Magnesium housings … vauum impregnated

V A C U U M

Classified A b s t r a c t s

0

0

I - - G e n e r a l S c i e n c e a n d E n g i n e e r i n g - - I Contd.

m e t h o d s of ana lys ing t he ex t r ac t ed gases. The first p a r t of t he art icle is sub-d iv ided into m e t h o d s of e x t r a c t i n g oxygen, h y d r o g e n ,and ni t rogen. Deta i l s are g iven of t he oxygen ex t r ac t i on m e t h o d developed by Chaud ron and Moreau, S loman ' s a p p a r a t u s and C h a u s s a i n ' s a p p a r a t u s . The m a i n fea ture of all these m e t h o d s is t h a t t he steel is hea t ed to a t e m p e r a t u r e of 1,600°C unde r v a c u u m at which t e m p e r a t u r e i t is k n o w n t h a t all oxides are comple te ly reduced. H y d r o g e n p re sen t in steel is no t chemica l ly combined w i th t he me ta l ; i t s ex t r ac t i on can be effected in va r ious ways : (a) B y vo lumet r i c m e a s u r e m e n t of t he h y d r o g e n l iberated a t o rd ina ry t e m p e r a t u r e , (b) b y app ly ing a h e a t of 1050°C unde r v a c u u m , (c) b y v a c u u m fus ion a t h igh t e m p e r a t u r e , (d) b y ion b o m b a r d - men t , (e) by h e a t t r e a t m e n t a t c o m p a r a t i v e l y low t e m p e r a t u r e s ( app rox ima te ly 600°C). Methods based on t he l a t t e r have been developed by Newell, Cotbeck and Craven and Bas t ien . A shor t descr ip t ion of each of these m e t h o d s is given. Ni t rogen con t en t can be de t e rmined b y t he v a c u u m fus ion m e t h o d b u t in t he opinion of t he a u t h o r chemical m e t h o d s such as t he one devised b y Rocque t -Ole t t e give be t t e r resul ts . I n t he second pa r t of t he art icle t he a u t h o r gives a shor t descr ip t ion of t h e folIowing m e t h o d s avai lable for t he analys is of ex t r ac t ed gases : The a p p a r a t u s proposed b y L ebeau and Damiens , Podbie ln iack ' s me thod , the N a s h me thod , and t he mass spec t romete r me t hod .

Sommaire : L ' a u t e u r ddcrit t o u t d ' abo rd les appare i l s uti l is4s pour l ' ex t rac t ion des di f f4rents gaz : oxygene hydrog6ne , azote. I1 4tudie ensu i te Ies disposi t i fs ana ly seu r s

I6 Per Cent A l u m i n i u m - I r o n Alloy Cold Rolled in the Order- -Disorder Temperature R a n g e

