final ppt cal + etl
TRANSCRIPT
Continuous Annealing Line and Electrolytic Tinning
Line
JSW STEEL COATED PRODUCTS Ltd. Tarapur
Total Capacity : 0.75 MTPA. Source coils : Vijaynagar and Dolvi.
India’s largest producer and exporter of Coated Products
The plant has 5 cold rolling mills and five coated strips division (two dual pots galvanizing cum galvalume lines, two colour coated lines and a 30 MW captive power plant)
Specialized in Galvanizing , Galvalume and colour coated steels.
H.R. SLITTING
PICKLING
H.R. COILS
COLD ROLLING
GALVANIZE
GALVALUME
DISPATCH
COLOUR COATING
PROFILING
CORRUGATED SHEET
WHY CAL?
Uniformity of products
Large production volumes
Less labor requirement
LINE SPECIFICATION:Type : Continuous annealing line
Furnace Capacity: Grade Ref size(mm)
Speed (mpm)
Capacity(TPH)
T3 1000*0.2059
374.4 38.8
T2.5 1000*0.1991
398.3 37.5
T2 1000*0.1926
385.2 36.3
T1 1000*0.1801
400 33.9
T4/T5 1000*0.2317
370.7 43.7
DR08/DR10
1000*0.2253
391.8 42.4
Fuel : RLNGLCV : 8500Kcal/Nm^3
MATERIAL SPECIFICATION:Weight 5000 – 25000 kg
Inner diameter 508 mm
Outer diameter 900 – 2000 mm
Strip thickness 0.14 – 0.6 mm
Strip width 650 – 1250 mm
Tensile Strength 700 – 800 MPa
ANNEALING FURNACE Preheating section
Radiant tube section
Soaking Furnace(SF)
Rapid Cooling Section(RCS)
Overaging sections(OA)
Final cooling section(FC)
Water quenching section(WQ)
Typical annealing cycle in a CAL
STEEL GRADE
Heating exit
SF RCS OA FC WQ
Temp( C)
Temp( C)
Time(s) ExitTemp(C)
Enter Temp(C)
Exit Temp(C)
Time(s)
Temp(C)
Temp(C)
T3 710 710 20 400 400 380 60 <=140 45
T2.5 720 720 20 400 400 380 60 <=140 45
T2 730 730 20 400 400 380 60 <=140 45
T1 750 750 20 400 400 380 60 <=140 45
T4-T5 670 670 20 - - 360 - <=140 45
DR8-DR10 680 680 20 - - 360 - <=140 45
Thermal cycle
0.15 0.2 0.25 0.3 0.35 0.4 0.45 0.5 0.55 0.6 0.650
50
100
150
200
250
300
350
400
450
PRODUCTION CURVE
T3T2.5T2T1T4/T5DR08/DR10
strip thickness(mm)
Lin
e sp
eed(
mpm
)
Effect of annealing(at different temperatures) on Hardness
ELECTROLYTIC TINNING LINE
ELECTROLYTIC TINNING LINE
PROCESS DESCRIPTION:
• Entry Section : (Entry coil car, Welder, Accumulator, Bridle units, Deflector rolls, Pinch rolls, Steering system, CPC)
• Process Section : (Cleaning section, Pickling Section, Tin Plating section, Reflow of tin, Chemical Treatment Section, TFS section)
• Delivery Section (exit) : (Vertical Inspection System ,Exit accumulator, Exit thickness gauge, Exit snip shear, automatic edge position control, Tension reel, Exit coil cars)
Processes incurred in an ETL :
• Cleaning and Pickling : removing loose particles and rolling oils
Cleaning/Pickling Process : Electrolytic Cleaning/Pickling Current : 18000 A – 32 V
• Tin Plating :
12 vertical tanks, 9 for electroplating and 3 (for drag and rinse) Plating Process : Phenol Sulfonic acid Plate(PSA & Future provision for MSA) Plating Current : 153000 A – 32 V with 16 % plating efficiency
Electrolyte : Phenol Sulphonic Acid (PSA)
• Reflow :
Reflowing involves reheating the tin above its Melting Point(231C/450F) reduces the internal stresses improves the bond between the tin plating and the base material. provides good thickness uniformity and a glossy surface finish. Parts treated with reflowed tin exhibit excellent corrosion resistance. increase its solderability.
• Quench Tank : for lowering strip temperature to 45oC
Temp in/out (oC) 50/275
Power in strip (kW) 1000
• Chemical Treatment :
to stabilize the tin oxide layer (formed during induction reflow in the presence of air) by electrolytic treatment with sodium dichromate.
Temperature : 44-58 oC
• Oiling :
The clean, dried strip passes through an electrostatic oiler in which the required amount of lubricant is deposited.
• TIN FREE STEEL (TFS) Section : apply coatings of metallic chrome and chrome hydroxide on
the steel strip surface.
• Tin Free Steel :
Tin free steel (TFS) is composed of four layers, including steel base, metallic chromium layer, chromium oxide layer and oil film
INCOMING Coil Characteristics :
Material Medium and low carbon steel , cold rolled and tempered (EN 10202:2001)
Steel Grades • SR: T1 – T5 DR: DR480, DR8, DR9, DR10
Yield Strength • SR: 230 – 550 N/mm2
DR: 350 – 700 N/mm2
Coil weight 25 ton (max)I.D 508mmO.D 914-1950 mmSurface iron and oil 75-150 mg/m2 per side
OUTGOING Material Characteristics :
Material Tin Plate and TFSCoil weight 25 ton(max.)I.D 420/508mmO.D 914 - 1950 mmCoating Type Tin Plate(PSA & Future provision for
MSA) and TFS(2 steps)Coating weight Tinplate
0.56 to 16.8 g/m2 per sideTFS 50 to 140 mg/m2 per side(Chromium) 7 to 35mg/m2 per side (Chromium in Oxide)
Chemical Treatment • Sodium Dichromate 2 – 10 mg/m2 ,Cr each side (for 311 type) 1 – 3 mg/m2 ,Cr each side (for 300 type)
Entry section speed 500 m/min
Process section speed 400 m/min.
Exit section speed 500 m/min
Acceleration/Deceleration rate 45 m/min/s
Technical Data :
An alternative approach :
MSA as an electrolyte (instead of PSA) :
The MSA bath is a plating bath which is composed mainly of methane sulfonic acid (CH3SO3H) and Sn2, and has the following features:
• . Sludge generation is small
• Because the main components of the sludge are Sn(OH)4 and SnO2, recycling is easy.
• The proper electrolysis current density (10– 55A/dm2) is wide
Pitfalls of using an MSA bath :
• The MSA bath is strongly corrosive (pH 1).
• The unit cost of the electrolyte is extremely high in comparison with the halogen bath.
Thank You
Himanshu Sankhe