This document discusses quality assurance processes and defect analysis for stainless steel production. It covers feasibility studies, material testing including chemical analysis and mechanical testing, certifications, common defects at different production stages, and a case study on reducing sliver defects through chemistry and process modifications. The key quality assurance areas discussed are inspection, testing, process control, analysis of defects and improvements.

1. Quality Assurance
1. Inspection
2. Testing
3. Feasibility Study
4. Certifications
5. Customer Complaints
6. Process Control
7. Process Improvements
8. Defect Analysis
9. New Developments
10.Vendor Developments
Verticals of Quality Assurance

2. Feasibility Study
Marketing
• Raise the feasibility from customer end
• Feasibility contains customer requirement
PPC
• It act as bridge between QA /R&D & Marketing
• Comments on Delivery Time & MOQ
QA/R&D
• Studies the feasibility ( customer requirements)
in junction with operation team
• Provide comments on the customer requirements
Note: On order booking these requirements are mapped in to a Quality Plan/ Processing plan

3. Material Testing
Chemical Analysis
1. Incoming Raw Material Testing : Scrap, Ferro alloys & Pure Metals
2. Heat Chemistry Analysis : EAF/ Induction, AOD,LRF,VD & Caster
3. Slag Analysis : EAF/ Induction, AOD,LRF
4. Fuel Analysis : LSHS , LDO, LVFO, FO, Diesel , Bio Fuel
5. MRO items
Equipment Utilized
Spectrometer
XRF
Gas Analyser
Calorimeter
Wet Analysis

4. Mechanical Testing
1. Hardness
2. Tensile Testing ( UTS,YS & Elongation, R bar)
3. Impact testing
4. Bend Test
5. Metallographic ( Microstructure & Inclusion)
6. Corrosion Testing
7. Cupping & Draw ability
8. Roughness & Reflectivity

5. Other Testing
 Dimensional
 Flatness
 Camber
 Burr
 Dimensions
 NDT
 Visual Testing
 Ultrasonic testing
 Liquid Penetrant Testing
 Magnetic Particle Inspection
 SEM Study
 Slow Strain rate Testing

6. Certifications
 BIS ( Bureau of Indian Standards) : Indian Standards
 ASTM /ASME : American Standards
 DIN : European Standard
 JIS : Japanese Standard
 Norsok : Standard for Certifying Duplex grades for Oil & GAS
 NABL ( National Accreditation Board for Laboratories) : Certification of labs
 ISO Standards Sr.No ISO Certification Field
1 ISO 9001 Quality Management
2
ISO 14001 Environmental Management
3
ISO 45001 Occupational Health and
Safety
4
ISO/IEC 17025 Testing and Calibration
Laboratories
5 ISO 50001 Energy Management

7. DEFECTS IN STAINLESS STEEL
SMS
DEFECTS
COLD ROLLING
DEFECTS
TEXT TEXT
•Sliver –C
•Sliver – S
•TiN Segregation
•Central Porosity
• Chocking
• Pin Hole
• Sliver – B
• Digs & Gouges
• Scale Pit
•Pitting
•Rolled In scale
•Dishing
• White patches
•Brush Chatter
• Buckling
• Dents
• Edge Crack
• Pinching
• ILP Mark
•IMR Mark
•Roll chatter mark
•Roll Mark
• Poor Coiling
• Inter wrap
scratches
• Rolled scratches
• Telescopicity
HOT ROLLING
DEFECTS
MECHANICAL
DEFECTS

8. Case Study on Defects
Chillier type defect appearing
on the edges of coils
Description of Action taken for reduction of sliver dilemma :
Modifications and addition of boron in chemistry to control ferrite content during heat making
 Modification of WBF holding & its temperature
Benefits surfaced from the Project :
Significant reduction in Defect level from 10.80 % in FY 16-17 to 2.1% (from Jun-17 to
Feb-18) i.e. 81% improvement in reduction of defect level.
On time customer deliveries which were being hampered earlier due to high diversions
Elimination of eternal problem from process.
Saving as downgrading of 304L grade coils into 304 grade has been diminished
significantly.
Horizontal deployment of actions to other High Ni Variants

9. Actions taken
 Modification of chemistry
 Addition of boron
Control of calculated ferrite up to 4.0 Max
 Modification of WBF holding w.r.t Ferrite content
Option Mo Range C (ppm) Si Mn P S N2(ppm) Cr Ni Cu B (ppm)
Option 1 If Mo<=0.1%
220 1.7 - - 700 18.03 8.03 - 20
270 0.3 1.9 0.04 0.003 800 18.2 8.08 0.7 30
Option 2 If Mo 0.11-0.15%
220 1.7 - - 775 18.03 8.03 - 20
270 0.3 1.9 0.04 0.003 875 18.2 8.08 0.7 30
Option 3 If Mo 0.16-0.25%
220 1.7 - - 850 18.03 8.10 - 20
270 0.3 1.9 0.04 0.003 1000 18.2 8.15 0.7 30
Option 4 If Mo 0.26-0.35%
220 1.7 - - 850 18.03 8.15 - 20
270 0.3 1.9 0.04 0.003 1000 18.2 8.2 0.7 30
Grade Measured Ferrite PHF WBF Holding Time
304L/1.4307
≤ 5.0 No 2:45-3:15 Hrs
5.1-7.49 No 3:00-3:30 Hrs
≥ 7.5 No Min. 3:30 Hrs

10. Sliver B+C(E) trend
10.80
8.10
2.10
0.74
0.00
2.00
4.00
6.00
8.00
10.00
12.00
Fy 2016-17 Aor'17-May'17 June'17-Mar'18 FY 2018-2019
%Edge Sliver in 304L/1.4307
%Edge Sliver
93% reduction in
Defect Level