Advanced M aterials and Laser Advanced M aterials and Laser based - PowerPoint PPT Presentation

Advanced M aterials and Laser Advanced M aterials and Laser based based Welding Technologies Welding Technologies

Automotive sector Industry trends Need to reduce CO 2 emissions in exhaust gases to fight global warming  Improvement of combustion efficiency  Reduction of vehicle weight  Reduction of loss of efficiency through friction  M aterials development  M aterials development  Welding Processes  Welding Processes Trend towards light-weight design is widely established Trend towards light-weight design is widely established Steels with very high ultimate tensile strength increasingly applied Steels with very high ultimate tensile strength increasingly applied Advanced materials • High tensile strength steel materials- Advanced High Strength Steels (AHSS), Ultra High Strength Steels (UHSS) • Galvanised steel • Aluminium • M agnesium • Composites

5 out of 38 Advanced Transportation T ech Projects of US DoE (Sept 2013) • Oak Ridge National Laboratory - Body-in-white Joining of Aluminum to Advanced High Strength Steel at Prototype Scale: - solid-state spot joining technology • Johns Hopkins University - heat-generating foils to provide strong and stable bonds between aluminum alloys, magnesium alloys and steels. • Oak Ridge National Laboratory - laser-assisted joining of aluminum and carbon fiber components • The Ohio State University - Vapor-assisted collision welding of dissimilar metals. • M ichigan State University, Composite Vehicle Research Center - bonding, reparability and reassembly of dissimilar materials using thermoplastic adhesives

Some candidate components Aluminium outer skin – Steel inner Aluminium support of roof; closures such as doors, bonnet and hood Steel Reinforced plastic Plastic sections – to steel pillars and side members Reinforced plastic floor sections – Aluminium body frame 4

M ulti-M aterials Joining for Lightweighting (M ultiJoin) Project being implemented in India with support of Technology Development Board

“M UL TIJ OIN” Project: Demonstrator assembly (2 m X 1m) aluminum Robotic CM T weld brazed prototype

Laser Brazing  Useable for joining Steel/Aluminium, Steel/ Steel and Aluminium/Aluminium  Car body: M ass reduction up to 26% (AUDI) through mixed materials and smaller flanges  Adapted joining configurations Overlap Flange St Al Al Al St St  Short cycle times through high brazing speed (4 m/min)  Flexible seam geometries by using a robot for laseroptic and wire feed  Systems for Quality assurance available (SmartRay 3D for surface porosity, undercut, geometry)

Automotive sector Advanced High Strength Steels (AHSS) M icrohardness M apping: Local hardness variation and HAZ Softening Static Tensile Failure Location Correlates to HAZ Softening Region * Zhili Feng, Oak Ridge National Laboratory

Automotive sector Laser welding of Advanced High Strength Steels (AHSS) Fully penetrating butt welds Fully penetrating lap welds could could be achieved at 5- be achieved in 0.8-1.5mm 8m/ min, with 4kW of laser thickness at 2.5-6.5m/ min with power and a 0.6mm diameter 4kW of laser power and a 0.6mm laser spot, depending on diameter laser spot. welding thickness. welding speed speed could be increased by 40% could be increased to 10- and 200-700% respectively, 17m/ min for the same laser depending on thickness of steels, power when a 0.4mm when 0.4 and 0.2mm diameter diameter laser spot was used. laser spots were used. Tensile strength Formability Tensile strength of butt welds in a range of steels produced with 4kW of laser power and a * Steve Shi, Steve Westgate, TWI Ltd 0.6mm diameter spot

Laser processing of AHSS • Use of Advanced High Strength Steels – Hard cut edges – Soft weld heat affected zones • Solution a hybrid laser beam source, fiber laser for cutting & joining and diode laser for local heat treatment Source: IL T Aachen

Power- Nuclear Evolution of four generations of ferritic steels (Viswanathan and Bakker,2000) • M odified 9Cr-1M o Steel- High temperature components of fossil-fired power plants, steam generators of nuclear power plants • Oxide dispersion strengthened (ODS) ferritic steels - clad tube material for oxide fuels, better creep properties up to 700°C • Reduced Activation Ferritic-M artensitic Steels- candidate structural materials for TBM to be installed in the ITER Fusion Reactor

Power - Nuclear Trends of welding processes for nuclear power plant (Courtesy: Satoru Asai)

Power- Thermal Steam parameters development of coal fired power plants Ratio change of high temperature materials with steam parameters development

Problems in fusion joining of Ni based super alloys • Liquation cracking at grain boundary in PM Z • Sluggish nature of molten pool • M icrofissuring in reheat zones of multipass welds

