» . E . B R ° v f % Editor» STKC Associate
C O N T R IB U T IN G to increasing a p p li
cation of m echanically-operated brushes b y th e steelm aking an d m etalw orking in
d ustries are developm ents in design an d fab ricatio n w hich p e rm it brushes to fu n c tion as an in teg ral p a rt or fixture of au to m atic m achines to w hich th e y are a t
tach e d . F lexibility, w ith in terch an g eab le a n d rep lacem en t featu res, has been a t
ta in e d to a m arked degree. M ore uniform p ro d u ctio n , low er m ain ten an ce, re d u c e d o p eratin g costs a n d sim plification of m a
c h in e design a re n o tew o rth y in d u strial b ru sh im provem ents.
B rushes are p rim arily tools fo r cleaning m etals an d m aterials; autom atic brushing is in m ost instances an auxiliary o p era
tion a n d an im p o rtan t one. N ot b ein g
auxiliary, autom atic featu res are desirable a n d w idely u sed fo r a m ultiplicity of cleaning work. F o r m achine brushes, a p e rm a n e n t m etal core on w hich is w ound steel-gripped b ru sh filler strips has re
placed m an y w ooden cores, elim inating w arpage a n d splitting.
T h e In d u strial D ivision of the F u lle r B rush C o., H artfo rd , C onn., form ing n a r
row steel strip a n d w ire in special roll form ing m achine, rolls b ru sh m aterial u n d er heavy pressure into a continuous b ack
ing strip w hich m ay b e sh ap ed to any core or flange fo r m achine app licatio n — cylindrical, spiral, circular, curv ed or flat.
B acking m e ta l is ru stp ro o f an d can b e p ro d u ced in any length, feeding a u to m atically from form ing m achine to core
w inding unit. T his brush construction is know n as F u llerg rip t.
A ttachm ents for adjustm ents to m a
chines are sim ple a n d rep lacem en t brush strips are easily installed. Strips can be radially coiled on m etal cores in close or o pen form ation, d e p en d in g on th e density of th e b ru sh re q u ire d ; m an y b ru sh filler m aterials, in clu d in g steel a n d bronze wire, h air or fibre, selected for any specific re
quirem ent, m ay b e fo rm ed in th e continu
ous strip. W hen th e b ru sh surface is worn dow n, cores are rew ound. F a u lty b ru sh ing, often cau sed b y loose b ru sh filler getting on w ork, is elim inated b y th e high pressure u n d e r w hich th e steel strip and w ire is fo ld ed a n d clam ped, creatin g a secure vise-like filler setting. Also set in
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a continuous strip a n d not in tu fts, the steel-backed b ru sh tends to w ear m ore uniformly in m an y operations.
D uctility an d elongation are prim e requisites in strip an d w ire used in fa b ri
cation a n d assem bly of backing; tests re
quire steel b e d o u b le d an d fo ld ed on its own diam eter against th e grain structure.
For b acking strips an electrogalvanized cokl-rolled soft steel w ith N o. 4 tem p er and edge hardness of 45-55 rockw ell, is generally specified for sta n d a rd re q u ire ments.
Round w ire in th e b ase of th e steel grip is also electrogalvanized, bru sh q u al
ity, freq u en tly No. 19 gage, a lth o u g h No.
16 an d No. 14 sizes are also u sed in numerous assem blies. Also for tw isted
Figs. 1 - 3— T hese unusual photographs ta ken in a large m id w estern steel m ill sh o w strip entering th e scrubber o f a continuous strip m ill (F ig . 1 ) and leaving tjie scrubber (F ig . 2 ) . In Fig. 3, a brush has ju st b een installed and
is ready fo r use
Fig. 4— Pair o f 5-inch tam pico'-filled brushes here are show n cleaning strip.
Bristles in strip fo rm are m o u n te d on a cadm ium -coated cast iron fla n g ed roll
Fig. 5— Brush filler strip form ing m achine w ith steel strip reel in rear, show ing contact w ith filler m aterial and steel w ire base a t closing toll
Fig- 6— T h is cylindrical sheet and strip m ill scrubbing brush is nearing co m p letion in th e plant o f th e F uller Brush Co. T h e filled strip is fe d directly fro m a fo rm in g u n it like th e one show n in Fig. 5. Core length o f th is brush is 120 inches; w e ig h t 500 pounds; finished brush len g th 75 inches and finished
fo r th is brush
w ire applications this g rad e is som etim es specified; too h ard filler w ire m ig h t scratch th e m etal finish in som e operations. This w ire can be w rap p ed around its own diam eter.
C adm ium -coated b acking m aterial is used in som e cases fo r im proved finish, b u t m ost m aterial is electrogalvanized before form ing. Sm allest flat coil u sed is
% -inch w id e a n d 0.030-inch in thickness, ran g in g to % -inch w ide b y 0.050-inch;
experim ental strips are b ein g fo rm ed of m aterial iy4-inch by 0.0625. H ow ever, steel as thin as 0.025 is form ed for som e units, g age of m aterial d ep en d in g on a p plications.
