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ALUSTAR TM A Strong Material For Marine and Armor Plate Applications

ALUSTAR TM A Strong Material For Marine and Armor Plate Applications. ALUSTAR TM A Strong Marine & Armor Plate Material.

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ALUSTAR TM A Strong Material For Marine and Armor Plate Applications

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  1. ALUSTAR TM A Strong Material For Marine and Armor Plate Applications

  2. ALUSTAR TMA Strong Marine & Armor Plate Material • AL-Mg Alloys in General: Among all aluminum alloys, the non-heat treatable Al-Mg alloys (5xxx series) are the most suitable material for marine applications. Magnesium, as the main alloying constituent, lends itself to reasonable strength for marine applications. More important, however, is the corrosion resistance of Al-Mg alloys which makes them the most suitable material for shipbuilding. • Effect of Mg on Strength: The relationship between Magnesium content of 5xxx alloys and its mechanical properties, i.e. yield strength, tensile strength, and elongation, is given in slide 7. The main reason for increasing strength is the formation of Al-Mg intermetallic particles which reinforce the alloy. • Effect of Mg on Corrosion Resistance: Theoretically, increasing the Mg content will add to strength. However, when Mg% is raised above approximately 4%, the corrosion resistance of the alloy will gradually decrease. The reason for this phenomenon is that at higher Mg%, the Al-Mg intermetallic particles will start precipitating at the grain boundaries. These particles are anodic relative to Aluminum and thus they cause electrochemical imbalance in the grains which leads to “Inter Granular Corrosion”. This causes pitting and weight loss. Furthermore, IGC may lead to “Stress Corrosion Cracking”.

  3. ALUSTAR TMA Strong Marine & Armor Plate Material • Alloys AA5083 and AA5456: Alloy 5083 has been a popular shipbuilding alloy for a couple of decades. With the average Mg content of 4.4%, it provides a yield strength of 31 KSI, ultimate tensile strength of 44 KSI and an elongation of 10%. The corrosion resistance of AA5083 has been quite satisfactory for marine applications. However, the need for a higher strength marine alloy gradually became apparent as more aluminum vessels were built; specially for fast ferries and catamarans where weight saving and higher speed became an important issue. An alternative high strength alloy was AA5456 which is mainly used for military applications and coast guard vessels. The Mg level in this alloy is up to 5.5% which produces a yield strength of about 35 KSI and UTS of about 48 KSI with somewhat lower elongation (less formability). However, the lower corrosion resistance became evident as no special treatment for corrosion resistance was done. Although this alloy is still recommended in military and government specifications, Its use has drastically affected the design and maintenance of the vessels. For example, coast guard rescue bots made of this alloy have a very tight service interval. Also, for vessels operating in sea water (salt water), the lower part of the hull is painted with multiple layers of epoxy paint.

  4. ALUSTAR TMA Strong Marine & Armor Plate Material • Alloy AA5383: Alloy AA5383 was developed in the nineties, in an effort to increase strength. The Mg content of this alloy is slightly higher than that of AA5083 and this has increased the yield strength to 32 KSI or 220 MPa (about 1 KSI more than AA5083) while the UTS and Elongation remain the same. The yield strength and UTS after welding is 20 KSI and 42 KSI respectively and this is about 2 KSI higher than AA5083. There has been no official reports of reduced corrosion resistance as due to minimal increase in Mg content and strength, the difference in corrosion resistance with that of AA5083 may appear in several years. We are aware of one case where this alloy was used in a Catamaran which was exposed to elevated temperature (200 F) for a couple of months (the vessel was under extreme sunlight) and significant amount of pitting was reported. This was attributed to sensitization due to added Magnesium. Currently, several vessels made of AA5383 are in service. However, the slight increase in strength has not been used for down gauging and subsequent weight saving.

  5. ALUSTAR TMA Strong Marine & Armor Plate Material • Alloy AA5059 ALUSTAR: In the development of Alustar, we had two major goals; 1) Increase strength, both before and after welding, by at least 20% so that the user can use a thinner gauge and thus build a lighter vessel or alternatively build a vessel with 20% higher overall strength, and 2) keep the corrosion resistance at the same level or better than that of AA5083. • Strength: By adding up to 6.0% Mg, and subtle amounts of Zr and Mn we can guarantee a minimum yield strength of 270 MPa (39 KSI) and UTS of 370 MPa (53 KSI), while elongation (which lends itself to formability) remains at 10%. • Corrosion resistance: By the application of a proprietary thermo-mechanical process and the addition of controlled amount of Zn we were able to keep all the major intermetallic particles inside the grain and prevent any excessive electro-chemical imbalance and thus avoid corrosion susceptibility. Extensive corrosion tests performed and documented under the supervision of classification societies such as DNV show that the corrosion resistance of Alustar is better or equal to that of AA 5083. • Weld Properties: We have also been able to improve welding and heat affected zone (HAZ) strength by controlling the re-crystallization rate during welding and to avoid the formation of large grains.

