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Патент USA US2406539

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Patented Aug. 27, 1946
' Grover R. Greenslade, Scott Township, Allegheny
County, and Frederick K. Landgraf, Grafton,
Pa., assignors" to Flannery Bolt Company,
Bridgeville, Pa., a. corporation of Delaware
No Drawing. Application January 30, 1941,
Serial No. 376,600
2 Claims.
(Cl. 148—19)
This invention pertains to the manufacture of
staybolts, particularly the so-called ?exible
hollow staybolts and is for a method for the
manufacture of staybolts of the type having a
staybolts, have a case-hardened head. In the
case of a ?exible staybolt, the head is of .a spheri
cal form for cooperation with‘ a spherically
curved seat on the boiler plate and the case—
longitudinally extending telltale hole therein.
This application is a continuation-in-part of our
co-pending application Serial No. 322,950, {filed
hardening of the head of the bolt reduces wear
between the contacting surfaces. If the low
October 26, 1943, entitled “Hollow staybolts.”
melting point metal with which the interior of
Staybolts for use in boilers, particularly loco
the telltale hole is coated is applied before the
motive boilers, are commonly provided with a
carburizing or case-hardening process, the sub
longitudinally extending bore which is open at
sequent heating of the bolt to case-harden the
one end and which is closed at the other end of
head will melt the ?lm and destroy it. On the
the bolt but which extends throughout the great
other hand, if the head of the bolt is ?rst car
er portion of the length of the'bolt. This hole,
burlzed and then the hot coating is applied, the
which is known in the art as a telltale hole, isr 15 ‘subsequent heating of the bolt for the hot coat
for the purpose of indicating a fracture in the.
ing process is detrimental to the case-hardening.
bolt as is well understood by those skilled in the
The present invention provides a method by
March 8, 1940, now Patent No. 2,332,569 issued
The bolts are formed of a ferrous metal,
wrought iron usually being used.
means of which the coating of the telltale hole
Under the
may be accomplished ‘along with the case-hard
conditions of operation corrosion and oxidation '20 ening so that With‘the completion of one opera
tion the other is also completed. Moreover, the
and defeat its purpose. For the purpose of re
invention provides a method wherein the steps
tarding the oxidation of the metal copperplating
of carburizing and coatingthe interior of the tell
tale hole of the bolt may be practiced economi
of thetointerior
the fact
of that
the hole
is commonly
bolts are quite
.25 cally and rapidly. Our invention may be fully
in proportion to the diameter of the hole, the
understood by reference to the accompanying
take place in the hole, tending to close the hole
length of the bolts often exceeding 30 inches,
the limitations of space make the electroplating
of the interior of the hole with copper a di?icult
operation and there is no adequate Way for in
drawings, in which
bolt with a charge of vcoating metal therein and
" 30
specting the bolt after it has been plated to de
termine if the ?lm of copper is continuous.
Moreover, due to the presence of slag in the
metal in the surface of the wall forming the hole
the electrodeposition of the ?lm may not be con
tinuous as the copper is deposited only on metal
In our above-identi?ed co-pending ‘applica
tion we have disclosed a staybolt having an ap
plied coating" of a non-ferrous metal on the in
terior walls of the hole which coating is applied
to the interior of the hole in a molten state. An
alloy predominantly of lead, such as terne metal,
is preferably employed. This coating forms a_
continuous oxidation-resistant ?lm over the in
Figure 1 is a'vertical section through a stay
with a weighted rod on the charge for spreading
. the coating metal when the same melts and;
Figure 2_ is a view similar to Figure 1 showing
a. modi?ed arrangement in which a rod of coat
ing metal longer than the bolt is initially inserted
in the ‘bolt. ‘
In practicing the invention the staybolts, one
of which is shown in detail in Figure 1 and which
is designated A, is supported in an upright posi
tion with the head of the bolt down and With the
open end of the bolt up. The bolt is ?lled with a
liquid ?uxing agent, such as a solution of zinc
chloride. According to one preferred method of
practicing the invention, a cylindrical slug of '
coating metal designated B in Figure 1 is dropped
into the hole in the bolt, the slug of coating
terior of the hole notwithstanding the ‘possible
metal being of a diameter less than the diameter
presence of slag in the metal. If desired the
of the hole so that it will fall freely to the bot
coating thus formed may be covered in turn by
' tom of the hole. A wire ‘or rod 35 having a '
an electrolytically deposited ?lm of copper. The
weight 36 at its upper end is then placed in the
?lm of copper will be continuously deposited un 50 hole so as to rest on the top of its slug B. When
der the underlying coating of non-ferrous metal.
