It is noted that a grave shortcoming of trivalent baths is their low conductivity in comparison with the hexavalent ones. There is no need to utilize toxic lead anodes in Cr(III) deposition processes. The covering power of the Cr(III) baths is poorer than in case of hexavalent chromium baths it may be improved by applying basic chromium sulfate (chrome tanning agent) instead of chromium sulfate as a source of Cr(III) ions in solution. The proposed trivalent chromium baths are distinguished by their high current efficiency and electrodeposition rate. It is shown that thick nanocrystalline chromium-carbon deposits may be obtained from the Cr(III) electrolytes under study, with some physicochemical and service properties of such coatings exceeding those of ''usual'' chromium deposits. The main technological properties of sulfate trivalent chromium baths containing carbamide and formic acid as organic additives are described and compared to those typical of common Cr(VI) plating bath. In this research the effect of PEG 4000 addition and solution temperature variation was o bserved to achieve. Plant records were consulted, chrome repair during previous repair was discovered GE-Bently Nevada (vibration probe manufacturer) contacted Custom logic provided for 410SS w/ 0.In this communication, we present a generalization of our investigations concerning current state in the development of trivalent chromium baths as an environmentally friendly alternative to hazardous electroplating baths containing extremely toxic hexavalent chromium compounds. chromium plating is more difficult to undertake than hexavalent hard chromium plating. Actual vibration registered by handheld: in/s 2015 FSRUGġ5 GE-Bently Nevada (vibration probe manufacturer) contactedĬase Study Continued. After discussions between RER and plant engineering, proximity probe logic adjusted to subtract 2 mils to allow further readings to be taken Hand held vibration equipment 2015 FSRUGġ4 Actual vibration registered by handheld: 0.07-0.08 in/sĬase Study Continued. Pump ran for approximately 4-8 seconds before IB proximity probe registered vibrations of 4.69 mils resulting in a trip 2015 FSRUGĬase Study Continued. Slope of linear relationship between air gap and DC voltage is strongly material dependent This relationship can be dramatically changed with the addition of a chromium layer 2015 FSRUGġ1 Case Study In April 2011, a newly rebuilt Flowserve CHTA BFP trips upon initial startup due to high vibration readings 2015 FSRUGġ2 Case Study Continued. Bearing journal damage on a high speed feedpump shaft Damage was repaired via hard chrome plating and grinding 2015 FSRUGĮddy Current Transducer Modulations in DC voltage directly proportional to air gap distance between probe tip and shaft surface Modulations in AC voltage directly proportional to vibration 2015 FSRUG High abrasion resistance Corrosion resistant 2015 FSRUGĭimensional restoration Bearing journals, shaft fits, impeller bores, etc. Follow the link for a list of some shops that offer hard chrome plating. fDecorative chromium plating provides a durable coating with a pleasing appearance and is usually deposited in a thickness range of 0.002 to 0.020 mils. In contrast, thin dense chrome plating has a thickness from 0.0002 to 0.0006 inch (0.005 to 0.015 mm). This Technology Profile is for the use of trivalent chromium processes as replacements for decorative and hard hexavalent chromium processes. (from 0.020 to 0.127 mm) thick on the surface of the metal. Hard chrome plating leaves a layer of chrome from 0.0008 to 0.0050 in. Ultra Hard (65-70 HRC) High galling resistance Excellent adhesion (>10,000 PSI) Adheres to a wide range of materials Steel, Stainless Steel, Aluminum, Copper, Bronze etc. There are two basic types of chrome plating: hard chrome plating and thin dense chrome plating. Immersion into chrome plating tank Chromic Acid Insoluble lead alloy anode Part acts as the cathode Plating rate of 0.001” per hour 2015 FSRUGįinish Grinding Excellent dimensional control Tolerances as tight as +/ ” are achievable 2015 FSRUG Water, alcohol, grease, fats or aliphatic hydrocarbons have no effect on them. They possess extreme chemical inertness and are unaffected by alkalis, oxidizing agents and most inorganic acids. Lacquers, foils, tapes & waxes 2015 FSRUG The resins which the speaker has found to be of utmost importance especially in the field of 'hard' chromium plating are the 'Vinylite' co-polymer resins. Prep Machining (typically 0.004”-0.005” per side) Surface cleaning/polishing “Stop-off” of surfaces that are not to be plated.
0 Comments
Leave a Reply. |
AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |