Flux cored Arc Welding- a productive process

1 flux cored Arc welding - a productive process Abby Joseph, voestalpine Bohler welding India CII welding Conference 2016, Mumbai- 16 Nov 2016. voestalpine B hler welding voestalpine B hler welding Market overview and trends cored wire annual growth rate 6-8%. [kto] Global growth cored wires Shift from stick electrodes to cored wire and solid wire 395. Higher deposition rate, (23%). cored wire also applicable for positional welding Ease to use MIG/MAG equipment and gases getting cheaper Source: figure 2013 from BM; growth rate from F&S. voestalpine B hler welding Market overview Indian scenario Highlights 1. Joining FCWs have a total market of 10,000MT/yr.

2 And HF FCWs 2500MT/yr. 2. Industry segments- Pre-engineered buildings, Railways, Shipbuilding. 3. Structural steel joining is an early adopter of FCAW process , although SMAW still has a significant share. 4. FCAW has a good position in SS- mainly for cladding but also for high-thickness joining. 5. Oil & Gas segment has adopted FCAW utilizing the new features of low-H2, CTOD and NACE compliance. 6. LNG Tank construction use Ni-base FCWs for higher productivity in V-up welding voestalpine B hler welding What is FCAW? Principle of FCAW process Slag systems Parameter settings Economical Aspects welding techniques Wire production & QA/QC. voestalpine B hler welding flux cored Arc welding (FCAW).

3 Operating principle of the process voestalpine B hler welding Slag System With respect to the flux ingredients, the flux cored wire may be rutile based or basic based. Rutile gives good slag detachability whereas basic gives good mechanical properties. In rutile flux ingredients, the slag may be fast freezing or slow freezing. voestalpine B hler welding welding Techniques Pushing Neutral Dragging voestalpine B hler welding Production of folded cored wires voestalpine B hler welding Production of seamless cored wires Metal strip Manufacturing tube from solid strip using HF welding Annealing and calibrating to filling Drawing to final dimension diameter and copper coating Manufacturing agglomerated flux and Pre-drawing to annealing filling of the tube by diameter and annealing vibration of the filled tube voestalpine B hler welding Quality Assurance voestalpine B hler welding Quality Assurance Free for shipment Stopped for further Investigation voestalpine B hler

4 welding Types of cored wires Division by the filling cored wires for gas shielded welding Self-Shielded without slag slag formation Joining Hard facing M B rutile filler metal cored wires basic filler R P. slow freezing slag fast freezing slag voestalpine B hler welding Types of cored wires Division by production methods Seamless cored Wires Folded cored Wires Thicker tube (metallic coat) Higher filling ratio optimal positioning of the wire easier to optimize weldability for automatic welding 100% copper coated 100% homogenous filling best current transition uniform mechanical properties and corrosion resistance low hydrogen content in closed tube lower deformation in production no re-drying necessary enables production of high alloyed and nickel base qualities voestalpine B hler welding Equipment, Arc Types and welding Positions Main Components of the welding Machine voestalpine B hler welding Welder skill requirement Comparatively lower 1.

5 Semi-automatic process 2. CV against CC power source characteristics leads to nearly constant arc gap. 3. Much wider parameter window within the same dia. of wire lead to a lot of flexibility. 4. Advances in equipment/systems helps welder in self-correction while welding . 5. Modern equipment (programmable) helps welder in replicating the performance. 6. Less welder fatigue ensures consistent performance over long working hours Skilled Welders + Advanced FCAW power source = Less repair and high productivity voestalpine B hler welding High Deposition Efficiency Weight of Weld Metal Deposition efficiency =. Weight of Electrode Used For FCAW: 85-90 %.