F o r filler m aterial, crim p ed u n tem p ered h ig h carbon steel w ire, in diam eters 0.003 to 0.0 2 0-inch a re u sed fo r som e p o w er brushes, also nickel silver fo r cleaning alum inum utensils. P hosphor bronze, brass, M onel m e ta l a n d stainless w ire are also used as fillers, th e la tte r tw o in chem ical a n d brass industries. Stainless steel fillers are used fo r scale rem oval after pick lin g operations.
B ronze w ire as filler m aterial, or m ixed w ith h air a n d fiber, con trib u tes m aterially to w ard elim ination of static, n o tab ly in th e leath er tan n in g in d u stry w h ere pow er b rushes are w idely used. H ow ever, clean
ing, a n d n o t static reduction, is the prim ary p urpose. Bronze filler is also su c
cessfully used on brushes to rem ove scale from saw blades a fte r pickling.
M ost cores fo r refills are steel cylinders, m any being seam less tubing. O th er as
sem blies are sheared backing strip, screw a tta c h e d to cast iron flange-ends, th e la t
te r freq u en tly plated . Cores u sed for brushes in th e food in d u stry are. generally alum inum w ith o th er m aterials b ein g con
sid ered fo r p o stw ar use.
A tam pico-filled b ru sh w id ely used in the steel ind u stry for sh eet sc ru b b in g and finishing operations is w ound on a 4%- inch O D seam less steel tu b e. F e d from a reel, n arrow fiat steel from w hich th e backing strip is form ed, first passes through tw o stam p in g a n d straig h ten in g rolls w hich also m ark identification sym bols on d ie m etal. T w o form ing rolls th en engage th e steel strip a n d sh ap e it into a rough U. A large disk a n d chain assem bly just beyond th e first form rolls, controls a hy d rau lic feed from th e filler from a reel a t rig h t angle to th e w ork, h o p p e r directly above. A ro u n d w ire, also from a reel a t rig h t an g le to th e w ork, is autom atically fe d into th e base of th e partially form ed b acking strip on to p of th e filling m aterial. Im m ed iately beyond
th e disk a n d m eshed closely to d ie rate of filler deposit a n d w ire feed, closing rolls press th e steel a t th e to p of th e U- channel, clam ping d ie filler into th e m etal, w ith th e w ire a t th e base d g h d y gripping the filler m aterial also. T h is m ay be seen in F ig . 5.
Closing pressures vary w ith types of brushes, size an d o perational speeds, b u t are sufficiently h ig h in all cases to firmly set a n d retain the filler in th e backing strip. B eads at th e to p ed g e of th e backing strip also a id in g rip p in g die-filler. W ire is straig h ten ed as it enters th e backing ch an n el over a grooved shoe or w heel. The finished steel h o ld in g strip is a modified triangle in m ost cases, b u t oval a n d flat sh ap es can b e ob tain ed w ith different closing rolls.
F ille d strip is d isch arg ed continuously th ro u g h a g u id e on th e form ing roll m a
chine, b u t can b e sh eared a t an y point, autom atically sealed a t th e ends to fit any core, special design or w id th . F ille d back
ing strip m ay also b e fa b ric a te d in a single length, 4 00 fe e t or m ore. S trip is fed d irect to d ie w in d in g m achine and w ound spirally to th e core fo r cylindrical brushes; num erous types u sed in tin mills a n d o th er cleaning operations re q u ire from 165 to 40 0 fe e t of fa b ric a te d strip filler for coiling a com p leted b ru sh . F irst tw o coils an d th e la st tw o are usually w eld ed to the core, securing th e strip a t th e b ru sh ends.
F lexibility of th is ty p e of b ru sh as
sem bly necessitates num erous refinem ents a n d variations fo r specific applications, b u t in general p ra c tic e d escribed is basic for b acking strip fabrication. T o m eet som e req u irem en ts o th er types of m etal m ay b e used, M onel b acking a n d center w ire fo r b rushes in th e brass in d u stry for som e operations. F o r w in d in g on small
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Fig. 7— S h o w n here are som e of th e various ty p e s o f brushes and A — Part o f 230-foot d rip ready fo r w in d in g core su ch as th e one show n w h ic h is 60 inches long and 4Vz inches in diam eter. Strip is w o u n d in spiral form ation as sh o w n at C to fo rm a condensed
brush ( D ) 54 inches long and 10 inches in diam eter. A t E is cross section o f brush strip sh ow ing m e th o d o f construction.
F is m id d lin g rem oval brush used tw o
V T E E L
iSISiSII
pany s experience in successfully solving this problem . W h en th e h acksaw m an necessary controls such as pyrom eters, floscopes, fire traps, au to m atic valves,n ectin g p ip e to the furnace, since it is com bustion to com plete cracking.
“C o m p lete com bustion occurs w hen
D isks above dem onstrate progres
sive steps in cleaning process.
