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DE-102015201791-B4 - Method for blackening rolling bearing rings

DE102015201791B4DE 102015201791 B4DE102015201791 B4DE 102015201791B4DE-102015201791-B4

Abstract

A method for preparing rolling bearing rings for an alkaline bluing process, wherein an alkaline and acid-free aqueous adhesive foam mixture containing sodium hydroxide is applied to the rolling bearing rings for cleaning purposes, wherein the adhesive foam mixture is sprayed onto the rolling bearing rings, wherein the consistency of the adhesive foam mixture is adjusted so that the adhesive foam mixture adheres firmly to the rolling bearing rings without running or dripping off due to gravity, wherein an exposure time is allowed, then the adhesive foam mixture is removed from the rolling bearing rings and the rolling bearing rings are then subjected to an alkaline bluing process, wherein lanolin adhering to the rolling bearing rings is removed with the aid of the adhesive foam mixture.

Inventors

  • Thilo von Schleinitz

Assignees

  • AKTIEBOLAGET SKF

Dates

Publication Date
20260513
Application Date
20150203

Claims (9)

  1. A method for preparing rolling bearing rings for an alkaline bluing process, wherein an alkaline and acid-free aqueous adhesive foam mixture containing sodium hydroxide is applied to the rolling bearing rings for cleaning purposes, wherein the adhesive foam mixture is sprayed onto the rolling bearing rings, wherein the consistency of the adhesive foam mixture is adjusted so that the adhesive foam mixture adheres firmly to the rolling bearing rings without running or dripping off due to gravity, wherein an exposure time is allowed, then the adhesive foam mixture is removed from the rolling bearing rings and the rolling bearing rings are then subjected to an alkaline bluing process, wherein lanolin adhering to the rolling bearing rings is removed with the aid of the adhesive foam mixture.
  2. Procedure according to Claim 1 , whereby the rolling bearing rings rotate during the application of the adhesive foam mixture.
  3. Method according to one of the preceding claims, wherein the adhesive foam mixture is mechanically removed from the rolling bearing rings.
  4. Method according to one of the preceding claims, wherein the adhesive foam mixture is removed from the rolling bearing rings by wiping.
  5. Method according to one of the preceding claims, wherein an adhesive foam mixture is applied which contains sodium hydroxide in a concentration of 0.5 to 2% by mass.
  6. A method according to one of the preceding claims, wherein an adhesive foam mixture containing anionic surfactants is applied.
  7. Method according to one of the preceding claims, wherein an adhesive foam mixture containing emulsifying surfactants is applied.
  8. A method according to any of the preceding claims, wherein an adhesive foam mixture containing chiral alkanols is applied.
  9. A method according to any of the preceding claims, wherein an adhesive foam mixture is applied which contains adsorbent and release agent.

Description

The invention relates to a method for blackening rolling bearing rings. During the bluing process for rolling bearing rings, especially large ones with an outer diameter of at least one meter, intermediate storage or transport is usually necessary, for example, from the production site to a bluing facility. To prevent corrosion during these waiting periods, it is common practice to apply a corrosion inhibitor to the bearing rings, thus preserving them. This preservation can be achieved, for example, by spraying a preservative oil onto the rings. Since large bearing rings are very expensive, a film-forming agent such as lanolin is typically added to the preservative oil, creating a durable protective film on the rings and thus minimizing the risk of corrosion. For the bluing of rolling bearing rings, an alkaline bluing process has proven effective, as it does not attack the bearing rings or cause grain boundary damage. Such a bluing process produces a very thin bluing layer and is, for example, used in the following applications: DE 10 2007 061 193 A1 It is known that the hot degreasing performed in the known bluing process can remove a number of corrosion inhibitors from the surface of the rolling bearing rings. However, if film-forming agents have been added to the corrosion inhibitor, the alkaline hot degreasing is not sufficiently effective, so that the preservative film is not removed to an adequate degree. The film-forming agents cannot be removed sufficiently with alcohol or acetone either, and they contaminate the bluing baths and disrupt the bluing process. In principle, it is possible to include pickling steps in the bluing process to remove the protective film. However, these pickling steps are so aggressive that they attack the steel surface of the bearing rings, leading to grain boundary damage. DE 602 07 723 T2 Disclosing a liquid degreasing composition comprising an aqueous nitric acid solution containing: at least a first emulsifying non-ionic surfactant consisting of a polyethoxylated fatty alcohol, and at least a second wetting non-ionic surfactant consisting of an ethylene oxide/propylene oxide copolymer. WO 2007/ 033 761 A1 Disclosure reveals an aqueous cleaning agent for hard surfaces, which is applied to the surface to be cleaned by means of a spray dispenser in the form of a foam, and which contains a fatty alcohol sulfate and/or a fatty acid sarcosinate as well as isopropanol and butyl glycol. The agent can be used in a process for streak-free cleaning of hard surfaces, in particular glass. GB 1 162 039 A Disclosing a method for cleaning an open surface with harmful cleaning compositions containing eye, nose, and skin irritants, the method comprises mixing a foamable cleaning composition containing harmful chemicals such as alkalis, mineral acids, sulfamic acid, or strongly basic amines with at least 90% by volume of a gas, applying the resulting foam to the open surface to be cleaned, and rinsing the surface to remove the remaining foamed cleaning composition. DE 10 2012 213 317 A1 reveals a bluing process in which the bearing component to be blued is first degreased. EP 1 121 690 B1 Disclosing a degreasing composition comprising a base, a saturated or unsaturated polyoxyethylated fatty alcohol, a copolymer of ethylene oxide and propylene oxide, and water, wherein the base has an OH⁻ ion concentration selected from the range of 0.1 to 1.5 mol.1-1, wherein the saturated or unsaturated polyoxyethylated fatty alcohol is present in a concentration selected from the range of about 0.01 to about 1.5 wt%, and wherein the copolymer of ethylene oxide and propylene oxide has a concentration selected from the range of about 0.025 to about 1.5 wt%. The invention is based on the objective of enabling bluing by means of an alkaline bluing process, even for rolling bearing rings that have been treated with a corrosion protection agent containing a film former such as lanolin. This problem is solved by the combination of features of claim 1. In the inventive method for preparing rolling bearing rings for an alkaline bluing process, an alkaline and acid-free aqueous-based adhesive foam mixture containing sodium hydroxide is applied to the rolling bearing rings for cleaning purposes, wherein the consistency of the adhesive foam mixture is adjusted so that the adhesive foam mixture adheres firmly to the rolling bearing rings. The adhesive foam mixture adheres to the bearing rings without running or dripping due to gravity, and a certain amount of time is allowed to pass through. The adhesive foam mixture is then removed from the bearing rings, which are subsequently subjected to an alkaline bluing process. This process uses the adhesive foam mixture to remove any lanolin adhering to the bearing rings. The invention has the advantage that the rolling bearing rings are cleaned and degreased gently and thoroughly. Oils, greases, and other contaminants adhering to the rolling bearing rings are removed with