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A Case Study on throughput improvement in a Steel Melting
Shop
Presentation Contents
Tata Steel Overview01.
Tata Steel Value Chain02.Case Study : Simulation 03.a) Business Challengeb) Approach & Objectivec) Simulation & Analysisd) Insights & Outcome e) Ways ahead
Presentation Contents
Tata Steel Overview01.
Tata Steel Value Chain02.Case Study : Simulation 03.a) Business Challengeb) Approach & Objectivec) Simulation & Analysisd) Insights & Outcome e) Ways ahead
Tata Steel Overview (1/3)
Employee base comprises of over 74000 people in ~ 50 counties
Industrial harmony of over 88 years
First integrated steel plant to receive DGP & DEMING Prize (outside Japan)
India’s 1st steel company to receive “Green Co‐Platinum Rating” by CII‐GreenBusiness Centre
A Fortune 500 company & world’s second most geographically diversified steel producer
Sustainable and highly cost efficient operations in India
Flat Produ
cts
Long
Produ
cts
Selling by pieces
• Fastners• Tyre bead wire• Construction electrodes
• Springs• Doors
• Large construction projects
• Individual houses
ProductsKey Customers Application Unique offering Focused segment
Hot Rolled (HR) Strips
Cold Rolled (CR) Sheets
Galvanized CR Sheets
Reinforcement bars for construction
Wire Rods
•Auto, •Commercial,•General Engineering
•Auto,• Steel Roofing•General Engineering
•Auto, •General EngineeringDistribution
•General Engg Direct
Customer Products & BrandsTata Steel Overview (2/3) :
50% LPG cylinders in India are made from Tata Steel HR coil
Nearly all the 1p, 2p, 5p and 10pcoins in the UK are made fromsteel made at Port Talbotplant
75% of Singapore’s scrap isconsumed and recycled byNatSteel
Almost every model inautomotive has some steel fromTata Steel
50% of UK car makers fulfil their steelrequirements from Tata Steel UK
Nearly every Gillette bladeworldwide contains Tata SteelChrome
Every 4th stainless steelutensil in India is made fromTata Steel chrome ore
4 Million Households servedby Tata Steel retail brands (TataTiscon, Shaktee, Durashine)
Interesting Steel FactsTata Steel Overview (3/3):
Presentation Contents
Tata Steel Overview01.
Tata Steel Value Chain02.Case Study : Simulation 03.a) Business Challengeb) Approach & Objectivec) Simulation & Analysisd) Insights & Outcome e) Ways ahead
RAWMATERIALS
IRONMAKING
STEELMANUFACTURING
DOWNSTREAMPROCESSING
MARKETING& SALES
CUSTOMERS
Tata Steel Value Chain
Torpedo Station Desulphurization LD Converter Slab Caster Slabs
Removing sulphur by
injecting CaC2 and Mg
Removing C,Mn,P & Si
Vertical & Bow casting
Hotmetal premixing & and ladle filling
Steel Making Process Overview
Presentation Contents
Tata Steel Overview01.
Tata Steel Value Chain02.Case Study : Simulation 03.a) Business Challengeb) Approach & Objectivec) Simulation & Analysisd) Insights & Outcome e) Way ahead
Background: Steel Melting Shop team observed potential to improve vessel charging rate by improvising
upon existing business rules for handling Cranes and other logistics systems. Existing business rules for handling cranes induce crane idleness mainly while transferring
hot metal to charging vessels and while unloading empty buckets on transfer car in pit(s) thereby resulting into loss of charging/heats.
There was a need felt to carry out a study to check and validate whether modifying business rules for handling cranes and other systems help in improving throughput.
10
3.(a) Business Challenge
Torpedo Station
Desulphurization LD Converter Slab Caster Slabs
Removing sulphur by
injecting CaC2 and Mg
Removing C,Mn,P & Si
Vertical & Bow casting
Hotmetal premixing & and
ladle filling
Problem Solving Approach : (Simulation)
Identification of problem
Problem Worth Simulating?? Defining Objective Data Collection
& ModellingValidation,
Modification, Report
3.(b) Approach & Objective
Objective :
Simulation study to optimize internal logistics of Steel Making unit with the objective to increase throughput.
