ELIMINATION OF HOLES FROM CRM-2 COILS

TEAM MEMBERS:ROHIT RANJAN ( TE SMS-2 )

SRINIVASAPERUMAL (TE HSM-2)SOUMI MANDAL (TE CRM-1)

ANMOL RATHI (TE CRM-2)

DEFECT DESCRIPTION

ROUND SHAPED HOLES

CONTINUOUS NAIL SHAPED HOLES

RUBBING MARKS DUE TO SLIVER

PROBLEMS DUE TO HOLES AT CRM-2

MAJOR PROBLEMS• PLTCM STRIP BREAKAGE.• 270-300 TONNES PRODUCTION

LOSS PER HOUR .• MATERIAL AND YIELD LOSS DUE

TO SALVAGING / DIVERSION.• DAMAGE RISK TO

EQUIPMENTS(LIKE ROLLS)• QUALITY LOSS• CUSTOMER DISSATISFACTION.

4

CAUSE AND EFFECT DIAGRAM FOR HOLES IN CRM COILS

HOLES

INCLUSION & CRACKS REMAINS

IN THE SLABS

MATERIALMACHINE

MEASUREMENT METHOD OTHERS

BLOW AND PIN HOLES IN SLABS

FOLLOW UP OF SOP

CHEMISTRY

GAUGE VARIATION IN

HSM AND CRM COILS

SCAB, SLIVER AND EDGE SLIVERS DEFECTS IN

HSM COILS

MAN

BURR AFTER TORCH CUTTING

FALLING OF FORIGN MATERIAL IN HR

(OR)CR COILS

IMPROPER DESCALING

ABNORMALITY SLABS

UNEVEN THICKNESS IN HSM

COILS

IMPROPER SCARFING

INCLUSIONSIMPROPER CLEANING OF

EXHAUST HOOD AND EQUIPMENT IN HSM

FAULT IN MANUAL SCARFING

DEPOSITION AT FUME EXHAUST HOOD IN HSM

ANALYSIS DRILL DOWN

DOWNSTREAM(CRM, HSM, SMS)

UPSTREAM(SMS, HSM , CRM)

• COLLECTION OF DATA CRM- HOLE INSTANCES AND BACKMAPPING THE DEFECT POSITION WRT TO HR COIL.

• HR COILS DEFECT IMAGES WERE SEEN IN PARSYTEC.

• COLLECTION OF SLAB REMARKS FOR THOSE DEFECTED COILS.

• CORELATING THE DEFECT POSITION IN HR COILS WITH WHAT OBSERVED BY BACK MAPPING FROM CRM-2 COILS AND WHAT OBSERVED IN PARSYTEC IMAGES.

• 181 TRIALS SLABS AND 15 AUTOSCAEFED SLABS WERE SELECTED FROM SMS-2 AND PROCESSED IN HSM-2.

• HR COILS DEFECT IMAGES SEEN IN PARSYTEC.

• IN CRM-II 153 COILS WERE PROCESSED TILL MARCH.

SEM ANALYSIS FOR HOLES IN CR COILS AND SCAB IN HR COILS

ROUTE WISE HOLE DATA ANALYSIS(FOUR MONTHS DATA CONSIDERED OF DECEMBER, JANUARY, FEBRUARY AND MARCH)

82

42

72

UNIT COUNT %HSM 1 167 46.6HSM 2 191 53.4

GRAND TOTAL 358

GRADEWISE ANALYSIS FOR FOUR MONTHS

PLOT SHOWS JVHC130N00, JVHC131NA0, JVHC210N00 ,JVHC120N00 IS MORE AFFECTED(THE CHART IS PLOTTED BASED ON HOLE DEFECT COILS GRADE )

GRADEWISE ANALYSIS WRT OVERALL PRODUCTION(FOR THREE MONTHS DEC,JAN,FEB )

ANALYSIS wrt OVERALL PRODUCTION SHOWS C130, C131 HAS THE HIGHEST PRODUCTION AMONG OTHERS.

