TL_245_EN_2014-11

Group standard TL 245

Issue 2014-11 Class. No.:50223

Descriptors:corrosion protection, surface protection, zinc, aluminum, flake, Delta-Protekt, Delta-Tone, Geomet,

Magni, Zintek

Non-Electrolytically Applied Zinc Flake Coatings

Surface Protection Requirements

Previous issues

TL 245: 1987-08, 1989-10, 1990-01, 1991-03, 1991-11, 1992-10, 1993-07, 1997-12, 2002-10, 2004-12, 2007-06, 2011-07, 2011-09, 2013-12

Changes

The following changes have been made to TL 245: 2013-12:

–Section A.1.6 "Ofl-t647": "GEOMET? 500 PLUS VLh" added

–Applicable documents updated

Always use the latest version of this standard.

Page 1 of 10 This electronically generated standard is authentic and valid without signature.

The English translation is believed to be accurate. In case of discrepancies, the German version is alone authoritative and controlling.

? Volkswagen Aktiengesellschaft VWNORM-2014-06a-patch5

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TL 245: 2014-11

Scope

This standard defines the requirements placed on Cr(VI)-free surface protection types made of zinc flakes and aluminum flakes applied to ferrous materials in a non-electrolytic manner.

The silver-gray flake coatings are 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 with‐stand temperatures such as those occurring, e.g., in the engine compartment (for details, see table 1).

Since this coating process poses no risk of hydrogen-induced embrittlement, it is preferably used as corrosion protection for hardened and high-strength steel parts with tensile strength values >1 000 MPa or hardness values >320 HV. The protection system must be chosen such that the strength and hardness are not negatively affected by the treatment temperatures.

Zinc flake coatings are also suitable for use as a coating for ferrous materials in contact with alumi‐num components (however, not for those in contact with magnesium components).

The coating is not suitable for components

–that serve as electrical conductors (e.g., ground connections)

–inside of engines (e.g., oil chamber) in order to avoid clogging by detached coating particles The coating is only conditionally suitable for components with

–triple squares as per Volkswagen standard VW 01043

VW 01048

–hexagon sockets <5 and cross recesses as per DIN EN ISO 4757

–external thread

–internal thread

–washers with thickness values <1.6 mm

Description See VW 13750, section 2.

Requirements Surface protection types The surface protection types listed in table 1 apply. Examples of systems previously released for components are listed in appendix A.

1 2 3

3.1

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Table 1

3.2

General requirements

Approval of first supply and changes as per VW 01155.

Avoidance of hazardous substances as per VW 91101.

10 finished parts are required for complete testing. For initial sample release of small parts, e.g., threaded fasteners, a test production of >50 kg must be performed.

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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 have the required surface protection type with the pre‐scribed properties. The coatings must adhere firmly to the base material (see section 3.10) and the coatings must not chip or crack due to elastic deformation.

The protective coatings must not have any pores, cracks, damage, or other flaws that negatively affect the corrosion protection and/or function.

The production process and its control must not impair the functional characteristics of the finished part. For example, the coating must not flake or crack when the springs or spring washers are mounted or used as intended.

If the coated components are properly mounted, the coating must not be damaged in a way that would negatively affect the function and/or would reduce the specified corrosion protection.The selection of manufacturers and coating systems must be agreed upon with the Volks‐wagen AG Laboratory (GQL-M/1) and/or with the Audi AG test laboratories (I/GQ-31 and/or N/GQ-551) for each individual component before use.

Threaded parts with metric ISO threads

The coating process must not negatively affect the mechanical and physical properties specified for fasteners. Therefore, the manufacturer must check whether the curing conditions specified by the coating company are suitable for the components to be coated.An essential functional property of threaded parts with metric ISO threads is their adherence to specified coefficients of friction. In order to ensure that the coefficients of friction adhere to 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 Ofl-t615, the coefficients of friction as per

VW 01129 are ensured by means of additional lubrication as per TL 52165. For the release of new coating systems and the detection of faults in the case of complaints during installation, parts with metric ISO threads must be tested as per VW 01131-1 and VW 01131-2.

Metric ISO threads must be designed as per VW 11611. After the coating process, external thread dimensions must not exceed the shaft tolerance zone h in the shaft basis system as per ISO 286and internal thread dimensions must not be below the hole tolerance zone H in the hole basis sys‐tem as per ISO 286.

Especially in the case of threaded parts with top coats, it must be ensured that the surfaces are not impermissibly damaged by processes carried out after the coating process, such as 100% part check, packaging, transport, etc. For more information, see the guideline "Berücksichtigung der Schütt- und Transportprozesse bei der Umstellung auf Cr(VI)-freie Oberfl?chen" ("Consideration of Dumping and Transport Processes During the Changeover to Hexavalent-Chromium-Free Surfa‐ces"), published by Deutscher Schraubenverband e.V. (German Fasteners Association). Rework must always be announced and agreed upon.

