FABRICATION OFMAGNET IRON FRAMEMAGNET IRON FRAME

& TRIM COILS

ByD. P. HAJRA

&D. ADAK, S. SINGH, S. C. SARKAR, S. K. DAS, Dr. R. K. BHANDARI

SALIENT POINTS OF THE MAGNET

• WEIGHT OF IRON : 80 TONNES

• SUPERCONDUCTING : 7 TONNES

: Ø3 M x 2.2 M •OVER ALL DIMENSION

SUPERCONDUCTING COIL WEIGHT WITH CRYOSTAT

: 7 TONNES

• TOTAL WEIGHT OF (6X13) 78 TRIM COILS

: 1 TONNE

NUMBER OF POLE TIPS 3• NUMBER OF POLE TIPS : 3

• POLE GAP BETWEEN HILL

: 32 mmHILL

• MAXIMUM FIELD : 5.5 TESLA

• FIELD REPEATIBILITY : < 10-3

4• FIELD QUALITY (δB/B) : <10-4

• CRITERIA FOR MAGNET IRON SELECTION

Field quality dictates the stringent requirement for Iron

Quality control of magnet ironAs per IS : 1875 ( AISI : 1020 )

• Chemical composition

Homogeneity

C 0.12 – 0.15% , Mn 0.21 – 0.25%Si 0.18%, S 0.007 – 0.017% max. P=0.005 - 0.010% max

0.1 -

Si th bill t i f l & t th• Since the billet size for pole cap & return path ring are very big in order of 90 T. Number of different heat of steel is required to be added.

• Uniformity in different heat are being

C 0.07% and other elements 0.1%

• Chemical composition has been checked byladle analysis and check analysis afterpouring.

FORGING BY 6000 T PRESS

• To achieve uniform physical homogeneity and graini t tiorientation.

• Max. equivalent flaw size specified 13 mm diameterFBH or 50% reduction of normal beam.

• U. T. has been specified as per ASTM A388 – 86 ( VT,LPT & UT ).• Tested in both axial scanning (DGS scale, 2MHz, 24g ( , ,mm dia probe) & angle beam for circumferential probe.• All 35 pieces of yoke family was tested by the UTexpert from AFD and found OK except one upper polecap This has been remade & found OK in UTcap. This has been remade & found OK in UT.

800 mm X 600 mmX3mm

200 mm

800 mm X 600 mmX3mmFlaw size

210 mm

UPPER POLE CAP REJECTED DUE TO LARGE FLAW AT CRITICAL ZONE

Flaw size 580 mm X 390 mmX3mm

Pole cap has been machined from 90 T billetPole cap has been machined from 90 T billet

And machine down to 40 T after proof machine

Ultrasonic Testing after proof machined pole cap

To minimise the energy loss & to increase the permeability acoarse grain of ASTM grain size no. 3-5 has been maintained.

HEAT TREATMENT FOR POLE CAP

950OC@ 50OC / hr

Temp

t0 C

jobFurnace

9500CJob size dependent

Temp

4/5/98 2/5/98 2/5/98 27/4/98 Time

G i i t l b di th t t t fi l

job

• Grain size control by guarding the temperature at final

forging operation & subsequent annealing.

• Final Forging at low temperature ,introduces some strain Final Forging at low temperature ,introduces some strain

lattice followed by high temperature annealing promotes

large grain structure.

• Proof machining produces strain surface to a considerable

depth and make the iron with high coersive intensity and

low permeability . Annealing at 700 O C is done to relief

the surface strain.

• Magnet should have a cylindrical

YOKE MACHINING

symmetry about it’s vertical axis

& mirror image symmetry w.r.t

median plane to achieve goodp g

axial focusing.

• All yoke individual structure

has been machined on VTBhas been machined on VTB

with the following tolerances

127 µ

• Surface finish on mating

250 µ

250 µ

faces are Ra 6.3 µ .

• Assembly tolerances has been

Controlled further by re machiningControlled further by re-machining

after stacking.

• 156 no’s of deep (635mm)

hole done with an accuracy of

+130 µ & 1 mm on axis.3 places

drill bit was broken.

LOWER POLE CAPLOWER POLE CAP•Machining and clamping was bit difficult because of softness of iron ( BHN 117) & heavy weight.

• Utmost care was taken during handling to prevent any damage.

DRILLING ON RETURN PATH RING ONA RADIAL DRILL MACHINE

POLE TIPS ASSEMBLY INSIDE MAGNET

• 254 No’s of jigs & fixtures have been made to control254 No s of jigs & fixtures have been made to controlthe close tolerances of pole tip family components.

• To achieve mirror image symmetry & 120o symmetrybetween upper and lower assembly.pp y

• All the components have been machined within thefollowing tolerances.

• 25 µ • S f fi i h R 1 6µ

25 µ• Surface finish Ra. 1.6 µ

• Assembly controlled within 165 µ

TURNING FIXTURE FOR POLE TIP

•The typical contour machining of pole tips were donesimultaneously on a fixture to achieve the same tolerancesfor both mirror image pole tip ( Upper & lower )

•INNER POLE TIPS MACHINING ISON PROGRESS ON VTB ON TURNINGFIXTUREFIXTURE.

