Cr+16 austenitic 18924.pptx Higher Yield strength material help in reducing overall weight of a component

Stainless Steels normally have lower yield strength. This development details manufacture of high yield strength Stainless steel

1. Welcome Salem collective for the technical discussion on Cr +16 austenitic

2. Why this development?

3. Cr +16 austenitic

4. Cr +16 austenitic

5. Cr +16 Austenitic

6. Cr +16 Austenitic Michel Basson Executive Director Southern Africa Stainless Steel Development Association I have contacted him for inputs on Cromanite . He provided the details. Middleburg discontinued Cromanite when there was amalgamation of Plants

7. Cr +16 Austenitic Stainless steel producers all over the world developed the equivalent of 3CR12 for material handling applications On developing, India christened it 409M (RDSO/Railways nomenclature-IRSM 44 and X2CrNi12-CK 201) Cromanite found applications where high strength, fabricability, corrosion resistance, wear resistance are the prime requirement Middleburg was keen to develop nickel free industrial grade stainless steel which resulted in 3CR12 and Cromanite

8. Cr +16 Austenitic Cr +16 CrCr +16 Austenitic +16 Austenitic CR+16 Austenitic grade will thus be an innovative adaptation - to combine the best of attributes required for drawability, corrosion resistance etc at a much lesser cost.

9. Cr +16 Austenitic Cromanite is the base for CR+16 Austenitic grade chemical composition. Austenitic grade SS is the workhorse in the SS industry world over. It has general corrosion resistance and workability Processed to different strength levels (by subcritical annealing and cold reduction). Present day low Nickel SS is metastable with high Carbon With limitations in fabrication and forming operations.

10. Cr +16 Austenitic

11. Cr +16 Austenitic Element-% CR+16 Austenitic Cromanite Carbon 0.05 0.03 Chromium 18 18/19 Manganese 10 10 Nickel 1.5 0.9 Silicon 0.8 0.8 Nitrogen 0.25 0.45 Copper 2 - Boron 10-20 ppm - Cromium equivalent is %Cr+1.5 SI Nickel equivalent is %Ni+30(C+N2)+0.5 Mn+0.5Cu

12. Common low Nickel and 304 SS composition Cu max N2 max 4 0.25 1.5 0.2 0.1

13. Cr and Ni equivalents Grade Cr equivalent Ni equivalent 204 Cu 17.4 15 U-SD 15.75 14.08 304 18.9 13.55 Cromanite 19.7 20.3 Cr+16 austenitic 19.2 15

14. Schaeffler diagram and grade position 1 2 3 4 5 2.4 Cu-M+A U-SD-M+A 304-A+2FN Cromanite -A A+2FN

15. Y.S Factor in SS Elasticity and plasticity

16. Y.S factor in SS Stress-strain curve

17. Y.S factor in SS Cold work hardening Strength Springback Stress Corrosion Failure Residual Stress Ductility

18. Elements contribution to strength

19. Y.S evaluation from Chemical composition -By Irvine YS=15.4(4.1+32N+23C+1.35Si+0.24Cr+0.16D+0.46d -0.5 Where D is Delta Ferrite and d is grain size in micron With this calculation for Cr +16 austenitic Y.S can be between 300 and 350 Mpa max

20. Steps ahead ….... Trial production of a heat of Cr+16 austenitic grade Final CRSS coil width 1000 mm – to plan slab size accordingly Deep draw trials comparing 204 Cu (Salem & JSL), 304 (Salem & JSL) and Cr+16 austenitic grade 10 circles in each grade variant – 5 for deep draw :: 5 for shallow draw Take up the data of test results for BIS certification

21. Concluding.. Estimated slab cost for Cr+16 austenitic-around Rs.100/kg Cr+16 austenitic will have good drawability and weldability Lower Y.S High elongation Lower work hardening As good as 304 Only a trial production will help in standardizing the parameters

22. Reflecting on the 2001 studies

23. Extracts of Comparative Studies on SSLN1, SSLN4 and 304 vis a vis material of competitor carried out in 2001, will be a useful template to follow. While we had to do trials then through out sourced facilities like RK Alloy, Murugan Metals etc. the same can now be done at SBU.

24. Schaeffler Diagram Plotting for SSLN 1 grade, made in 2001

25. Chemical and Mechanical properties – Test results of the testing done in 2001

26. Thank you for your time