Year: 1887

page_text: Date of Application, 27th Apr., 1887
Complete Left, 27th Feb., 1888
Complete Accepted, 29th Mar., 1888
ROBERT ABBOTT HADFIELD Steel Manufacturer Sheffield Yorkshire do hereby
declare the nature of this invention to be as follows:-
This Invention relates to an improved process for hardening or toughening steel
or articles made of steel.
I make the articlo to be hardened or toughened either wholly or partially hollow
so that when heated it may be kept cool by a stream of cold water (or by equivalent
means) fed into the hollow portion as required-I then place the article in any
suitable furnace and heat it to the requisite degree; cold water being constantly fed
into the hollow portion to keep the interior of the article cool-1 then remove the
same from the furnace and immerse it in oil, water, or other suitable hardening
medium-By this improved process I harden or toughen the exterior of the article
to any required degree while at the same time I keep the interior thereof cool or
comparatively cool and thus materially if not entirely obviate any tendency therein
to subsequently fracture either from contraction or expansion or both.
SHIRLEY BOWDEN,
33, Southampton Buildings, Holborn, London,
Agent for the Applicant.

page_text: Articles Made of Steel.
I ROBERT ABBOTT HADFIELD Steel Manufacturer Sheffield Yorkshire do
hereby declare the nature of this invention and in what manner the same is to
bo performed, to be particularly described and ascertained in and by the following
statement:-
This Invention relates to an improved process for hardening or toughening steel
or articles made of steel.
To carry out my invention I make the article hollow or partially hollow by
forming a hole therein which extends either partly or entirely through it. Such
hole may be round taper or of any other convenient shape and depth-The object of
so piercing the article is to allow of a stream or jet of cold water being fed into
the hole so as to keep the interior of the article cool when it is placed in the furnace
The water is fed from the outside through an outlet pipe through which it is led
preferably into the bottom of the article and thence into an outlet pipe which is placed
at the top thereof one or both ends of such article being closed in any convenient
manner.
This arrangement allows of the cold water being fed in and likewise of the water
when warm being conveyed away as required-I prefer to place the article in an
upright position in the furnace the cold water being constantly fed through it in order
to keep the interior thereof cool-After being heated the article is removed from the
furnace and immersed in oil water or other suitable hardening medium.
From the foregoing description it will be seen that the interior of the article will be
kept as cool as when it is first inserted or will only become lukewarm while the
exterior will be heated to any desired degree according to the temper of steel required
to be produced-Such improved process may be applied to any kind of steel for
hardening the same-It may also be applied to the treatment of mild steels which do
not require to be hardened but only to be toughened on their exterior-The part which
is hardened or toughened will of course be the external part and the depth of such
hardened or toughened surface or surfaces may be varied as desired according to the
degree of heat employed thus the higher the heat of the exterior the greater will be
the depth of the hardened surface-Likewise by heating the article with a "taper heat"
that is to say a dull red or black hot at the upper end and gradually increasing to a
bright or cherry red or higher heat at the other end the depth of the hardened
surface can be varied at will and while one end is made quite hard this hardness may
gradually taper down to a skin hardness or if desired to a soft condition there being
no abrupt junction of hard and soft material but a gradually tapering condition from
hardness to softness which is a most important and valuable advantage.
An essential feature of my invention is that it can be varied at the will of the
operator in a way that has hitherto been practically impossible without causing the

page_text: article to crack or clink as no matter what is the heat of the exterior I obtain by my
improved process the special and important advantage of always keeping the interior
cool and so greatly reduce whatever strains may arise when the actual dipping or
hardening process takes place.
Another advantage is that such process is applicable to articles of irregular form
which hitherto it has been impracticable to harden.
Instead of employing water in the manner hereinbefore described-I may charge
the hollow portion of the article with metal or material of low melting point such as
lead, or any easily fusible compound-By this means I can always regulate the heat of
the interior and so prevent injury thereto from expansion such as results when the
article is heated uniformly all over in the ordinary way.
I would here observe that I make no claim to immersing or dipping the steel or article
in oil water or other suitable hardening medium as hereinbefore described save in com-
bination with my said improved process for hardening or toughening the exterior
thereof in the manner herein before specified.
Having now particularly described and ascertained the nature of my said Inven-
tion, and in what manner the same is to be performed I declare that what 1
claim is
1. The improved process for hardening or toughening steel or articles made of steel
by means of water substantially in the manner and for the purposes hereinbefore
described.
2. Charging any hollow article made in steel with metal or material of low melting
point such as lead or any easily fusible compound to prevent injury from expansion
substantially as hereinbefore described.
Dated this 27th day of February 1888.
SHIRLEY BOWDEN,
33, Southampton Buildings, Holborn, London,
Agent for the Applicant.