R eading fro m to p to b ottom : D isk as forged; a fte r pickling; as black
en ed in bath; d isk w ith silvery color resulting fr o m stripping
b la cke n ed w ork in H C l solution By E. H. J O H N S T O N
Chief Metallurgist Stand ard Forgings Corp.,
C hicago
D U E to rigid M agnaflux specifications on seam s, nonm etallic inclusions, an d other defects on certain sm all aircraft an d engine forgings m a d e a t S tan d ard F o rg ings C orp., it w as fo u n d necessary to d e velop a cleaning m eth o d w hich w ould provide n o t only a surface free of scale, but one w hich w o u ld h av e a clear, b rig h t surface upon w hich th e red or black M ag- naflux pow ders w ould stan d clearly in r e lief.
This is especially necessary w hen a d e fect of very m in u te or shallow n atu re is present. T h e surface ob tain ed from th e routine su lp h u ric acid pickle has a te n d ency to b e dull a n d som etim es red d ish in color, especially if th e pieces are allow ed to stand an ap p reciab le len g th of tim e b e fore inspection.
Since the tonnage involved in these forgings d id n o t w a rra n t th e a d d itio n of a more expensive cleaning process to re
move th e scale an d p ro d u ce a b rig h t sur
face, it was d ecid e d to experim ent w ith a process w hich could be ap p lied to th e forgings after they h a d b een th ro u g h the routine su lp h u ric acid pickle.
After various acid m ixtures w ere tried without th e .desired results, it w as de
cided to try oxidizing th e surface m etal and sm ut w ith a strong solution of sodium hydroxide co ntaining n itrate. I t was known th a t this m ixture, w h en ap p lied to a piece of steel not too h ig h ly alloyed, will give a very black surface. I t w as found b y experim ent th a t this black oxidized su rface can be rem oved instantly by d ip p in g th e piece into a I to 1 solu
tion of hydrochloric acid. A ny of the common m ineral acids w ill rem ove th e black coating, b u t hydrochloric w as d e cided upon because it is som ew hat less dangerous to operators a n d gives off less fumes.
After th e b lack surface oxide has b een removed, th e forgings are w ashed in hot water a n d allow ed to dry. T h e resulting finish is clean a n d alm ost as w h ite as a piece of p a p e r. T h is provides a surface ideal fo r a re d o r black M agnaflux pow der.
Many sm all d efects w hich previously w ere unseen becom e a p p a re n t to th e u n aid ed eye.
T he fo u r solution tanks u sed in th e process are m a d e o f Vs-inch steel plates,
w eld ed together, an d can be of any size sufficient to p ro d u ce the req u ired n um ber of pieces p e r hour. Solutions w ere used in th e follow ing order:
T an k N o. 1— Black b ath . This solution is m a d e u p a n d u sed according to d ata received from E . F. H o u g h to n & Co. T h e p rescrib ed te m p e ra tu re o f 290-295 d e grees F a h r. is m ain tain ed a t all tim es, w ith steam coils in th e solution W ate r or ad d itio n al salt is a d d e d from tim e to tim e in ord er to m ain tain th e bo il
in g p o in t as recom m ended. As stated by H oughton com pany, the actual boiling p o in t o b tain ed in th e tan k a t an y tim e is the b est indication of th e condition of the solution. T h e color o b tain ed on the w ork is also a good indication. T h e pieces should alw ays com e out a je t black- color. (N o te accom panying illustration a n d disk th ird from to p ) .
T an k N o. 2— Plot w ater containing a sm all p ercen tag e of th e special blackener.
T an k N o. 3— H ydrochloric acid (1 to 1 ). T his solution g radually heats up som ew hat from th e h o t w ork being placed into it.
T an k N o. 4— H o t w ater. Sam e as tank N o. 2. T his tank can b e elim inated an d tank N o. 2 can be u sed tw ice.
Process consists of im m ersing th e work- in th e h o t w a te r tan k fo r 5 m inutes so th a t th e tem p eratu re lost in the blacken
ing tan k w ill be sm all. A fter 5 m inutes in th e h o t w ater, th e w ork is p la c e d in th e black en in g solution for 15 m inutes.
At th e en d of this tim e th e w ork is r e m oved, d ip p e d in h o t w a te r lan k No. 2 to rem ove excess caustic, th en into acid tan k N o. 3, a n d th en in to h o t w ater tank No. 4. T h e pieces are allow ed to rem ain in th e h o t w ater tan k fo r a b o u t 1 m in u te so they w ill b e hot enough to dry quickly in th e air. If n o t w h ite enough to suit, the process can b e rep eated .
Since th e installation of this process, visual a n d M agnaflux inspection on the sm all p a rts m entioned has b een step p ed up 100 p e r cent. N o t only does th e p ro c ess w ork very w ell fo r sm all forgings, b u t it can b e ap p lied to forgings or castings of any size. I t lias b een fo u n d th e surface condition o b tain ed persists fo r several m onths if th e pieces are k ep t in a dry, w arm nlaee.
May 21, 1945
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