DBL 8451 PDF

All rights reserved. Distribution as well as distribution of pages without permission of DaimlerChrysler AG is not permitted. In case of doubt, the German language original should be consulted as the authoritative text. For this reason the Cr VI -free product versions contained in the following table, which shall comply with these statutory requirements, are marked specially with the supplement Cr VI -free. As of it is necessary for these types of systems to be delivered chromium VI -free in accordance with Page 2 DBL : May this DBL, without the functional properties of the components being impaired or altered in any way. For this coating system the numbering of the product versions does not change when the transition is made to Cr VI -free.

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For this reason the Cr VI -free product versions contained in the following table, which shall comply with these statutory requirements, are marked specially with the supplement Cr VI -free. As of it is necessary for these types of systems to be delivered chromium VI -free in accordance with Continued on pages 2 to 16 Issued by: DaimlerChrysler AG Technical responsibility Name : Dr. All rights reserved. Distribution as well as distribution of pages without permission of DaimlerChrysler AG is not permitted.

In case of doubt, the German language original should be consulted as the authoritative text. For this coating system the numbering of the product versions does not change when the transition is made to Cr VI -free. Abbreviated designations on drawing, in block for surface protection e. For this reason, alongside the corrosion protection, attention shall also be paid to any possible changes in surface-specific functional properties in comparison to coatings containing Cr VI.

Surfaces for parts, which are attached to body shells by means of welding, screw-connection or bonding and which together with the body run through the pre-treatment and painting process, are not parts of this DBL for the supply of materials.

Although the End-of-Life Vehicle Act does not currently apply to heavy-duty trucks or buses, for reasons of variant reduction in new designs, consideration should be given to also specifying Cr VI - free surfaces for commercial vehicle parts. The function properties shall be checked when changing to Cr VI -free surfaces. For notes on corrosion resistance and recommendations for various application cases, see Tables 2 to 4.

The EU End—of-Life Vehicle Directive including the requirements with regard to freedom from Cr-VI shall be complied with for the corresponding identified product versions. In terms of conformity with the provisions of the EU End-of-Life Vehicle Directive, the only decisive matter is whether the material or the component at the time of being put into service as an end product is free from Cr VI or not. Here, it is irrelevant whether material containing Cr VI was used during the production process or not.

Generally, the DBL requirements are valid for declarable substances. Our intention is to maintain this type of documentation in accordance with DIN Page 3 DBL : May 3 General properties of the materials, raw materials and supply condition 3.

These are, e. If necessary, an agreement concerning surface quality may have to be made. Any contamination on the surface of the parts to b treated corrosion products or scale, oil, grease, dirt etc. This also applies if the component strength exceeds this value in some areas only. Production, joining and surface-treatment methods shall be executed such that any damage through delayed hydrogen-induced brittle fracture can be ruled out with a high degree of certainty.

The relevant measures and tests such as minimization of component stresses, selection, composition and checking of chemicals, physical and chemical method limits, type of tests, test frequency, number of specimens etc. The treatment of incorrect coatings removal of coatings and new coatings shall be investigated and the resulting consequences specified.

Investigations shall be documented. In addition to this, the coater is expected to assess the process in detail FMEA with regard to all sub-stages, in which hydrogen could ingress into the material structure. If necessary, the processes shall be optimized.

Process assessment shall be safeguarded by means of component tests. Measures shall be derived from this, which serve to reliably minimize the quantity of hydrogen ingressing into the material during the process, and which enable a regular periodic examination of the efficiency of such measures. Refer to DIN , Section 4. Care shall be taken to ensure that the properties of the parts are not impaired in this process. Effusion treatment following a strike deposit layer thickness 2?

If the heat treatment is performed in the ready plated condition, however, particular care shall be taken to ensure that the applied metal plating does not act as diffusion barrier and prevent the success of the heat treatment with regard to hydrogen effusion. The effectiveness of the heat treatment shall always be documented. The ideal heat treatment s used for a part temperature, duration, operating sequence shall be ascertained and stated in the ISIR initial sample inspection report.

These include:? Preloading tests on real-life components that have been zinc-coated in a deformed fixture, in which the component is subjected to stress close to the weld seam through stresses in the yield strength area.

A sufficient number of in-process preloading tests on suitable hydrogen sensitive samples shall be used as the basis for establishing the suitability of the process for coating critical components. For particularly critical parts, a switch shall be made to DBL and acid-free pretreatment. In exceptional cases unavoidable bolts of property class The threaded parts concerned shall be converted and shall no longer be delivered according to DBL For safety-critical fasteners, property class acc.

A uniform appearance of the surface shall also be provided in a passivated and, where applicable, sealed condition. Due to the geometry, it may not be possible to apply the coating to all surfaces, e. Care shall be taken to ensure that uncoated surface areas do not exhibit any deposits, corrosion products or any other residue formation.

Damage to the coating through improper handling of the parts after electroplating, e. These companies, with their regulated process control and intensive quality assurance measures are most likely to consistently comply with the requirements contained within this DBL. Before commencement of production deliveries, the coater shall determine and record the complete pre-treatment and coating process, the physical data treatment periods, temperatures and the composition of all process chemicals, and, if required, optimize them.