JVHC13

1NA0

JVHC21

0N00

JVHC12

0N00

JVHC12

2NA0

JVHCIFFN00

JVHZ12

1NA0

JVHC22

0N00

JVHC23

0N00

JVHC21

0T00

JVHC12

1NA0

JVHC53

4N0S

JVHHIFFN00

JVHZ12

0N00

JVHC21

0NA0

JVHC33

9N00

0

20000

40000

60000

80000

100000

120000

0

2

4

6

8

10

12

PRODUCTION QTY. DEFECT QTY. % REJECTION % WRT. TOTAL PRODUCTION

GRADES ROLLED IN CRM2

QU

AN

TITY

(tons

)

PER

CE

NT

AG

E(%

)

GRADEWISE ANALYSIS WRT OVERALL PRODUCTION(FOR MONTH OF MARCH)

JVHC13

0N00

JVHC13

1NA0

JVHZ12

0NA0

JVHC12

1NA0

JVHC22

0N00

JVHCIFFN00

JVHC12

0NA0

JVHC21

0N00

JVHC23

0N00

JVHC21

0NA0

JVHC53

4N0S

JVHZ93

5N00

JVHC12

5N00

JVHC23

0N0F

JVHC23

1T0F

JVHC33

4T0F

JVHZ21

0T0F

JVHC23

0T0F

JVHC22

1T0F

0.0

10000.0

20000.0

30000.0

40000.0

50000.0

60000.0

0.0

10.0

20.0

30.0

40.0

50.0

TOTAL PRODUCTION DEFECT QTY(TONs) REJECTION % % wrt TO OVER ALL PRODUCTION

GRADES ROLLED IN CRM2

QUA

NTIT

Y(to

ns)

PER

CEN

TAG

E(%

)

ANALYSIS wrt OVERALL PRODUCTION SHOWS C130, C131 HAS THE HIGHEST PRODUCTION AMONG OTHERS.

THICKNESS WISE ANLYSIS IN CR COILS

0.2 0.4 0.6 0.8 1.0 1.2 1.4 1.6 1.8 2.0 2.20

100

200

300

400

500

600

700

800

THICKNESS VS POSITION OF DEFECT GRAPH

POSITION OF DEFECT AT HEAD END POSITION OF DEFECT AT TAIIL END

THICKNESS

PO

SIT

ION

OF

DE

FEC

T

MAXIMUM DEFECT LIES BETWEEN THICKNESS RANGE OF 0.5-1.0

OBSERVATIONS AT SMS FOR FOUR MONTHS

OK/NOT OK SLABS COUNT %NOT OK 61 32.28

OK 128 67.72TOTAL 189

OK/NOT OK SLABS ANALYSISSLAB REMARKS COUNT

AMLC Manual 1BOPS Alarms 3Cold Inspection 1Fly Tundish Slab 5High MLF 1High Stopper Variation 2Ladle Change Over Slab 22Ladle Change Over Slab Next 5Low Casting Speed 1Low Tundish Level 4Others 4SEN Lancing (TNC) 1Seq First Slab 3Seq Last Slab 1Speed Reduction (if >0.4 mts/min) 2Speed Reduction [If.0.4mts/min] 1Transition Slab 3Tundish Tube Change(TCD) 1Grand Total 61

NOT OK SLABS

SCARFED/NOT SCARFED COUNT %SCARFED 15 7.9NOT SCARFED 174 92.1Grand Total 189

• TABLE SHOWS DEFECT IS COMING FROM BOTH NORMAL AND ABNORMAL SLABS

OK- NO ABNORMILITY SLABS NOT OK- ABNORMILITY SLABS

SCARFING DETAILS:AUTO SCARFED = 1MANUAL SCARFED = 14

COUNT AT HEAD END= 110COUNT AT TAIL END = 9

DEFECT POSITION ANALYSIS AT HEAD END AND TAIL END IN CR COIL

(FOR FOUR MONTHS DECEMBER, JANUARY, FEBRUARY AND MARCH)

0 1000 2000 3000 4000 5000 6000 7000 80000

100

200

300

400

500

POSITION OF DEFECT at HEAD END(mtr)POSITION OF DEFECT at TAIL END (mtr)

CR COIL LENGTH

POSI

TIO

N O

F D

EFEC

T(H

EAD

END

AN

D TA

IL E

ND)

• THE SCATTER SHOWS MAXIMUM DEFECTS LIES AT HEAD END.