  6. Alloying Constituents AA5083Alustar [Weight%] [Weight%] Mg 4.0-4.9 5.0-6.0 Mn 0.4-1.0 0.6-1.2 Zn 0-0.25 0.4-1.5 Zr - 0.05-0.25 Cr 0.05-0.25 0-0.3 Cu 0-0.10 0-0.4 Fe 0-0.4 0-0.5 Si 0-0.4 0-0.5 ALUSTAR TM A Strong Marine & Armor Plate Material CHEMISTRY

  7. Alustar: Influence of Magnesium Content On YS, UTS, and Elongation (5xxx alloys) 58 KSI 43.5 KSI 14.5 KSI

  8. ALUSTAR TM A Strong Marine & Armor Plate Material In Principle, increasing the Mg content In Aluminum Magnesium alloys will increase Strength. However, beyond 4.5% Mg, the Corrosion resistance decreases, due to Precipitation of ANODIC Al-Mg Intermetallic Particles at the grain boundaries. The alloy then Becomes susceptible to inter-granular corrosion. Using controlled amounts of Zn will create Mg-Zn intermetallics which in combination of Special thermo-mechanical processes, will stay Inside the grains and compensates for the electro-chemical imbalance. Mn and Zr are also added in controlled amounts to add strength and delay the process of re-crystallization in the HAZ to produce a fine grain structure after welding CORROSION RESISTANT MICROSTRUCTUREAA 5083 / H321 TEMPER SUSCEPTIBLE TO IGC CORROSION

  9. PROPERTIES AA5083Alustar Density at 20°C [g/cm³] 2.66 2.64 Approximate Melting Range [°C] 574-638 568-636 Coefficient of Linear thermal 20-100°C 24.2 23.0 expansion 20-200°C 25.0 24.5 [µm/m.K] 20-300°C 26.0 25.9 Specific heat at 20°C [J/kg.K] 900 890 Electrical conductivity at 20°C [%IACS] 29 27.1 Electrical resistivity at 20°C [µWcm] 5.95 6.3 ALUSTAR TM A Strong Marine & Armor Plate Material PHYSICAL PROPERTIES Physical Properties of AA5083 and Alustar Alloys

  10. 400 40 Thickness Range 2-20mm 350 35 300 370 30 ELONGATION (%) STRENGTH (MPa) 250 25 305 305 200 20 270 150 15 100 10 220 215 5 50 0 0 10 10 10 YS YS YS UTS UTS UTS Elongation Elongation Elongation AA5083 AA5383 ALUSTAR ALUSTAR TM A Strong Marine & Armor Plate Material MINIMUM TENSILE PROPERTIES TEMPER: H321 / H116 53 KSI 39 KSI 44 KSI 44 KSI 31 KSI 32 KSI

  11. 32 mm 32 mm 32 mm > 20 mm: > 20 mm: Min 10 % Min 360 MPa Min 260 MPa 25 mm 25 mm 25 mm 16 mm 16 mm 16 mm < 20 mm: < 20 mm: Min 370 MPa Min 270 MPa 14 mm 14 mm 14 mm 12 mm 12 mm 12 mm 10 mm 10 mm 10 mm Gauge Gauge Gauge 9 mm 9 mm 9 mm 8 mm 8 mm 8 mm 7 mm 7 mm 7 mm 6 mm 6 mm 6 mm 5 mm 5 mm 5 mm 4 mm 4 mm 4 mm 5 10 15 20 25 250 270 290 310 330 350 375 400 425 Proof Strength [MPa] Elongation [%] Ultimate Tensile Strength [MPa] ALUSTAR TM A Strong Marine & Armor Plate Material STATISTICS Tensile Properties of Several Lots of H321 Temper Alustar Alloy Material

  12. 300 290 275 160 140 125 ALUSTAR TM A Strong Marine & Armor Plate Material After WELD STRENGTH 42 KSI 43.5 KSI 40 KSI 300 250 23 KSI 200 STRENGTH (MPa) 23 KSI 20 KSI 18 KSI 150 100 50 0 UTS UTS UTS YS YS YS AA5083 AA5383 ALUSTAR MIG-welded Plates in H321 with AA5183 Filler Wire

  13. Typical Tensile Properties Obtained from Cross Weld Tensile Tests 40 40 35 35 16 16 Gauge[mm] Gauge[mm] 10 10 8 8 6 6 125 175 225 270 320 UTS [MPa] Yield Strength [MPa] ALUSTAR TM Material After WELD STRENGTH