Individual process intervention limits as well as the frequency of monitoring and analysis procedures shall be defined. The resulting measures shall be specified by the coater. The documentation for this process specification shall be submitted to DaimlerChrysler when requested during audits. Confidentiality of the revealed data shall be assured.

Any changes to the production coating process, which - subject to state-of-the-art technology - may exert an influence on the properties of the base material or the coating, shall be notified to DaimlerChrysler immediately and without further request.

This will result in the parts having to undergo a new sample delivery. In contrast to national and international standards, these Supply Specifications do not differentiate between the manufacturing process for barrel or rack coating, because often when determining the surface protection required, the process technology used is not yet known. In many cases, parts with a thread bolts, nuts can be coated in the drum. For information on the achievable corrosion resistance for barrel and rack parts, refer to VDA specification VDA which is based on comprehensive interlaboratory tests.

The stated requirement values — transferred to the procedure of this DBL — are in many cases comparable and currently represent state-of-the-art technology. The method used and the nickel content specified and actual values in the layer shall be indicated in the initial sample inspection report ISIR. The significantly higher corrosion resistance of the metallic coating in combination with the less prominent corrosion products compared to pure zinc coatings and the low-alloyed zinc-iron coatings are characteristic of zinc-nickel coatings.

Zinc-nickel coatings therefore demonstrate the best behavior of the metallic coatings within this DBL with regard to corrosion protection quality. The methods used and the content of the alloy element s specified and actual values in the layer shall also be stated in the initial sample inspection report ISIR.

The low-alloy zinc-cobalt coatings formerly available in France are no longer as important, and for this reason they are not included in this DBL.

For any parts currently still in delivery phase which have a ZnCo coating, the requirements specified in DBL , edition Page 6 DBL : May 3. While chromating is produced from solutions containing Cr VI and the chromating on the workpiece may therefore also contain Cr VI , the term passivation refers to chromium VI -free corrosion protection. Passivation treatments are conversion layers and they are created by immersing the components in passivation solutions.

By doing so the newly electrodeposited coating reacts with the passivation solution to form a thin film composed of complicated reaction products, which cover the metallic coating. The reaction always causes the coating to dissolve partially approx. If necessary, this process shall be counteracted by increasing the electrodeposited layer thickness. This in turn causes some of the metallic coating to be dissolved, and a chromate coating is formed consisting of the various chemical constituents in the coating and the chromating solution ingredients.

Whereas for colored chromate coatings yellow, black, olive one can assume that they contain Cr VI compounds, this is not assured for transparent or blue chromate coatings. To be certain that Cr VI -free products are used a conversion to the special product versions of this DBL is necessary. For PVs. Top coats or subsequent paintwork with higher layer thickness shall not be used as sealings. This usually also serves to remove any interference color. Whereas formerly sealing was mainly performed using organic resin dissolved in water, recent developments have seen products used which contain nanoscaled SiO2, partly in combination with organic resin.

When sealing, special care shall be taken to ensure that the inner surfaces of tubes fulfill residual contamination requirements, or that they are compatible with the operating fluids. Sealings for product versions. The use of special products may become necessary in this respect. The use of sealants with integrated lubricants which may have an effect on the sliding properties of the finish is not permitted in principle with regard to these components. Any deviations shall be agreed and documented separately.

Parts that subsequently undergo electrophoretic dip coating cataphoretic dip coating, anodic dip coating shall not be sealed. The coater shall be notified of this. Page 7 DBL : May 3. The coatings are used for corrosion protection under the most stringent of requirements and for deep-black coloration.

Pure zinc coatings, and high-alloy zinc-alloy coatings ZnNi are used for metallic base coatings. Parts are generally coated in barrels, baskets, trays or on belt and rack technology. These types of coating systems are standardized as "duplex coatings" in DIN However, the standard is not valid for fasteners with threads.

The applicability of these types of coating systems shall be ascertained in each case by means of suitable investigations. The type of additional coating is subject to agreement. The methods and products used shall be indicated in each case in the ISIR initial sample inspection report as part of the initial sample process. In such instances, the areas essential for surface protection shall be specified.

Essential areas shall be designated on a drawing by means of a dot-and-dash line. The requirements contained within this DBL apply to these areas only.

For product versions. Screws, bolts and nuts with coarse-pitch or fine-pitch thread, which are manufactured according to this DBL and not according to DBL , should always be treated with antifriction agent, insofar as this is not ruled out by other reasons, for example the need for an additional coating with adhesives.


Zinc-Nickel (Zn-Ni)

Zinc-Nickel Zn-Ni The electrolytic plating process zinc-nickel stands out with very good corrosion protection and a high thermal resistance. Zinc-Nickel Plating: process and advantages Zinc-nickel platings were developed as a result of increasing requirements with regard to corrosion protection, in particular from the automotive industry, against exposure to temperature, road salt and climatic conditions. Zinc-nickel platings are normally used if the traditional zinc-plating process is insufficient, due to high temperatures or aggressive environmental conditions. This type of surface finish is usually used on steel, ferrous cast components and powdered metals. We offer various Cr VI -free post finishing treatments for zinc-nickel surfaces: Passivations are available in black or transparent form.






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