the bolt is heated up the slug of coating ‘metal
If for mechanical reasons the copperplating
B liqui?es and the weighted rod 35 sinks down
should not be continuous there is the added pro
through the molten metal displacing the molten
tection provided by the heat-applied metal coat
metal and forcing it upwardly around the tube
55 to the top of the hole. The slug B is preferably
hates the weighted rods but requires a greater
large enough so that there will be a slight excess
length of extruded metal. The excess metal is not
of molten metal running out of the top of the
lost as it is recovered when the bolt is tapped to
bolt. The rod is thereafter retained in the bolt
expel excess metal just before quenching, the ac
until the process has been completed.
After the bolts have been ?lled with flux and Ol cumulated excess metal being subsequently re
melted. Either method is satisfactory for the
after the slugs have been placed in them and.
purpose of accomplishing the invention. After
the weighted rods 35 have been put in place, the
the bolt has been terne-plated the removable ex
bolts are transferred to a basket in which they
tension 91 may be readily removed and placed on
remain during the heat treating process.
- ‘a
The bolts after being prepared in the manne 10 another bolt ,for .re-use.
After the bolts have been terne-plated or coated
described for treatment are loaded into one of
with alow melting point metal they may be elec
the baskets or carriers and ‘transported toa staf
tionary preheating furnace. The heads of they troplated onthe interior thereof in the usual way.
bolts are then immersed in the cyanide bath in a
furnace for the necessary length ‘of time.
After the bolts have been vcarburized and are
In some cases it may be desirable to reverse the.
process ‘and "electroplate the interior of the bolt
and then apply the terne coating, and my inven
moved to an unloading station the head ‘or ith‘e ~ ' . ltion contemplates such reversal of the process.
bolt should be quenched but the body of the bold
should be cooled gradually.
The metal referred to as terne coating metal
is ‘an ‘alloy of lead and tin in which the lead very
A'fter vthe bolts have been’in the quenching bath
cyanidin'g or vcase-hardening the ‘headofthe ébol‘t.
our method contemplates that from 't‘ne'initial
‘heating up of the bolts until the last heat-treat
"full of ‘metal during ‘theiprocess either by using
The operator transfers the bolts one at a time 20 greatly predominates. In lieu of terne coating
metal other soft or low point melting metals may
‘from ‘the ‘basket at the unloading stat-ion #to a
be used, vas, for example, lead or tin or ‘zinc or
basket at a quenching station. "ln'lso ‘doing he
various mixtures thereof. Under any circum
"removes ‘the weighted ‘rods 35-436 from the
stances the metal or alloy used for coating ‘the’
“bolt; inverts the “bolt andwtaps it against a solid
interior of the bolt should "be one which is not
surface; causing excess coating metal to be vex
melted at the temperature reached inside the
,j‘pelled from the hole in’ the bolt. He ‘then turns
boiler. Usually ametal or alloy of the class com
the bolt back to an inverted verticalposition and
prising ‘lead, ‘tin and ‘Zinc, "or ‘mixtures thereof,
sets ‘the ‘bolt "in one of "the holes of a carrier or
would be employed.
basket ‘and then ‘the heads of ‘the ‘bolts are
According to our ‘method ‘as herein described
quenched. "The bolts ‘may be in ‘the quenching
the spreading of the metal over the interior “of
ftanklfor some ‘time ‘before they are moved and
the hole to form ‘a coating is accomplished ‘with
‘during this time 'the‘stem's of the bolts cool gradu
same heating-up process that "is required for
for a su?icient "length ‘of "time they are hoisted 35 Excessive heating-flip of the bolt is thereby
avoided. ‘Moreover, since ‘the ‘hole ‘in the bolt is
. and .then lowered in a washing ‘bath.
