN EN ISO 4628-3 Paints and Varnishes – Evaluation of Degradation of Coatings; Designation of Quantity and Size of Defects, and of Intensity of Uniform Changes in Appearance – Part 3: Assessment of Degree of Rusting DIN EN ISO 4757
Cross Recesses for Screws
DIN EN ISO 6270-2 Paints and varnishes - Determination of Resistance to Humidity - Part 2: Procedure for Exposing Test Specimens in Condensation-Water Atmospheres DIN EN ISO 9227
Corrosion Tests in Artificial Atmospheres - Salt Spray Tests
Page 9 TL 245: 2007-06
Appendix A (informative) A.1
Released surface protection systems
A.1.1
Ofl-t601
Any system, e.g.: DELTA-TONE 9000 DELTA-PROTEKT KL100 GEOMET 321 Magni Flake B46 Magni Flake D90 ZINTEK 200 A.1.2
Ofl-t602
Any system, e.g.: DELTA-PROTEKT KL100 + DELTA-PROTEKT VH300 GEOMET 321 PLUS 10 ZINTEK 200 + ZINTEK TOP Magni Flake B46 + Magni Top T06E A.1.3
Ofl-t610
DELTA-TONE 9000 Magni Flake D90 A.1.4
Ofl-t611
DELTA-PROTEKT KL100 + DELTA-PROTEKT VH300 A.1.5
Ofl-t615
DELTA-TONE 9000 + lubricant (greenish) acc. to TL 52165 Magni Flake D90 + lubricant (greenish) acc. to TL 52165 A.1.6
Ofl-t647
Any system. However, for joining elements only: DELTA-PROTEKT KL100 + DELTA-PROTEKT VH301GZ GEOMET 321 PLUS VL Magni Flake B46 + Magni Top T06E-GZ ZINTEK 200 + ZINTEK TOP LV