United States. The a l u m i n i u m - i r o n al loys are k n o w n to have sound m a g n e t i c proper t ies and require no ma te r i a l s in cri t ical supp l y for thei r p roduc t ion . B u t the i r deve lopmen t is r e t a rded because in fabr ica t ion these ma te r i a l s show grea t br i t t leness . This appl ies in pa r t i cu la r to t he 16% a lumin ium- i ron alloy. The p re sen t art icle repor t s deta i ls of a series of exper imen t s , in t he course of wh ich 16% a lumin ium- i ron al loy wi th good duc t i l i ty and sound m a g n e t i c proper t ies was p roduced and fabr ica ted successfully. For t he p roduc t ion of t he ma te r i a l e lectrolyt ic iron was mel ted in a m a g n e s i u m oxide crucible in a p r e s s u r e - v a c u u m furnace of 30 lb capac i ty . The pressure a t t he s t a r t of t he me l t i ng was 200/z b u t rose in t he course of me l t i ng due to t h e l ibera t ion of gasas. The mol t en i ron was decarbur i sed wi th wet h y d r o g e n and s u b s e q u e n t l y deoxidised wi th d ry h y d r o g e n On comple t ion of t h e h y d r o g e n t r e a t m e n t t he h y d r o g e n was pu rged f rom the c h a m b e r wi th pure d ry he l ium, followed b y evacua t i on of the fu rnace to r emove h y d r o g e n dissolved in t he melt . The a l u m i n i u m was added to t h e m e l t af ter re - f i l l ing the fu rnace wi th hel ium. The m a t e r i a l w a s cas t into ingots of the d imens ions 1 0 × 5 × 1 inch. The first fabr ica t ion process was hot-rol l ing. The t e m p e r a t u r e Was 1,000°C and t he hea t was applied to t he slab one hou r pr ior to t he s t a r t of t he rolling process. This t e m p e r a t u r e p romo te s the fo rma t ion of large grains in t he mater ia l . Hot - ro l l ing was con t inued down to a th i ckness of 0.125 inch of the slab. The a l u m i n i u m - i ron phase d i a g r a m shows t h a t 10-20% of a l u m i n i u m alloyed to i ron t ends to order irito an FeaAI t ype latt ice. Consequen t ly i t was decided to h e a t - t r e a t and cool t he hot-rol led ma te r i a l appropr ia te ly and t h e n to cold-roll i t a t t h ree di f ferent t empe ra t u r e s , 500°C, 550°C and 575°C. The t e m p e r a t u r e of 575°C is j u s t above t he order

disorder t e m p e r a t u r e - r a n g e and ha s g iven t he m o s t sa t i s fac to ry resu l t s in t he exper iments . Cold roll ing a t 575°C can be con t inned down to a th i ckness of 0.007 inch. P h o t o m i c r o g r a p h s of t he end p roduc t show a h igh ly f ibred s t r uc tu r e ind ica t ive of t o u g h n e s s and duct i l i ty . .Special t e chn iques are described which faci l i tate fu r the r r educ t ion of th i ckness b y roil ing a t room t e m p e r a t u r e s down to 0.0005 inch th ickness . The m a g n e t i c proper t ies of cold-rolled 16% a l u m i n i u m - i r o n alloys af ter var ious h e a t t r e a t m e n t s are shown in a table pa r t l y reproduced below.

Magnetic Properties of Cold-Rolled 16 Percent All-Fe Alloys after Various Heat Treatments

~ e c i ~ e n

No.

i ; 9 7 -

1992X

2045

2045X

Thickness of laminations

0.014 inch

0.014 inch

0.007 inch

0.007 inch

/*2O

-~4~- 2778

412'7

4158

d.c. magneti~pr( ~m B2~

15 000 0.024

86 300 0.040

77 800 0.044

~erties

- - 3-;G-

4200

4000

4000

Bm b

7600

770

8000

Heat Treatment

FH to /,000°C--hold 2 hours. FC to 600°C---hold 10 minutes. RC FH to 900°C hold k hour. FC to 600°C--hold 10 minutes. Water quench FIt to 900°C--hold 1 hour. FC to 600°C--hold 10 minutes. Water quench FH to 1,000°C--hold 2 hours. FC to 600°C--hold 10 minutes. Water quench

FH--heated with furnace. FC--cooled with furnace. RC--withdrawn rapidly from heat gone to front of furnace. Sommaire : On donne des d6tails sur la p r6para t ion d ' u h alliage de fer et de 15% d ' a l u m i n i u m , qui est fai te duns u n four ~ v ide d ' u n e capaci t6 de 20 kg envi ron .

A Remarkab le E tch ing of Copper

See A b s t r a c t No. : 83 / I

M a g n e s i u m Hous ings . . . V a c u u m Impregnated

See A b s t r a c t No. : 77 / I I I

Abstract No. and References

Article by J. Amoignon

Le Vide 9, Jan. 1954

1462-1469

133/I

Article by J. F. Nachman &

W. J. Buehlcr J. APT1. Phys.

25, March 1954 307-313

134/I

135fl

April, 7954 Vacuum 229 Vol. I V No. 2