6 For SMAW: 55-60%. flux cored wires have a lower flux -to-metal ratio than coated electrodes, and thereby, a higher deposition efficiency. voestalpine B hler welding Main properties of cored wires process efficiency Gives information about the efficiency of the process [%]. Solid wire FCAW. Current transfer Current transfer Cross section Cross section flux Isolator Weight Minus spatter, Weight Average Consumable wire slag etc. Weldmetal process - wire- : 1,2 mm [g/m] [g/m] [g/m] efficiency Solid wire 8,68 -0,19 ..= 8,49 (98%) 98 100 %. Metal cored 8,30 -0,22 = 8,08 (97%) 96 98 %. Basic 7,48 -0,43 = 7,05 (94%) 85 94 %. Rutile 7,22 -0,85 = 6,37 (88%) 83 92 %.

7 Voestalpine B hler welding Higher Operating Factor %age of a welder's working day that Arc Time (Hours). =. is actually spent welding Total Hours Worked SMAW 15% to 40% FCAW 40% to 50%. Because of Lesser ARC Time Because of Higher ARC Time Operating factors ranging from 50% to values approaching 90% may be obtained depending on the degree of automation. Operating factor depends upon, Machine set-up (electrode change, holder adjustment). Operator Skill Material Handling voestalpine B hler welding Higher Current density Current density J [A/mm ] is the relation between the amperage I [A] and effective cross section A [mm ] of the wire: I I I A. J 2 [ ].

8 A d (da di2 ) * mm . 4 4. Solid wire FCAW. Current transfer Cross section Current transfer Cross section d da di flux Isolator voestalpine B hler welding Main properties of cored wires Current density Solid wire, 1,2 mm welding current I = 220 A. Shielding gas: M21 (18% CO2 + 82% Ar). I 220 . J1= = = 194. d p (1,2mm) p mm . 4 4. Rutile flux cored wire, 1,2 mm welding current I = 220 A. Shielding gas: M21 (18% CO2 + 82% Ar). I 220 A . J2= = = 320. (d -d ). a i p (1,2 -0,75 )mm p mm . 4 4. Higher current density = Higher deposition rate voestalpine B hler welding Penetration compared to solid wire flux cored wire have a wider arc Operate therefore with a very safe penetration The risk of lack of fusion is minimized flux cored Solid wire voestalpine B hler welding cored wires welding parameters More flexible welding parameter settings 38.

9 Spatter formation 36. Solid wire . Steady low spatter welding in 34 mm spray arc from approx. 150 A, 32. Voltage (V). flux - 24V, m/min. (solid wire 30 cored wire mm from approx. 210 A, 28 mm 28V, 7 m/min) 26 Solid wire . mm Good welding behavior 24 flux - cored remains constant over wide 22 wire mm range of currents and voltages 20 Poor seam outflow 18. 100 150 200 250 300. Current (A). voestalpine B hler welding Comparison of deposition rates flux cored wire 0,9 mm Theoretical deposition rate flux cored wire 1,2 mm flux cored wire 1,6 mm Solid wire 1,0 mm 100% (kg/h). Solid wire 1,2 mm Coated electrode welding position: 1G PA. Amperage (A). voestalpine B hler welding Comparison of weld length flux - cored wire Solid wire flux cored wire Covered electrode E316LT1-4(1) E316L-(Si) A = 180.

10 E316L-17. EAS 4 PW-FD EAS 4 M-IG (Si). FOX EAS 4 M-A V= 27,5. 1,2 mm 1,0 mm 3,2 mm WS = 8,3 m/min M 21 M 12. [cm] L = 220 mm/min [cm]. 30 30. Solid wire pulsed [cm]. 25 30 25 A = 100. 25. V = 20. 20 20. WS = 5,5 m/min 20. 15 15 L = 145 mm/min 15. 10 10 Covered electrode 10. A = 90. 5 5. 5 V = 26. 0 0 0 L = 75 mm/min voestalpine B hler welding Fabrication Codes & FCAW process AWS FCAW process is deemed as qualified processes as per Section . Prequalification of WPS. With respect to welder qualification, a 3G qualification qualifies for all other positions except Overhead position. ASME SEC IX. QW-255 covers the welding variables for procedure qualification for GMAW and FCAW.