Hard Chrome plating services
Hard chromium deposits are widely used for the provision of hard, abrasion resistant wearing surfaces and for building up of undersized and work parts. The value of chromium for such purposes lies in its hardness resistance to abrasion, passivity of surface and its anti-seize properties when applied to rotating or reciprocating parts. The deposits are thicker and are generally applied directly to basis metal without any pre coating.
Finishing of hard chrome plating parts are very critical. Articles that have a dull deposit and have not subsequently to be ground may be polished applied to a fast cutting white calico mop revolving at a surface speed of 41 to 46 m/s (8,000 to 9,000 ft./min)
Special techniques used in printing application
Chromium facing is extensively applied for the facing of printing-plates and cylinders. It provides a hard-wearing, corrosion resistant surface, which not only enables much longer printing runs to be obtained, but also permits the use of a wider range of printing inks. On chromium faced surfaces, inks can be used which would be unsatisfactory with plain copper owing to the possibility of change in tone value. Chromium facing is thus particularly advantageous in color printing and enables the length of run to be increased by 8 to 10 times as compared with a similar unplanted copper plate or cylinder. Using chromium faced photogravure cylinders on paper, a printing run of over 1,000,000 is quite normal, and it is by no means unusual to obtain as many
as 5,000,000 impressions before the highlights are lost. Wear takes place on the chromium deposit, the etching or engraving of the copper being unaffected. For some printing applications such as packaging and textiles, it may therefore be possible to chrome strip and re-chrome a cylinder face a number of times with a corresponding increase in the life of the etching.
HARD CHROME PLATING THICKNESS
It is generally accepted that thickness of 0.3mm to 0.4mm of chromium is the maximum practical limit for any purpose
Hardchrome plating uses
Hard chrome plating is widely used for facing gauges and the deposit which normally has a hardness of between 800 and 900 H.V has proved ideal
components such as piston rings and cylinder liners, crankshafts for marine and aero engines, bearings, hydraulic and Hardchrome rods are deposited with a thickness of 0.12mm as standard procedure to improve their wearing qualities and to resist corrosion.
Hardchrome deposition are applied to cutting tools generally from 5 to 12 microns.