HSM-2 CRM-2

DEFECT POSITION ANALYSIS FROM MIDDLE IN CR COIL

DEFECT COUNT= 21

(FOR FOUR MONTHS DECEMBER, JANUARY, FEBRUARY AND MARCH)

HSM-2 CRM-2

DEFECT POSITION ANALYSIS AT HEAD END AND TAIL END IN CR COIL HSM-1 CRM-2

0 1000 2000 3000 4000 5000 6000 70000

100

200

300

400

500

600

700

POSITION OF THE DEFECT AT HEAD ENDPOSITION OF THE DEFECT AT TAIL END

CR COIL LENGTH

POSI

TIO

N O

F D

EFEC

T (A

T H

EAD

EN

D A

ND

TA

IL E

ND

)

COUNT AT HEAD END= 79COUNT AT TAIL END = 16

HSM-1 CRM-2

DEFECT POSITION ANALYSIS FROM MIDDLE IN CR COIL

0 1000 2000 3000 4000 5000 6000 7000 80000

500

1000

1500

2000

2500

3000

3500

POSITION OF THE DEFECT IN THE MIDDLECR COIL LENGTH

POSI

TIO

N O

F TH

E D

EFEC

T

DEFECT COUNT= 21

DEFECT(SCAB) POSITION ANALYSIS AT HEAD END AND TAIL END IN HR COILS

200 400 600 800 1000 1200 14000

50

100

150

200

250

300

350

400

DEFECT DISTANCE FROM HEAD END DEFECT DISTANCE FROM TAIL END

HR COIL LENGTH (m)

HR

DE

FEC

T P

OS

ITIO

N L

EN

GTH

(HE

AD

&TA

IL E

ND

)(m

)

COUNT AT HEAD END=94COUNT AT TAIL END=39

(FOR FOUR MONTHS DECEMBER, JANUARY, FEBRUARY AND MARCH)

DEFECT(SCAB) POSITION ANALYSIS FROM MIDDLE IN HR COILS

400 500 600 700 800 900 1000 1100 1200 13000

100

200

300

400

500

600

700

800

DEFECT AT MIDDLE

HR COIL LENGTH(m)

DE

FEC

T LO

CA

TIO

N(M

IDD

LE)(

m)

DEFECT COUNT AT MIDDLE =11

(FOR FOUR MONTHS DECEMBER, JANUARY, FEBRUARY AND MARCH)

6 7 8 9 10 11 120.00

2.00

4.00

6.00

8.00

10.00

12.00

SLAB HEAD END DEFECT(m) SLAB MIDDLE DEFECT(m) SLAB TAIL END DEFECT(m)

SLAB LENGTH(m)

SLAB

DEF

ECT

LENG

TH(m

)

COUNT AT HEAD END=92COUNT AT MIDDLE=14COUNT AT TAIL END=37

BACK CALCULATED FROM HR DEFECT LENGTH TO SLAB LENGTH DEFECT LOCATION

OBSERVATIONS AT HSM-2 AND CRM-2

CRM 2

• CONSIDERING 188 COILS FOR FOUR MONTHS.• BACKMAPPING THE DEFECT POSITION AT HR STAGE.

HSM 2• PARSYTEC IMAGES SEEN AND DEFECT POSITION WAS INDENTIFIED.

FOR FOUR MONTHS DECEMBER- MARCH COUNT PERCENTAGENO . OF COILS INSPECTED 188MATCHED COILS WITH DEFECT 77 40.96NO IMAGE AVAILABLE DUE TO SOME UNKNOWN REASON 65 34.57

NO CORELATION 46 24.47

FIG. SCAB OBSERVED IN HSM FIG. HOLES OBSERVED IN CRM

AT SMS 2 181 SLABS WERE

SELECTED OF GRADES JVHC130N00JVHC131NAO

JVHC120N00/NAOJVHC210NOO

& 15 FULL AUTO SCARFED

SLABS

TRACKING THE COILS AT HSM 2 AND LOCATING

THE DEFECT POSITION.

