s ta n d in g q u a litie s. I t re ta in s th e h ig h d ie lectric s tre n g th o f c o n v e n tio n a l enam el. I t is a t le a st th re e tim es to u g h e r an d m ore flexible a n d m u c h m ore re s is ta n t to ab ra sio n . I t show s no te n d e n c y to becom e b rittle , crack , a n d lose its to u g h n ess o n lo n g exposure to h e a t.
A n o th e r a d v a n ta g e o f F o rm ex en am el is t h a t i t is re s is ta n t to th e so lv e n ts used in th e tr e a tin g v a rn ish e s t h a t are a p p lie d to w in d in g assem blies.
T h in k w h a t j u s t th is one fe a tu re of th e new G -E d ire c
t-—___ c u rre n t m o to rs m eans! G re a te r a s s u r
ance o f c o n tin u o u s o p e ra tio n , few er re p a irs a n d re p la c e m en ts, low er co sts o f p ro d u c tio n . W h y n o t p la n now to g et th e se a d v a n ta g e s ? Y o u n eed only specify “ G -E D -C M o to r s ” in y o u r e q u ip m e n t o rd e r. O r, if y o u p refer, ta lk o v er y o u r re q u ire m e n ts w ith o u r n e a r
e st re p re s e n ta tiv e . G e n eral E le c tric C o m p a n y , S c h e n e c ta d y , N ew Y o rk . Ç THAN
g æ s g i
B E T H L E H E M S T E E L C O M P A N Y
f&agSBM
b£thiehem 5TÈEL I
84
/ T E E L
S p a r k T e s t i n g
■ CHARACTERISTICS of sp ark s generated by a grinding w heel have several ways of im p artin g in fo rm a
tion to the experienced operator.
One use is in classifying irons and steels. The accompanying c h a rt and table gives not only inform ation on the more fam iliar steels b u t also on some of the new er alloys and represents latest inform ation avail
able on this subject.
Spark characteristics are largely a function of oxidation of elem ents present in the specimen. T h u s pres
ence of carbon in th e iron leads to high-intensity sp u rts as th e carbon burns in the air a sh o rt distance away from the wheel. Som e soft nonferrous metals like copper and aluminum yield no tru e grinding sparks in air. P ractically no sp u rts appear from 19 p er cent tu n g sten high-speed steel — ap p aren tly they are inhibited by the tungsten. Die
steel w ith 5 p e r cent tu n g sten still yields explosive sparks.
W hile n eith er photographs nor sketches can convey a tru e picture of sp a rk s as seen by th e eye, they do help to classify an d illu strate pronounced differences. All colors tab u lated re fe r to streaks, not sp u rts. A fine rep e atin g sp u rt is one w hose branches explode several tim es—a form ation suggestive of a clum p of fine flower blossom s. A strik in g exam ple is provided by plain high-carbon steel.
L en g th of stre a m tab u lated here is from use of an A lundum 36-P wheel, 12 inches in diam eter, 1 inch thick, ru n n in g a t about 5000 s u r face feet p e r m inute. A portable g rin d er w ith a 6-inch wheel, IV*
F ro m “S p a rk s fro m G rin d in g ” by H. W.
W agner, re s e a rc h en g in eer, N o rto n Co., W o rcester, M ass.
inches thick, m ay be m ore conven
ient. In each case th e full len g th of th e stre a m should be exposed to th e view of th e inspector to ex
am ine both in itial and secondary de
tails of th e phenom enon. N ecessar
ily, experience and acquaintance w ith sp a rk s fro m m etals of know n com position a re necessary fo r re
liable judgm ent. T his judgm ent, however, is not a su b stitu te fo r exact chem ical analysis b u t m erely is a rapid, econom ical m ethod of se p a ra tin g and classifying types of irons and steels and som e nonfer
ro u s m etals.
Of th e new er alloys, high-speed steel is not easily m istaken w hen in spected by th e sp ark m ethod. Dull color n e a r the w heel and long length a re quite app aren t. M anganese steel, 8, yields a stre a m o f high brilliance.
Stainless steel could be confused w ith m achine steel b u t th e
staln-Metal v
1- W rought iron 2. Machine steel 3. Carbon tool steel
<• Gray cast iron 5. White c ast Iron 6- Annealed m all, iron
High speed steel 8. Manganese steel
“• Stainless steel
10. Tungsten-chrom tum die steel
11. Nitrided N itralloy 12- StelUte
14 *u n g s’;en c arb id e 1°' Copper. brass, a lu m in u m
R e la tiv e C olor of
L e n g th of S tre am C olor of
S tre am , Close S tre a k s N e a r Q u a n tity of N a tu re of jm e o f S tre a m In c h e s t to W heel E nd o f S tre a m S p u rts S p u rts
L a rg e 65 S tra w W hite V ery few F o rk e d
L a rg e 70 W hite W hite F ew F o rk e d
M o d erately la rg e 55 W hite W hite V ery m an y F ine, re p e a tin g
S m all 25 Red S tra w M any F ine, re p ea tin g !
