TL 52132_EN_2004

The English translation is believed to be accurate. In case of discrepancies the German version shall govern. Lubricant for Threaded Fastening Elements with Electrolytically Applied Coatings or those of Stainless Steel Requirements TL 521 32 Konzernnorm Descriptors: lubricant, electrolytically zinc coated, Cr(VI)-free, stainless steel, threaded fastening element, screw, bolt, coefficient of friction Changes The following changes have been made as compared to Technical Supply Specification TL 521 32, 1986-01: 󰅆 󰅆 Standard restructured Content revised Previous issues 1986-01 1 Scope This Technical Supply Specification stipulates the requirements for lubricants in electrolytically produced zinc and zinc alloy systems – Cr(VI)-free – for metric threaded fastening elements with surface protection types according to Volkswagen standard VW 137 50 and for joining elements made from stainless, high-alloyed chromium steel. 2 Designation Lubricant according to TL 521 32 3 3.1 Requirements General requirements Approval of first supply and changes according to VW 011 55. Avoidance of hazardous substances according to VW 911 01. When fastening, the lubricant coating must 󰅆 󰅆 reduce the coefficient of friction (total friction coefficient range µtot = 0.09 to 0.15; see VW 011 29) and narrow the scatter range. as compared to untreated threaded fastening elements. The lubricant coating must be suitable for Cr(VI)-free zinc coatings and must not itself contain Cr(VI). In order to check the coating (Yes/No statement), a UV inhibitor must be contained as an indicator. 3.2 Standard part number N 052 132 00 Form FE 41 - 01.03 Page 󰀓󰀂󰁑󰁈󰀂󰀕 Fachverantwortung/Responsibility 2-NQ-HK4 Dr. Maikowski Tel: -4533 Normung/Standards (EZTD, 1733) Frau Hager-Süß Tel: +49-5361-9-49035 Sobanski Confidential. All rights reserved. No part of this document may be transmitted or reproduced without the prior written permission of a Standards Department of the Volkswagen Group. Parties to a contract can only obtain this standard via the responsible procurement department. © VOLKSWAGEN AG Norm vor Anwendung auf Aktualität prüfen / Check standard for current issue prior to usage. Klass.-Nr. 57 25 4 August 2004 Page 2 TL 521 32: 2004-08 3.3 Type Water-dispersed synthetic polymers (PE suspension) that, after application and drying, produce a friction film/layer that is resistant to handling (commercial products include, for example, Microgleit DF 911/DF 921 produced by the Microgleit company, Gleitmo 605/625 from Fuchs Lubritec or Torque’N’Tension Control Fluid from the MacDermid company). Note: The properties of the products differ in part and must be tested for the relevant application with respect to the friction coefficients to be achieved. Special influences such as threading speeds, counter layers and operational temperatures of the joining elements in contact must be taken into consideration. Thus, for example, Microgleit DF 911, Gleitmo 605 and T’N’T Control Fluid are particularly suited for coating galvanized joining elements. Gleitmo 625 and Microgleit DF 921 are preferred for stainless steel joining elements; the coefficient-of-friction-reducing effect is particularly strong here. The coating medium must be silicone-free and must not contain any substances that would require it to be labeled as hazardous to health (Xn) according to the Hazardous Substances Regulation. 3.4 󰅆 󰅆 Requirements for the lubricant coating process It must be ensured that no residues of chromic acid, chromic solutions or other acid residues can enter into the lubricant coating bath. A process-sure, even wetting of the surface with lubricant shall be guaranteed. Before the lubricant is applied, the parts to be coated should be dry and warmed slightly (approx. 40 °C to 50 °C; not above 75 °C). The temperature of the coating medium must not drop below 20 °C during the coating process (optimal: 25 °C to 35 °C; not above 75 °C). The coating medium is generally supplied as a concentrate. The mixing ratio of the coating medium concentrate and water must be selected such that the required friction coefficients are achieved and maintained. Empirical standard value: 1 part coating medium to 3 parts water (e.g., for Microgleit DF 911, Gleitmo 605 or Torque’N’Tension Control Fluid). The bath concentration shall be tested by determining the dry residue or using a refractometer, and documented. The bath must be checked (pH value) in accordance with the specifications of the coating medium manufacturer (frequency: minimum 1 x per shift/day, taking into consideration the specified limit values). Coated threaded parts should preferably be dried in a through-type system, but a centrifugal system is also possible. Drying must be performed at a speed suited to the parts spectrum and with the application of heat. The exact settings (speed, temperature, filling quantity) are to be determined by the coating operator in cooperation with the coating medium manufacturer, and documented. Here, the maximum permitted temperature for the coating system must be observed, e.g., max. 90 °C for Cr(VI)-free passivation treatments. In order to avoid the risk of condensation, the parts shall be packed in a dry state and only after reaching ambient (room) temperature. The efficacy of the lubricant coating with respect to the friction coefficients of the threaded fastening elements is to be checked in coordination with the accepting factory. 󰅆 󰅆 󰅆 󰅆 󰅆 󰅆 Note: If elements that have already been coated with lubricant are coated once again, this can yield different friction coefficients than for the first coating. Page 3 TL 521 32: 2004-08 4 Referenced standards*) Limit Values for Coefficients of Friction; Mechanical Joining Elements with Metric ISO Thread Vehicle Supply Parts; Approval of First Supply and Changes Surface Protection of Metal Parts; Degrees of Protection, Codes, Requirements Environmental Standard for Vehicles; Vehicle Parts, Materials, Operating Fluids; Avoidance of Hazardous Substances VW 011 29 VW 011 55 VW 137 50 VW 911 01 *) In this section, terminological inconsistencies may occur as the original titles are used.