TRACKING THE COILS AT CRM-2

TRIAL SLABS

SLAB REMARKS OBSERVATION FOR 181(GRADE SPECIFIC)TRIAL COILS

OK /NOT OK SLAB ANALYSIS

OK /NOT OK SLABS COUNT %OK 128 70.7

NOT OK 53 29.2

Grand Total 181

OUT OF 181 COILS, 91 COILS HAVING DEFECT(SCAB) AT HSMDEFECT COILS OK/NOT OK ANALYSIS

OK/NOT OK COUNT %

OK 63 69.2NOT OK 28 30.8TOTAL 91

OUT OF 91 COILS SCARFED NOT SCARFED DETAILS

SCARFED/NOT SCARFED COUNT %

SCARFED 11 12.0

NOT SCARFED 80 87.9

TOTAL 91

SCARFED/NOT SCARFED SLAB DETAILSSCARFED/NOT

SCARFED COUNT %

SCARFED 24 13.3

NOT SCARFED 157 86.7

Grand Total 181

OK- NO ABNORMILITY SLABS NOT OK- ABNORMILITY SLABS

OBSERVATIONS

181 SLABS(GRADE SPECIFIC)

91 COILS WERE OBSERVED WITH DEFECTS AT HSM-2.

OUT OF 181, 153 COILS WERE PROCESSED AT CRM-

2 TILL MARCH OUT OF WHICH ONLY 4 COILS

WERE OBSERVED WITH DEFECTS.

15 SLABS(AUTOSCARFED)

10 COILS WERE OBSERVED WITH DEFECTS AT HSM-2

NO COILS WITH HOLES WERE OBSERVED AT CRM

HR THICKNESS ANALYSIS

• ABOVE CHART SHOWS MAXIMUM DEFECT LIES AT LOWER THICKNESS RANGE

2-3 3-4 4-5 5-6 6-70

5

10

15

20

25

30

0

5

10

15

20

25

30

2423

2

65

15

10

01 1

9

13

2

54

25.00

16.67

0.001.67 1.67

AS PER RUNDOWN THICKNESS WISE DEFECT ANALYSIS

NUM OF COILS ROLLED scab defect coils no scab defect coils %of scab defect

HR THICKNESS(mm)

NUM

OF

COIL

S

MOSTLY SCAB DEFECT WAS FOUND AT LOWER THICKNESS ONLY %of defect

RUNDOWN NUM(212921001-212921060)

SEM ANALYSIS

(a) Surface analysis • SEM image of sample revealed scab. • EDS analysis of scab region does not reveal any evidence of non-metallic inclusions.(b) Cross-sectional analysis • SEM image of sample revealed reduced thickness. • EDS analysis of scab region revealed a layer of rich oxygen content, must be oxidation. • No non-metallic inclusions are present.

SEM REPORT OF SAMPLE COLLECTED FROM HSM-2 SEM REPORT OF SAMPLE COLLECTED FROM CRM-2

Sample-1• EDS analysis shows no inclusion.• Microstructure shows equiaxed ferrite grains.

Sample-2• Shows complex CaO-MgO-Al2O3-SiO2 type Non-

Metallic Inclusions.

SAMPLE-1 SAMPLE-2

RESULTS AND DISCUSSION DEFECTS COMING FROM BOTH NORMAL AND ABNORMAL SLABS.

IT WAS ALSO FOUND THAT THE SCARFING HAS NO CORELATION WRT DEFECT

MAXIMUM DEFECTS FOUND AT HEAD END IN CR COILS , IMPROPER DEBURRING WAS SUSPECTED. TAKING TRAILS ON 4 SLABS ( 4 DEBURRED + 4 WITH THE BURR), NONE RESULTED WITH HOLES.

ALSO 8 SLABS WERE REVERSED AND CHARGED AND IN 3 COILS DEFECT OBSERVED IN THE HEAD END

THE PARSYTEC IMAGES FROM HSM-2 REPORTED SCAB AT THE HEAD END ON TOP SIDE.

NO CORRELATION WRT GRADE SPECIFIC WAS FOUND IN TRIAL SLABS.

SO, THE ROOT CAUSE SEEMS TO BE RANDOM FALLING OF SOME FOREIGN PARTICLES DURING THE INITIAL ROLL BITE AT HSM DUE TO DEPOSITION OF FEO ON ISC HEADER AND UPON FURTHER COLD ROLLING THE NON METALLIC PARTICLE COMES OUT THUS RESULTING IN HOLES.

IN SOME CASES THE HEAD END SLIVERS WERE ALSO FOUND TO BE LEADING TO THIS TYPE OF DEFECT.

F5 F6 F7

ICS

Thank You !