V ery sm a ll 20 Red S tra w Few F ine, re p e a tin g 1
M o d erate 30 R ed S tra w M any F in e, re p e a tin g
S m all 60 Red S tra w E x tre m ely few F o rk e d
M o d e rately la rg e 45 W hite W h ite M any F ine, re p e a tin g
M o d erate 50 S tra w W h ite M oderate F o rk ed
S m a ll 35 Red S tra w * M any F in e, repeating'*
L a rg e (cu rv ed ) 55 W h ite W h ite M o d erate F o rk e d
V ery sm a ll 10 O ran g e O ran g e N one
E x tre m e ly sm a ll 2 L ig h t o ra n g e L ig h t O ran g e N one
■i-V ery sm all** 10 O ran g e O ran g e N one
N one N one
Erln(i:'niu,r,t:5„ obtained w ith 12-inch w h eel on b ench s ta n d an d a re w«eel, p ressu re, etc. ‘ B lu e-w h ite s p u rts . “ Som e w av y :re la tiv e
s tre a k s . only. A c tu al le n g th in e ac h in s ta n c e w ill v a r y w ith
November 4, 1940 85
pellets form ed from fused particles of iron and steel in the stre a m have been used to identify certain alloy steels.
Such pellets have distinct char
acteristics w hich provide fairly re
liable com parisons.
P i g I r o n , F e r r o a llo y A c t i v i t y O ff i n 1939
■ M an u factu rers of pig iron and ferroalloys reported m oderate de
creases in em ploym ent, w ages and production in 1939, com pared with 1937, according to prelim inary fig
u res’ of th e census of m anufactures fo r 1939, m ade by th e bu reau of the census.
F ig u res cover establishm ents en
gaged in m an u fa ctu re of pig iron and ferroalloys from ore and scrap, and castings m ade direct from the furnace. M anufacture of electric ferroalloys is included in the chem
icals industry.
Value of products in 1939 was
$550,802,313, a decrease of 18-1 per cent com pared w ith $672,525,407 in 1937. W age earn e rs prim arily en
gaged in m a n u factu rin g in 1939 num bered 19,537, a decrease of 15.3 per cent com pared w ith 23,07d re
p orted fo r 1937. W ages in 1939 to taled $28,312,336, w hich was 20.5 p er cent less th a n $38,001,438 paid in 1937. E stab lish m en ts engaged in this production in 1939 numbered 81; in ’37 they totaled 87.
E x p o r t F i r m O r g a n iz e d
■ A lberto Ubbelohde Inc., has been organized, w ith head q u arters at R ector street, New York, to serv a s th e A m erican affiliate of Albei Ubbelohde Com pania which has its h ea d q u a rte rs in Buenos Aires, Ar
gentina, and offices in Rosario, g en tin a, and Montevideo. Uruguay.
The new com pany also is a ^ iliate w ith F. C. Ubbelohde of L ondon and A ntw erp.
A t Buenos Aires, the U bbelohde com pany is an im p o rter of steel a various m etallurgical products rundries. At New York it expo - the sam e products. I t als0 P poses to create A m erican outlet fo r various products of Arge and U ruguay, fo r reciprocal red
sons. f
A lberto Ubbelohde is president oi th e new com pany. Jules Die ' ’ who long had been active in ma_
chine tool sales, and who n°
m an ag er of foreign sales foi b ersb u rg E ngineering Co., ^ ‘ bersburg, Pa., is vice president ; J. L an caster is secretary and t u re r. Mr. Dierckx and M r ^an ca ste r a re a t 2 R ector stie , York.
/ T E E L
less steel sp ark s are less brilliant in color n e a r th e w heel and the stre a m itself is thinner. D ifferent brands of stain less steels and irons yield sp a rk stream s w ith a wide divergence of volum e and color. The stream sketched in 9 is from a 12 to 14 p e r cent chrom ium low-car
bon type. T ungsten-chrom ium die steel, 10, differentiates itself from the cast irons by blue-white glows a t the sp u rt.
N itrided N itralloy, 11, exhibits one su rp risin g eccentricity. S parks n ear the wheel form w horls and some actually tu rn from the m ain line of travel by m uch over 90 degrees.
T he sam e tendency is exhibited to
a lesser ex ten t by m anganese steel and to a still lesser e x te n t by some o th e r steels.
Stellite, 12, and cem ented carbide, 13, in co n trast to th eir brilliant per
form ance as tools, provide drab fire
works. Line of travel is plain and short. T em p eratu re color from the carbide m aterial is slightly higher th a n from the stellite and the stre a m is extrem ely short. Nickel, 14, yields a sp a rk which a t first m ight be confused w ith the stellite spark. Close observation, however, will reveal a wavy m otion of som e of the nickel stre a k s while the ste l
lite s tre a k s a re all stra ig h t.
L ess spectacular th an sparks,
H a r n e s s e s U r a n i u m A t o m
— (1 By m eans of the above a p p ara
tus, 200,000,000 electron-volts of the sp lit uran iu m atom , U-235, w ere m ade to tu rn on the new 50,000- w att, air-cooled tra n sm itte r of W est- inghouse statio n WBZ, near Boston, recently.
The sp littin g action took place inside th e gleam ing polystyrene cham ber, rig h t, a t the top of which is a sm all piece of uranium . Dr.
W illiam E. Shoupp, research engi
neer, is holding a container in
which is a m ix tu re of rad iu m and beryllium covered w ith paraffin to provide a source of slow neutrons, o r atom ic bullats. The electric c u r
re n t produced by the sp lit u ran iu m atom w as pictured on the oscillo
g raph screen, low er rig h t, in the cabinet a t the left. The a p p aratu s w as designed by Dr. E. U. Condon, left, associate director of the com
pany's research laboratories. Cour
tesy W estinghouse E lectric & Mfg.
Co., E a s t P ittsb u rg h , Pa.
86