1. 11 300 Series Stainless Steels A look at the grades, properties and applications

2. 2 300 Series Stainless Steel Welding Consumables “Austenitic Stainless Steels”  Iron Base (Fe) & Typically low Carbon (C)  Chromium (Cr) 15-30%  Nickel (Ni) 8-35%  Molybdenum (Mo) 0-5%  Mn, Si, Cu, Nb

3. 3 Stainless Steel Welding Alloys 308L 308H 308L(Si) 347 309L 309L(Si) 309LMo 316L 316L(Si) 317L 312 310 320LR 330 385 307 The Austenitic Grades: Non-magnetic May contain an important magnetic phase called ferrite

4. 4 Austenitic Stainless Steels A magnetic phase Can be estimated by Calculation diagrams or Measured Ferrite About 10FN It is not a chemical element!

5. 5 Austenitic Stainless Steels Ferrite Calculated using diagrams – based upon chemical element percentages. WRC 92 (Welding Research Council, 1992)  Cr eq = Cr + Mo +.7Nb Ferrite formers  Ni eq = Ni + 35C + 20N +.25Cu Austenite formers Delong Diagram (introduced Nitrogen – 308/316) Schaeffler Diagram

6. 6 Calculated by WRC 92

7. 7 Fischer Feritscope MAGNE-GAGE Ferrite Number Measured on Actual Metal Specimen

8. 8 B.2 Effects of Ferrite The most important effect of ferrite in nominally austenitic stainless steel weldments is the well-established relationship between a reduced sensitivity to hot cracking and the presence of ferrite. The minimum ferrite limit necessary to assure freedom from cracking depends, among other factors, on the weld metal composition. The upper limit results from possible impairment of either mechanical or corrosion properties, or both. The required amount of ferrite can be ascertained by adjusting the ration of ferrite formers (such as chromium) to austenite promoters (such as nickel) within limits allowed by the applicable specification. Ferrite in 300 Series Stainless Ferrite – the up side

9. 9 In High Temperature Applications, such as in refineries, >800F – Ferrite can transform to a brittle intermetallic phase – Sigma. The result is a lack of ductility. In Low Temperature Applications -320F – Ferrite can harm toughness Controlled ferrite content is the key! Intermetallic phases Ferrite – the down side Ferrite in 300 Series Stainless

10. 10 300 Series Stainless “Groups”  Basic Cr Ni  Cr Ni Mo  Dissimilar Metal Joining  Fully Austenitic

11. 11 Basic Cr Ni 18-8 Stainless302/304 base metal  308 Family 19.5-22.0% Cr, 9.0-11.0% Ni  308Lless Carbon.03% max  308Hmore Carbon.04-.08%  308LSI more Silicon.65-1.00%  347+ Nb 10xC min to 1.0% max

12. 12  308L304 joining GTAW, SAW, FCAW process  308HHigh Temp apps – hc Castings / Refineries  308LSIGMAW higher speed 304 joining  347High Temp, minimize CrC precip  308L”CF”Low Temp –Cryo, LNG Basic Cr Ni Applications

13. 13 Cr Ni Mo 16-18%Cr, 10-14%Ni, 2-3%Mo UNS S31630 Improved corrosion resistance – chlorides / pitting  308 Family 19.5-22.0% Cr, 9.0-11.0 Ni  316 Family 18.0-20.0% Cr, 11.0-14.0%Ni,2.0-3.0%Mo  316Lless Carbon.03% max  316LSImore Silicon.65-1.00%  317L +Ni (13.0-15.0), +Mo (3.0-4.0)

14. 14 Food processing, salt water  316L316 joining GTAW, SAW, FCAW process  316LSIGMAW higher speed 316 joining  316L”CF”Low Temp –Cryo, LNG coastal areas, ocean transport  317LUpgrade to 316L for additional corrosion protection Basic Cr Ni Mo Applications

15. 15 Dissimilar Metal Joining Carbon Steel to Stainless - Dilution  308 Family 19.5-22.0% Cr, 9.0-11.0 Ni  316 Family 18.0-20.0% Cr, 11.0-14.0Ni, 2.0-3.0Mo  309L Types 308 +Cr +Ni 23.0-25.0%Cr, 12.0-14.0% Ni  312308 ++ Cr 28.0-32.0%Cr, 8.0-10.5% Ni  18 8 Mn (307)5.0-8.0Mn, 17-20Cr, 7-10Ni  23 12 2 L(309LMo)309L plus 2.0-3.5% Mo

16. 16 Dissimilar Metal Joining

17. 17 Dissimilar Metal Joining Centerline Hot Crack  Minimize dilution of carbon steel to prevent centerline cracking (lack of ferrite)  In cases of high dilution, 312 may be the best choice  PWHT / Stress Relief can make high ferrite welds brittle – might be a factor

18. 18 Alert Not all AWS ER309LSi wires are the same. For Hot Mills / Rolling HRAP rod with high ferrite content is difficult. Higher scrap, higher cost….. Premium brands like Lincoln Bluemax 309LSi have higher min FN levels Bluemax may work where other 309LSi brands will not.

19. 19 Specialty Grades  31027%Cr21% Ni  33016%Cr35%Ni  320LR20%Cr34%Ni2.5%Mo 3.4%Cu  38521%Cr25%Ni4.6%Mo 1.6%Cu Applications  High heat  Severe corrosion  Heat treat furnace components, baskets  Chemical containment tanks Fully Austenitic

20. 20 Welding Fully Austenitic Stainless Steels 310, 320, 330, 385 No Ferrite Susceptible to hot cracking – Centerline cracking

21. 21 Reminder! Ferrite – the up side

22. 22 Fully Austenitic

23. 23 Welding Fully Austenitic Stainless Steels 310, 320, 330, 385 No Ferrite  320LR “Low Residual” reduces crack sensitivity (less C, Si, P, S)  No preheat  Maximum interpass temperature of 212°F (100°C)  Low heat input  No weaving  Small weld puddle  Make an “ugly weld” with more reinforcement, convex fillet not concave fillet  Electrodes with -15 or -16 coatings, not -17

24. 24 Summary 300 Series Stainless  Understanding starts with 18-8 and add on  Understand “ferrite” is important  Understand properties and applications change with sometimes small adjustments to composition