• Outside diameter is being measured by micrometer

POLE BASE MACHINING ON CNC PLANOMILLING

•ALL THE HOLE, DEE-STEAM, TRIM COIL LEAD ETC.ON POLE BASE WAS DONE IN A CNC PLANO-MILLING

M difi ti h b d f ¾” UNC All b lt t M20• Modification has been done for ¾” UNC Allen bolt to M20 x2.5 to avoid puncture at counter bore.

POLE TIP FAMILY ASSEMBLY IS PROGRESSING

• Dowel pin has been provided with push fit ( H7 j6) forrepeatability of assemblyrepeatability of assembly.

• 3 Numbers of peripheral dowel pin ( ø 40 mm) on theyoke assembly has been provided for repeatability ofradial orientation.

VACUUM TESTING

Vacuum testing is on progress for central plug componentsVacuum testing is on progress for central plug componentsNumbers of welding has been done between SS to MS in thisassembly.

All th fl ld d ith l ( & l ) hAll the flanges welded with pole cap ( upper & lower) hasbeen tested under high vacuum of the order of 2 x 10 –7 torr.

All the vacuum sealing for trim coils leads on upper pole caphas been tested under high vacuum randomly.

MAGNET ASSEMBLY

1200 S & O AG AS1200 SYMMETRY & MIRROR IMAGE HAS BEENACHIVED BY FOUR TECHNOLOGICAL PLUG WITH ACLOSE TOLERENCE & INSURTED FROM TOP TO THEBOTTOM SURFACE OF THE ASSEMBLY AS PLUGGAUGEGAUGE

ASSEMBLY WITH UPPER POLE CAP IN CLOSED CONDITION

Magnet assembly with pole cap lifted position

Maximum lifting height of upper pole cap is 1143mm.

DRIVE SYSTEM FOR UPPER POLE CAP LIFTINGMOUNTED ON THE UPPER POLE CAP

LAYOUT AND INSTALLATION OF PIERS

C f i f i• Centre of the Magnet iron frame was located with help of two temporary fixture fabricated for this purpose.

• Both the center of the octagonal opening at vault floor hexagonal opening at basement has been matched withhexagonal opening at basement has been matched with the help of plum dropped from the fixture.

• The magnet 0 0orientation and beam line axis was laid down and marked on the vault floor. Also the pierdown and marked on the vault floor. Also the pier positions have been marked on pier foundation plate.

POSITIONING OF MAGNET w.r.t BEAM LINE

Beam lineMagnet Yoke

0 0 HILL

MAGNET ASSEMBLY WORK IN PROGRESS AT NEW BUILDING

MEDIAN PLANE

INSTALLATION OF MAGNET

RECTIFICATION DONE AT VECC

• Phase probe hole has been enlarged from ø16 to ø18

Shi f 1 thk h b• Shim of 1 mm thk. has been re-fixed on lower pole cap sector “C”.

• 1 mm thk. Shim has been fixed by TIGtag welding

FABRICATION & INSTALLATION OF PIER

• Three no’s of piers ( Length 5930mm)have been fabricated

from out side sources.

• Piers design has been

• O.D 219.07mm and 12.7mm thk SCH 80• Piers design has been

audited from safetypoint of view byusing EMRC-NISAprogramme and safety

thk. SCH 80 Seamless pipe

5930mm

p g yfactor found 1.97.

• Safety factor havebeen enhanced 31 times b idi h i t lby providing horizontalsupport at two differentheight from base (at 2400mm,5600mm)

• Three no’s of intermediate flanges of typical rectangular shape with a thickness 69 mm were fabricated for fixing magnet iron lower pole cap over piers. The designs of intermediate flange have been audited for safety point of view by using EMRC -NISA programs & safety factor achieved 2.65.

• Lower pole cap with intermediate flange have been• Lower pole cap with intermediate flange have been placed over piers top flange after leveling and fastened.

LOWER POLE CAP ASSEMBLY IN PROGRESSPROGRESS

669.90 max.

669.55 min.

• Leveling of the lower pole cap top surface has been checked byg p p p yoptical instrument. The leveling has been achieved a max randomvariation within 127-micron.

• The lower pole tips assemblies have been installed onto thelower pole cap. Leveling of the top surface of three pole tips havebeen checked & achieved a maximum random variation within150 micron.

LEVELING OF POLE TIP ASSEMBLY BY OPTICAL INSTRUMENT

L l l li h b d ithi 127• Lower pole cap leveling has be done within 127 µ max.

• Lower pole tip assembly leveling after installation on lowerpole cap has been achieved within 150 µ max.

TOPPLING DEVICE FOR POLE CAP ASSEMBLY

TOTAL NUMBERS OF COILS 78TRIM COILS FOR K-500

35 5+0.5

14.5+0.5-0.0

35.5 -0.0

+0.50-0.00

177.80.00

COIL MOUNTED OVER POLE TIPAFTER VACUUM IMPREGNATION

TRIM COIL WINDING MACHINETRIM COIL WINDING MACHINE FABRICATED IN VECC

TRIM COIL No - 12 & 13 AFTER WINDING

INNER POLE TIP WITH TRIM COIL BEFORE POTTING

INNER POLE TIP WITH TRIM COIL AFTER POTTING

PLANT FOR TRIM COIL VACUUM IMPREGNATION

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