BBBBflt] «BlJIUrIrlr - Clpdigital.org

2112 Forging S tamping - Heat Treating
Jime, 1925
C h r o m e S u r f a c e s Electrolytically D e p o s i t e d
Chromium Plating Will Afford the Manufacturer an Opportunity
to Discard High Priced Alloys Where Resistance to
FOLLOWING the development of the electrolytic
method by which rare ancient bronzes, corroded
beyond recognition, are now being restored to
their original form, the research engineers of the
Chemical Treatment Company have perfected commercially
a process for chromium plating.
The commercial development of chromium plating
offers an opportunity for industry as a whole to utilize
the invaluable properties of metallic chromium in
a thousand different ways that heretofore have not
been possible.
The use of small percentages of chromium to produce
stainless or rustless steel alloys and extremely
hard chrome steels is well known. The advantages of
using chromium as a metal sheath or coating on other
metals as a protection against heat and corrosion, and
to greatly increase surface wearing qualities, have
long been apparent.
In appearance, a chromium plated surface may be
dull gray or have a silver luster, or have a polish much
more brilliant than nickel with practically the same
reflecting power as a high-grade mirror. As the surface
will not tarnish or corrode, no polishing is evei
required and it will outlast indefinitely all similar
surfaces.
The first factory for the production of chromium
plate has been in operation for several months and
thousands of steel, iron, brass and copper articles
have been produced for commercial use.
Crodon, the trade name under which chromium
plate is being produced, has been developed by Dr.
Fink for the Chemical Treatment Company, Inc., 26
Broadway, New York City, and is but one of the products
in the chemical and metallurgical field which
that companv has perfected or is developing.
Crodon will, in thousands of cases, afford the
manufacturer an opportunity to discard the highpriced
alloys which are so difficult to machine and
permit him to fabricate his product of more easily
worked metals, and still secure the necessary noncorrosive,
hard and attractive surface qualities by
applying a Crodon surface coating.
Heat, Corrosion and Wear Are Desired
By COLIN G. FINK,* Ph.D.
cations for chromium plate. The hardness, wear resistance,
corrosion resistance and permanent nontarnishing
attractive appearance of Crodon will give
the solution to many of the problems of the metal
industries.
A steel steam valve seat plated with chromium
and tested under 190 lbs. of superheated steam, first
passed through aluminum sulphate crystals to give
the maximum corrosive effect, has withstood a test of
200 hours, part of the test being run with the valve
practically closed to obtain the maximum wire-drawing
effect without affecting the valve seat. This means
that valves and seats can both be made of a steel
having the same coefficient of expansion so that there
will be no buckling in the valve seat as is sometimes
the case when the seats are made of alloys.
Crodon is being used commercially for that portion
of steam soot cleaner elements exposed to boiler
gases and the direct impingement of the flames and
is giving very satisfactory results in that there is no
surface corrosion. A small test piece of steel pipe
plated with less than one-half mill of chromium withstood
a temperature of 2000 deg. F. for 24 hours without
affecting the plated surface in any way, although
the inside of this pipe, also subjected to the flame
gases, was corroded to such an extent that half its
thickness was eaten away. There is a real field for
Crodon in lengthening the life of turbine blades and
many other engine and pump parts and accessories
which are now subject to excessive wear and corrosion.
Chromium is highly resistant to all organic acids
and to nitric and sulphuric acids. Crodon ware will
resist corrosion indefinitely and can be heated to high
temperature without the scaling and pitting so
familiar with ordinary iron and copper ware. Machine
parts of chemical apparatus, made of ordinary
metals, can be protected by Crodon plate and made
to resist the corrosive action of a large variety of
chemical reagents, besides outlasting all other metals
in wearing qualities.
Crodon plated copper strips have been repeatedly
bent and twisted until the copper itself breaks, without
any peeling or flaking of the plate.
High temperature thermometer casings, golf club
heads, plumbing fixtures, table ware, steam soot In the hardware field, stainless steel is well known
cleaner parts, marine hardware, high pressure steam and when it is considered that this steel contains only
valve seats, surgical instruments, turbine blades, acid- 13 per cent of chromium, the corrosion-resistant propproof
containers, automobile parts and accessories, erties of a chromium plate will be immediately
headlight reflectors, micrometers, dies and crusher- apparent. The hardware trade, above all others, apballs,
are articles to which Crodon can be applied to preciates the deterioration of stock due to rust and
economic advantage, and the variety of objects men­ other corrosion and it is only necessary to look over
tioned is but an indication of the extent of the field any hardware catalog and find innumerable articles on
for chromium plate.
which Crodon can be used to advantage.
For manufacturers of machinery of all kinds, the Where appearance is not a factor, Crodon plate is
electrical field, railroads, farm implements and the most readily produced with a soft gray finish which
metal trades in general, there are innumerable appli- is attractive although entirely without brilliance.
•Division of Electro-Chemistry, Columbia University, Chromium plated files have retained their sharp
Xew York Citv.
cutting teeth indefintely while in stock in localities