  14. WELD POOL METAL BASE PLATE [ALUSTAR] BASE PLATE [ALUSTAR] HAZ HAZ FUSION LINE Grain Structure Modification by Welding By the addition of controlled amounts of Zr and Mn re-crystallization during welding Is delayed and a finer grain structure is achieved ALUSTAR TM A Strong Marine & Armor Plate Material WELD STRUCTURE

  15. 135 ALUSTAR (H321, t = 8 mm) 125 115 105 Hardness ( HV 5 ) 95 AA 5083 (H321, t = 8 mm) 85 75 65 0 10 20 30 40 50 60 Distance to the middle of weldseam (mm) ALUSTAR TM A Strong Marine & Armor Plate Material Hardnessprofile of MIG - welded Alustar H321 and AA5083 H321 ½” 1.0” 1.5” 2.0”

  16. ALUSTAR TM A Strong Marine & Armor Plate Material MIG - WELDING AND SIDE BEND TEST Alustar MIG-welded with Filler Wire AA 5183

  17. 400 375 350 UTS [MPa] 325 ALUSTAR 300 5083 Poly. (ALUSTAR) 275 Poly. (5083) 30 250 0 5 10 15 ALUSTAR 25 Additional Cold Reduction [%] 5083 Poly. (ALUSTAR) 20 350 Poly. (5083) Elongation [%] 300 15 250 Proof Strength [MPa] 10 ALUSTAR 200 5083 Poly. (ALUSTAR) 150 5 Poly. (5083) 0 5 10 15 100 0 5 10 15 Additional Cold Reduction [%] Additional Cold Reduction [%] ALUSTAR TM A Strong Marine & Armor Plate Material FORMABILITY Influence of Strain Hardening on Alustar and 5083 by Cold Deformation on Formability

  18. ALUSTAR TM A Strong Marine & Armor Plate Material BENDABILITY Photomacrograph Showing the 8mm Gauge Alustar Alloy Samples after Bend Test

  19. ALUSTAR TM A Strong Marine & Armor Plate Material CORROSION TEST METHODS ASSET Test [ASTM G66] Measures Pitting and Exfoliation Resistance Materials Tested : Unwelded / Welded / Various Gauges Sensitized and Un-sensitized Weight Loss Test [ASTM G67] Assesses Intergranular Corrosion Materials Tested : Unwelded Plate / Various Gauges SCC [ASTM G39/AIR 0948-147] Materials Tested : Unwelded / Welded / Various Gauges Sensitized and Un-sensitized

  20. Plate Welded Panel AA5083 Alustar AA5083 Alustar MIG-welded with AA5183 ALUSTAR TM A Strong Marine & Armor Plate Material CORROSION TEST ASSET Corrosion Test Results before and after Welding of AA5083 and Alustar

  21. ALUSTAR TM A Strong Marine & Armor Plate Material CORROSION TEST Surface of Sensitized Samples after the ASSET Test

  22. ALUSTAR TM A Strong Marine & Armor Plate Material STRESS CORROSION Method: Intermittently Immersion in 3,5% NaCl (AIR 9048 Test). Applied Stress (LT): 195 N/mm2 (130 N/mm2 Welded) Gauge Thickness: 8, 10, 12, 16, 20, 25 mm. Material: Alustar sensitized for 7 days at 100º C Result: No SCC after 8000 hours

  23. ALUSTAR TM A Strong Marine & Armor Plate Material FATIGUE AFTER WELDING S-N Curves (24)170 ALUSTAR/AA5183 STRESS (KSI)MPa (19)130 AA5083/AA5183 (13)90 (7)50 1,00E+05 2,10E+06 4,10E+06 6,10E+06 8,10E+06 1,01E+07 NUMBER OF CYCLES

  24. ALUSTAR TMA Strong Marine & Armor Plate Material ALUSTAR TM A Strong Marine & Armor Plate Material SUMMARY • Mechanical Properties, Fatigue and Impact More than 20% better than AA5083 before and after Welding • Corrosion Resistance Better or equal as AA5083 before and after Welding and in Sensitized Condition • Formability, Weldability, Toughness and Physical PropertiesComparable to AA5083 • Consistent Quality and Manufacturing Experience Several Thousand Tons in Fast Ferry, Military and Yacht Applications • Approvals from Major Classification Societies Improvement of Design Criteries by Fatigue Testing on Construction Details

  25. ALUSTAR TMA Strong Marine & Armor Plate Material • For Further Information:- • Tel:- +44 20 7681 1505 • Fax- +44 870 168 0554 • Email:- info@aluminumnow.com • Websites:- www.aluminumnow.comwww.catamaranferries.com

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