3.(c) Simulation Modelling & Scenario Analysis :n Study
3 Scenario were modelled in the Simulation with modified logic of Crane operatingphilosophy :
(1) Using both charging bay crane for Vessel Charging (Existing)(2) Using Crane2 mainly for Vessel Charging, Using Crane 1 while doing parallel charging.(3) Scenario 2 + provision for parking empty bucket at 9m floor.
While creating scenarios ,the objective was to reduce waiting time for Vessels and creatinglogic which offer least interference to charging crane with other crane.
90 Experiments were designed for each scenario by varying DS and Vessel processing time toobserve Heats produced per day ,Crane utilization , waiting time of Vessels .
Simulation Snapshot
Simulation Model Snapshot
L 3.(d) Insights & outcome (1/3) :
Scenario 2‐Scenario 1
Scenario 3‐Scenario 1
Scenario3‐Scenario2
Mean 1 4 3
Median 1 4 3
Statistical Centrality Measures: • We observe that Heats gain per day is more and Vessel Waiting Time is lesser in Scenario 3 with respect to Scenario 2 and Scenario 1.
‐2
0
2
4
6
8
1 4 7 101316192225283134374043464952555861646770737679828588
Comparison: Heat Gain Per Day
Case2‐Case1 Case 3‐Case 1 Case3‐Case2
‐3.00
‐2.00
‐1.00
0.00
1.00
2.00
3.00
1 5 9 13 17 21 25 29 33 37 41 45 49 53 57 61 65 69 73 77 81 85 89
Vessel waiting time comparison
Case2‐Case1 Case3‐Case1 Case3‐Case2
0102030405060708090
Exp 01
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Exp 81
Exp 85
Exp 89
ChargingBayCr 1Utilization(%)
Case 1 Case 2 Case 3
L 3.(d) Insights & outcome (2/3) :
• We observe that Charging Bay Crane 2 Utilization is around 80% in Scenario 3 which is slightly undesirable. For this we recommended to have a robust preventive maintenance plan along with use of crane 1 more frequently in case of liquid charging.
0
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40
60
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Exp 01
Exp 05
Exp 09
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ChargingBayCr 2 Utilization
Scenario1 Scenario2 Case 3
L 3.(d) Insights & outcome(3/3) :
Result: The statistical analysis of simulation outcome suggests that Scenario 3 has a significant
advantage ofminimum 2 heats/day over Scenario 2 and Scenario 1. It was observed that in Scenario 3 ,Crane utilization and waiting time of Vessels also
improves significantly. Scenario 2 is slightly better than Scenario 1. Scenario analysis suggest it’s always better to use 2nd charging bay crane only for
charging vessels rather than using both the cranes for charging. Provision for parking empty bucket at 9m floor will improve throughput significantly.
L 3.(e) Ways Ahead :
1. Requirement from Business : Incorporating Scrap charging compulsory into the model and analyzing the effect.
2. Finding the best parameters for arriving at the global optima of the system.
3. Using Optimization to find the best combinations of the different input parameters at various levels of production flow .
Thanks
Q & A
Backup
Why Simulation is required?
The system operates in very complex environment. Most of the crane handling related decision making are manual and taken
by different persons for different cranes . Handling various cranes in coherence to optimize the overall process is
tedious task. Moreover, there are many variability/randomness in the system (e.g. process
time of Vessels/DS, downtime etc.) The customer wanted some simple thumb rule to operate cranes so as to
involve least human dependent decision making in various cases and thereby optimizing overall process.
In this purview, there was a need to carry out a simulation study.
System understanding (1/3)
Crane1 Crane2 Crane3
Charging Bay
Torpedo Bay
Torpedo Bay Crane
Steel Melting Shop Schematic
V1 V2 V3
DS1 DS2 DS3
System understanding (2/3)
Crane1 Crane2 Crane3
Steel Melting Shop Schematic
System understanding (3/3)
Steel Melting Shop Schematic
Crane1 Crane2 Crane3
Torpedo Bay Crane
Data Collection
Major Assumptions1.Vessels availability = 87.5% of simulation time2.The system scope is from hot metal unloading from torpedoes into buckets to Vessel taping. (Activities prior to hot metal unloading from torpedoes and post taping are out of scope of this study)3.In simulation, trigger goes to scrap crane 5 mins before charging gets completed in a vessel, to be ready with the scrap for charging.4.Simulation is run for a period of 10 days post warm up period.5.Transfer cars are always available (no downtime).