Laser hybrid BOP welding of 10 mm thick IN 617 Super Alloy Bead on Plate welding trials Precipitate coarsening M IG-FZ Laser-FZ Proc Wire Laser M ount speed feed Shielding power Id (m/ min (m/ min gas (kW) ) ) INLHW- He:Ar=80: 3.5 1 8 SEM images of LHW-3 FZ, HAZ & Laser SEM images of LHW-3 FZ, HAZ & Laser 1 20 INLHW- He:Ar=80: M IG-FZ 3.5 1 10 Precipitate coarsening Laser-FZ 2 20 INLHW- 3.5 1 8 He=100% 3 INLHW- 3.5 1 10 He=100% 4 SEM images of LHW-4 FZ, HAZ & Laser SEM images of LHW-4 FZ, HAZ & Laser LHW-1 LHW-2 LHW-3 LHW-4 M IG Fusion zone M IG-HAZ • EDS images of LHW-3 indicate enrichment of FZ dendritic boundary & HAZ coarsened precipitate with M o Hardness survey across the weld Hardness survey across the weld Hardness survey along the weld Hardness survey along the weld

Defence Rocket motor casing Composition (wt%) C Ni Co M o Ti Al Fe 0.01 18 7.75 4.9 0.40 0.10 Bal M icrostructure Applications Rocket motor cases, cryogenic missiles, submarine hulls, landing gears, tooling and machinery Properties • High strength and high strength-to- As received Aged weight ratio solution annealed at 820°C 480 °C for 3 h • High notched strength very low C, tough and ductile fine, coherent intermetallic • M aintains high strength up to at least Fe-Ni martensitic matrix precipitates Ni 3 M o, Ni 3 Ti, 350°C • High impact toughness and plane strain fracture toughness High Fracture Ultra High Strength • Excellent weldability either in the Toughness UTS = 1800 M Pa annealed or aged conditions. Pre- heat K IC = 120 M Pa √m not required. • Good machinability. • Good castability.

Defence Laser- M IG hybrid welding process of 10mm thick M araging Steel plates M acrostructures Laser- GMAW hybrid welding process set up Single pass hybrid weld 3 pass M IG weld Process Fusion zone area Eyebrow zone width (sq.mm) from top to bottom of bead (mm) Hybrid 34.5 0.6 to 1.2 108.4 2 M IG

Defence Tensile properties of M 250 plate in different conditions Treatment 0.2% YS UTS, M Pa % El Fracture M Pa location Base metal as-received 862 970 18 Base metal Aged 1735 1750 10 1690 1850 LHW as welded 929 980 14 Base metal 817 930 M IG as welded 1035 1060 14 Base metal 911 1056 LHW PWHT 1590 1751 2 Weld 1643 1753 3 M IG PWHT 1575 1755 3 Weld 1650 1746 4.1

Aerospace Al-Li alloys Commercial Aluminum-Lithium Alloys Weldalite 049 Cu - 5.4, Li - 1.3, Ag - 0.4, M g - 0.4, Zr - 0.14 Alloy 2090 Cu - 2.7, Li - 2.2, Ag - 0.4, Zr - 0.12 Alloy 2091 Cu - 2.1, Li - 2.0, Zr - 0.10 Alloy 8090 Li - 2.45, Zr - 0.12, Cu - 1.3, M g - 0.95 http:/ / aluminumlithium.com/

Oil and Gas The offshore oil and gas industry is moving into deeper waters. Several issues arise: • The pipe wall thickness needs to be increased to resist hydrostatic collapse. • The pipelines may have to be laid by J-lay, instead of the more conventional S -lay method to reduce the weight supported by the laybarge. • The hydrocarbons are higher pressure and temperature and often containing a higher concentration of acid gases making the fluids more corrosive. In J-lay it is generally only possible to have a single welding station. Presently automatic gas welding is used but this has limitations. Higher Higher M ore M ore Higher well Higher well Welding Welding Strength Strength Corrosive Corrosive head head Challenges Challenges M aterials M aterials Environment Environment pressures pressures Emerging technologies High-Strength Steel Line Pipe: The use of higher strength steel requires less wall thickness for a given pipeline design or higher operating pressures for a pipeline design of a given wall thickness. Hybrid Welding Process: High efficiency lasers, which are becoming increasingly available, may make the use of hybrid welding processes feasible in the field. These processes are much more productive/ less labour intensive than even the most advanced mechanised welding systems. Seam tracking will be an integral part of this technology since the welding speeds are high.