Looking Back
10 YEARS AGO — June 18, 1998
New treatment hardens
chain drives: A new thermochemical
process developed
by Sedis, a French company,
increases the hardness of industrial
drive chains and makes them more
wear resistant. The
process boosts surface
hardness from about 800
to 1,900 Vickers and is similar to
chrome hardening: Atomic chromium
combines with the steel to
form a surface integral with that of
the pin. This prevents flaking, a risk
with electrolytic chrome plating. The
high temperature diffusion process
(around 1,832°F) produces uniformly
thick surfaces which adhere closely
to the substrate. The surface itself is a
complex chromized coating primarily
of extremely hard chrome carbide.
30 YEARS AGO
June 22, 1978
Additives silences squeal and stops
fade in asbestos-free brake pads:
Lubolid, by Dow Corning Corp., is
a new friction-control additive that
reduces
squeal, fade,
chatter, and
cold-start
sensitivity in
disc brakes.
With the
elimination
of asbestos
and an increase in the use of highperformance
disc brakes, frictionmaterial
manufacturers needed a replacement.
Dow Researchers found
that the physical properties of friction
materials could be modified selectively
by blending various solids
in specific concentrations. Further
development led to the Lubolid additive,
an inorganic gray powder, stable
to at least 500°C for disc-brake pads.
50 YEARS AGO
June 26, 1958
Oil or gas, or a combination of both,
can be used as fuel in this pressurized-
furnace steam generator. The
unit, from Babcock & Wilcox Co., is
designed for power, process, or heating
loads requiring steam capacities
to 400,000 lb/hr.
An integral combustion
air duct
on top of the unit
conserves space.
At left center is
the drainable superheater,
which
permits water
draining after a boiler shutdown.
Burners at extreme right are centralized
for easy observation and adjustment.