For further information, see VW 01110-1, section 3.

Base coating The base coating contains a binding agent and approx. 70% zinc flakes and approx. 10% alumi‐num flakes. The use of zinc dust is not permissible. In order to reliably achieve coatings that have uniform coverage and that satisfy the test requirements defined in section 3.11.2, a multiple-coat‐ing process is required.

3.3 3.4

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Top coat/lubricant additive

In order to improve corrosion protection and to achieve the defined coefficients of friction, addition‐al system-specific top coats must be used, optionally with an integrated lubricant additive. The top coats must be matched to the base coating. They must not cause any functional impairment.

Zinc flake coatings with top coats must not be used if paintability and the bonding of adhesives (al‐so: locking or adhesive coatings for fasteners) are required.

Base material

See drawing or master data list (MDL).

Pretreatment

Usually bright metal. Alternatively (depending on the coating system), a micro-crystalline, thin-layer phosphate coating (1 g/m 2 to 3 g/m 2) is permissible.

Before coating, hot alkaline and/or mechanical cleaning (e.g., abrasive blasting) must be per‐

formed on high-strength and hardened steel parts with tensile strength values >1 000 MPa or hard‐ness values >320 HV.

Exceptions are only permissible following agreement with the Volkswagen AG Laboratory (GQL-M/1) and/or the Audi AG test laboratories (I/GQ-31 and/or N/GQ-551).

Dry film

Composition as per International Material Data System (IMDS).

Dry film thickness Testing as per DIN EN ISO 1463, DIN EN ISO 2064, and DIN EN ISO 2178; position of measuring points for threaded parts with metric ISO thread as per DIN EN ISO 4042.

The average minimum coat thickness must 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 only apply to the head and/or to the face surface and wrench bearing surface; for all other surfaces, the mini‐mum coating thickness is achieved if the anti-corrosion requirements are fulfilled.

Driving recesses and threaded areas must not have any base coat and/or top coat accumulations that might negatively affect the functional properties.Adhesion

A scribing line based on DIN EN ISO 9227 is applied if the component dimensions allow. Adhesive tape with an adhesive strength of (10 ±1) N per 25 mm in width is then used for the adhesion test.The tape is firmly pressed by hand onto the specimen surface and then removed with a sudden motion perpendicular to the surface. Coating must not be removed from a large area. Small parti‐cles of the coating that adhere to the tape are permissible.

NOTE 1:?Suitable adhesive tape for the test is, e.g., "Tesaband 4657".

NOTE 2:?In the case of small parts, the adhesion test can be performed without a scribing line.3.5 3.6 3.7 3.8 3.9 3.10

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Corrosion behavior Test atmosphere: Condensation atmosphere with constant humidity (CH) as per

DIN EN ISO 6270-2

This test is only required for the release of new coating systems. Usually, this test is carried out on coated test panels (for the test scope, see below). Within the framework of an initial sample inspec‐tion, the moisture resistance can also be proven by a certificate issued by the coating material manufacturer.A scribing line based on DIN EN ISO 9227 must be applied. After a test duration of 720 h and eval‐uation as per DIN EN ISO 4628-3, the following requirements must be satisfied in each case as minimum specifications:

–Base metal corrosion on surface: Ri 0

–Base metal corrosion permissible in the area of the scribing line, but no corrosion creepage

Natural salt spray (NSS) test as per DIN EN ISO 9227

The following requirements apply to parts in the Receipt of Goods department of the Volkswagen Group plant using the parts (i.e., after packaging and transport).

NOTE 3:?Usually, the base coat must be applied 3 times in order to safely achieve ≥600 h of re‐sistance to salt spray fog without base metal corrosion.

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 aging (heat aging/re‐

circulated air) 96 h at +180 °C

Requirements for threaded barrel plated goods

–

No base metal corrosion (Ri 0) after a test duration of 600 h without thermal aging –No base metal corrosion (Ri 0) after a test duration of 480 h with thermal aging (heat aging/re‐

circulated air) 96 h at +180 °C

Requirements for components with surface protection types Ofl-t601, Ofl-t610, and

Ofl?t615

–No base metal corrosion (Ri 0) after a test duration of 480 h without thermal aging

Chemical resistance The verification of the resistance to chemicals is only required for the release of new coating sys‐tems. Usually, this test is carried out on coated test panels (for the test scope, see below). As part of the initial sample inspection, resistance to chemicals may also be demonstrated by a certificate issued by the coating material manufacturer.Testing is performed as per DIN EN ISO 2812. The evaluation is performed as per

DIN EN ISO 4628-1. For test media and requirements, see table 2.

3.11

3.11.1 3.11.2 3.11.2.1 3.11.2.2 3.11.2.3 3.12

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Table 2

Applicable documents

The following documents cited in this standard are necessary to its application.