the weighted ‘rod ‘as shown in Figure 1 or by using
ing operation and just ‘before the quenching of ' .40 ‘the extension "9! as ‘shown in'Fi‘gure 2, ‘the ‘coating
on ‘the interior of the ‘hole is not oxidized vor .in
the bolts ‘the holes Within the bolts ‘shall ‘be kept
vjtlrec'l. The heads 'o'f‘the bolts must remain in the
run ‘of boating metal and "this coating metal of
cyanide bath ‘a'pr'ede'terminedperiod of time and
should'be heated to a proper temperature
excess'lis expelled. One method of accomplish
‘ ' .ing' this .is that previously described and illus 45 before they ‘are carburized. A hoist which may
be intermittently operated in conjunction with
trated'in Figure 1.‘ Another way of ‘?lling the
the several stations provided for the heating up
holes 'in the bolts and maintaining an adequate
of ‘the bolts and the keeping of the bolts 'hot until
supply of meta1 therein is illustrated 'in'Figure 2‘.
the excess coating metal has been ejected there
.- ;In~this l?gure the bolt, also designated A, ‘has ‘a
.rod or coating .rnetal designated‘B’ inserted there 50 from and the bolt is ready .to be quenched pro
vides a convenient arrangement ‘for the prac
in. The rod of coating metal has a diameter
ticing-of the process. The capacity of the hoist
smaller than the diameter of the hole and in Fig
and of the preheating furnaces is increased’ by
ure:2 the .rodo'fcoating metal ismade longer than
io'ourse remains ‘in a molten condition ‘until the
the provision of auxiliary preheating stations.
ing metal projecting ‘beyond the end of the bolt 55 The provision of means for quenching the heads
‘of the bolts and permitting the bolts to cool im
cannot melt down and flow away the arrangement
' the .bolt. inorderthat the excess length-of coat-
shown in Figure 2 contemplates the use of ‘a re
mediately adjacent the loading and unloading
movable-extension '91 having a ?ange ‘9.2 which
embraces the upper end of. the bolt A and which
the carrier and the excess coating material ex
i has a hole therethrough that registers with the
hole in the bolt. ‘This extension 9! supports the
projecting upper end of the rod of coatingmate
station enables the bolts to be-quicklymovedfrom
pelled therefrom before 'it has a chance .to cool,
and enables the bolt to .be'quenched beforeitlhas
had an Opportunity to-cool. The separate wash
~ rial so that when the rod of coating material melts
ing operation is performed without .removing the
all ‘of the coating material will ?ow into the hole
in7the bolt. Because of the smaller diameter
of the coating ‘rod with relation to the diameter
of the hole» in the bolt it is necessary that the
bolts which have been quenched from'the carrier
in which they areplaced for quenching. flihisrar
rangement enables .the apparatus to be used :to “its
fullest capacity.
While we have illustrated and :describedcertain
rod of coating material initially be madelonger
speci?c apparatus for practicing :the method, :it
inorder to assure of the bolt being ?lled.
The method shown in Figure 1_ in which the 70 will ‘be understood ‘that various modi?cations and
changes may be made .in the apparatus within
‘weighted rods are used is more economical in that
less extruded metal is required than the method
shown in Figure 2 but expenses are involved in .
the provision and maintenance of the weighted
rods 3,6. j’I‘he' method shown in Figure 32 elimi
‘the contemplation of our invention and under the
scope of the following claims.
We claim:
l. The method of simultaneously coating ‘the
interior of hollow ferrous staybolts and carburiz
ing the heads thereof which comprises charging a
coating metal into the interior of the staybolt
and heating the staybolt to maintain the coating
metal ?uid, spreading the metal over the interior
of the staybolt by means of a metal rod entered
into the open end of the staybolt, carburizing the
head of the staybolt while said rod remains in the
staybolt, and thereafter removing the rod and i
2. The method of processing ferrous staybolts
which have one end closed and which have a tell
tale hole therein opening through the other'end
of the bolt which comprises setting the bolts up
right with, the closed end down and supplying a
charge of coating metal and flux to the interior
of the bolt, thereafter placing a rod in the open
end of the bolt and supporting it on the charge,
heating the bolt while maintaining it in an up
any excess coating metal which may be present 10 right position whereupon when said coating metal
in the bolt and rapidly cooling the bolt at a rate .{ is melted the said rod sinks through the molten
metal and forces it upwardly along the interior
su?icient to harden the head and freeze the coat- '
of the bolt, thereafter removing the rod and cool
ing metal before the coating metal sloughs off,
ing the bolt, the coating metal being a metal of
the coating metal being a solid at normal room ,
temperature and being molten at the temperature 15 the group consisting of lead, zinc, and tin‘ and
their mixtures.
of carburization, the bolts being maintained in an
upright position throughout the heating and car
burizing to prevent the coating metal from ?owing .1
out of the interiors of the bolts.
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