CRM Process & Products - Tata Steel - DigEca.pdf

Tata Steel - DigEca

1. CRCA Process and Products -
An overview
CR Technology Group, PTFP

2. 10
SHARED SERVICES
COLD ROLLING MILL
PROCESS FLOWSHEET
HRC FROM HOT STRIP MILL
COUPLED PICKLING & TANDEM COLD
MILL
H
2
BATCH ANNEALING
GALV. LINE FOR AUTO / APPLIANCES
GALV. LINE FOR ENGG / CONST.
MATL.
SKIN PASS MILL
RECOILING &
INSPECTION LINE
PACKAGING
LINE
SHIPMENT
ELECTROLYTIC CLEANING LINE Process Flow at CRM
JCAPCPL

3. Pickling Line and Tandem Cold Rolling Mill
Pickling section
TCM section

4. Electrolytic Cleaning Line

5. Batch Annealing

6. • Annealing Cycle time depends on the grade, and
the properties required

• Cycle time for some grades may be up to 50 hours
Batch Annealing

7. ‘WET’ Skin Passing
OILER
Work Rolls with
bending/tilting
arrangement
Encoders to measure
elongation
Skin-pass mill

8. •Improvement of mechanical properties of material –
1.Elimination of ‘Luder bands’ (on forming) in freshly annealed steels
2.elongation in the range of 0.3 to 2% increases the material yield strength
• Shape correction
The mill has bending and tilting facility , enabling preferential force application on certain
part of the width – this ensures a flat sheet to the customer
• Adjustment of surface properties – roughness
The SPM work rolls impart their features to the strip passing between them – The strip
roughness is thus a function of the WR roughness as well as other parameters (force etc.)
• Application of Rust Preventive oil
The SPM at CRM has oiling arrangement either by an oiler roll or an electrostatic oiler . For
coils not going to RCL , this the final oiling facility at CRM*
*Oil application may also be done at SPCs
Skin-passing

9. Re-coiling and inspection lines

10. Packaging

11. • ECL, annealing, skin-passing as a continuous process
• Very high productivity
• Very low lead time
• Less material handling and damage (better yield)
• Very low property variation within coil
•Better shape
• Capability to produce high strength steels (UTS > 440 MPa)
Continuous Annealing Line

12. • Multiple process changes required in upstream processes as well
• Various grades can be produced using similar chemistries (DQ/DDQ/EIF)
• JCAPCPL example -
Continuous Annealing Line
DQ grade
CRM BAF
JCAPCPL
(DQ chemistry)
JCAPCPL
(IF chemistry)
Parameter
AU03
SF58
TD04
JC25
TG04
JC26
C 0.04 - 0.06 0.02 - 0.045 0.0040 max
Mn 0.22 - 0.32 0.15 - 0.25 0.05 - 0.15
S 0.02 max 0.012 max 0.015 max
P 0.025 max 0.018 max 0.02 max
Si 0.04 max 0.04 max 0.04 max
Al 0.021 - 0.06 0.03 - 0.08 0.02 - 0.07
N (ppm) 60 max 40 max 40 max
Ti - - 0.045 - 0.065
CT (ͦC) 570 710 650

13. • CQ/D/DD -
Simple applications (bending, little draw)

• EDD
Considerable drawing involved

• IF (Interstitial Free)
Critical Draw and Stretch Components in terms of geometry of the component, type
and depth of draw and press parameters.

• IFHS
For components (Interstitial Free High Strength) involving draw and requiring
resistance against dent and impact

• HSQ
High Strength grade for crash resistant components etc.
• BH
Bake Hardening grade – hardening after painting
CRCA grades

14. Applications

15. Applications

16. Applications

17. Applications

18. Applications

19. Applications

20. Mill capacities and constraints
• Final SKUs (maximum rollable widths, minimum rollable thickness etc.) are restricted
based on the rollability at PLTCM
• These are specific to individual grades since they have different tensile strengths.
• Based on frequent feasibility trials and new customer requirements, any possible
expansion of rollable SKUs (GWT) are taken up.
• GWT example -
Current approximate capacities of
processing lines (in MTPA) -
• PLTCM - ~1.9
• ECL - ~0.5 (under upgrade plans to 0.7)
• BAF - ~0.85
• SPM - ~0.9
For illustration only

21. CRCA defects
• Defects can be broadly classified as surface and shape defects
• Shape defects - edge waviness (left), centre buckle (right)
• Examples of few surface
defects -
Sliver
RIS
Roll mark
Rubbing mark

22. THANK YOU !!!