Some of the cited documents are translations from the German original. The translations of Ger‐man terms in such documents may differ from those used in this standard, resulting in terminologi‐cal inconsistency.

Standards whose titles are given in German may be available only in German. Editions in other languages may be available from the institution issuing the standard.

TL 52146Central Hydraulic System Fluid; Lubricant Requirements

TL 52165Lubricant (greenish) for Threaded Fasteners; Material Requirements

TL 52185Reference Engine Oil SAE 5W-30 for Testing of Compatibility with Re‐

spect to Elastomer Materials; Lubricant Requirements

TL 766Brake Fluid; Material Requirements

TL 774Ethylene Glycol-Based Coolant Additive; Material Requirements

TL 788Diesel Fuel; Fuel Requirements

VW 01110-1Threaded Joints; Design and Assembly Specifications

VW 01129Limit Values for Coefficients of Friction; Mechanical Fasteners with Met‐

ric ISO Threads

VW 01131-1Determination of Coefficients of Friction; Practice- and Mounting-Orien‐

ted Testing

VW 01131-2Determination of Coefficients of Friction; Release of New Surface Coat‐

ing Systems

VW 01155Vehicle Parts; Approval of First Supply and Changes

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VW 11611Metric ISO Thread; Limit Dimensions with Protective Coating for Medium

Tolerance Class; External Threads 6gh / Internal Threads 6H

VW 13750Surface Protection for Metal Parts; Surface Protection Types, Codes VW 91101Environmental Standard for Vehicles; Vehicle Parts, Materials, Operat‐

ing Fluids; Avoidance of Hazardous Substances

DIN 267-27Fasteners - Part 27: Steel screws, bolts and studs with adhesive coating,

Technical specifications

DIN 267-28Fasteners - Part 28: Steel screws, bolts and studs with locking coating,

Technical specifications

DIN EN 228Automotive fuels - Unleaded petrol - Requirements and test methods DIN EN ISO 1463Metallic and oxide coatings - Measurement of coating thickness - Micro‐

scopical method

DIN EN ISO 2064Metallic and other non-organic coatings - Definitions and conventions

concerning the measurement of thickness

DIN EN ISO 2178Non-magnetic coatings on magnetic substrates - Measurement of coat‐

ing thickness - Magnetic method

DIN EN ISO 2812-3Paints and varnishes - Determination of resistance to liquids - Part 3:

Method using an absorbent medium

DIN EN ISO 2812-4Paints and varnishes - Determination of resistance to liquids - Part 4:

Spotting methods

DIN EN ISO 4042Fasteners - Electroplated coatings

DIN EN ISO 4628-1Paints and varnishes - Evaluation of degradation of coatings - Designa‐

tion of quantity and size of defects, and of intensity of uniform changes

in appearance - Part 1: General introduction and designation system DIN EN ISO 4628-3Paints and varnishes - Evaluation of degradation of coatings - Designa‐

tion of quantity and size of defects, and of intensity of uniform changes

in appearance - Part 3: Assessment of degree of rusting

DIN EN ISO 6270-2Paints and varnishes - Determination of resistance to humidity - Part 2:

Procedure for exposing test specimens in condensation-water atmos‐

pheres

DIN EN ISO 9227Corrosion tests in artificial atmospheres - Salt spray tests

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Released surface protection systems Ofl-t601

Any system, e.g.:

DELTA-TONE ? 9000

DELTA-PROTEKT ? KL100

GEOMET ? 321

Magni Flake B46

Magni Flake D90

ZINTEK ? 200

Ofl-t602

Any system, e.g.:

DELTA-PROTEKT ? KL100 + DELTA-PROTEKT ? VH300GEOMET ? 321 PLUS 10

ZINTEK ? 200 + ZINTEK ? TOP

Magni Flake B46 + Magni Top T06E

Ofl-t610

DELTA-TONE ? 9000

Magni Flake D90

Ofl-t611

DELTA-PROTEKT ? KL100 + DELTA-PROTEKT ? VH300ZINTEK ? 200 + ZINTEK ? TOP

Ofl-t615

DELTA-TONE ? 9000 + lubricant (greenish) as per TL 52165Magni Flake D90 + lubricant (greenish) as per TL 52165

Appendix A (informative)

A.1

A.1.1 A.1.2 A.1.3 A.1.4 A.1.5

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Ofl-t647

A.1.6

Any system. For fasteners, however, only:

DELTA-PROTEKT? KL100 + DELTA-PROTEKT? VH301.1GZ DELTA-PROTEKT? KL105 + DELTA-PROTEKT? VH301.1GZ GEOMET? 321 PLUS VLh

GEOMET? 500 PLUS VLh

Magni Flake B46 + Magni Top T06E-GZ

ZINTEK? 200 + ZINTEK? TOP LV