TUNGSTEN ELECTRODES - CBL-welding

1 Pink WC 10Wh te WZ 8i lB ue WL 20 GreenlBack WL 10rBown WZ 4y 0 Gre WC 2 Turquoi 2se WS WT 20 Red 10 YelWT low WT30 LilacWT 40 OragenTUNGSTEN ELECTRODESW2 Alloy elementsThorium oxidesZirkonium oxidesLanthan oxidesCerium oxidesThOZrOLaOCeO22232 Rare materials ?????????????????????Why TUNGSTEN alloys? To improve the fusion point To improve ignition properties To improve arc control To avoid contamination of weld pool3 TungstenChemical designation=W3 Density= g/cmFusion point= CBoiling point=6,000 CUnalloyed TUNGSTEN (Pure TUNGSTEN ) Designation = W Colour code= GreenAdvantages AC welding , fine arc controlDisadvantages DC welding . Very poor ignition properties and arc control Tendency towards dropping TUNGSTEN particles into the weld pool in connection with ignition4 Thorium alloy TUNGSTEN Designation= WT 10= - % thorium oxide Colour code= Yellow Designation= WT 20= - % thorium oxide Colour code= Red Designation= WT 30= - % thorium oxide Colour code= Lilac Designation= WT 40= - % thorium oxide Colour code= OrangeAdvantages DC welding When contents of Thorium oxide increase, electrical resistance will decline whereby the electron liberation will improve This improves ignition properties, lifetime and current load, at the same time the fusion point increases High fusion point (approx.)

2 3,600 C for WT 20)Disadvantages Poor ability to establish a shiny surface on the electrode point in traditional AC welding which means flickering arc. At the same time there is a tendency towards TUNGSTEN particles in the weld pool Tendency towards slagging in DC welding Not environmentally friendly since Thorium gives off radio activity during grinding of electrodes5 Zirconium alloy TUNGSTEN Designation= WZ 4 = - % zirconium oxide Colour code= Brown Designation= WZ 8 = - % zirconium oxide Colour code= WhiteAdvantages AC welding No dropping of TUNGSTEN particles into the weld poolDisadvantages Poorer ignition properties than pure TUNGSTEN ELECTRODES (W = green).6 Lanthan alloyTungsten Designation= WL 10 = - % lanthan oxide Colour code= Black Designation= WL 20 = - % lanthan oxide Colour code= BlueAdvantages Both AC and DC welding No tendency towards slagging Longer lifetime than WT ELECTRODES Produces a shiny surface in AC welding Higher fusion point than W- ELECTRODES (3600 C for WL 10) No dropping TUNGSTEN particles into the weld pool in connection with AC welding WL 10 (Lanthanated) cannot be loaded as much as WC (Ceriated) ELECTRODES as on ignition they start to drop TUNGSTEN particles into the weld pool, since they have a lower fusion point than WC alloy TUNGSTEN Designation= WC 10 = - % cerium oxide Colour code= Pink Designation= WC 20 = - % cerium oxide Colour code= GreyAdvantages Both AC and DC welding No tendency towards slagging Fine ignition propertiesDisadvantages DC welding causes more wear on ELECTRODES than WL 20 (blue)

3 8 TUNGSTEN alloy with rare materials Designation = WS 2 = ? % rare materials Colour code= TurquoiseAdvantages Both AC and DC welding Smaller tendency towards slagging than WT (Thoriated) AC welding produces a surface on the electrode pointDisadvantages No details on chemical content DC welding causes more wear on ELECTRODES than WL 20 (blue)shiny 9 Grinding of TungstenGrinding grooves must always follow the longitudinal direction of the disc10 Pointing anglesD smallerthan mmD largerthan mmApprox. 2D Approx. A small pointing angle gives a wide weld pool A large pointing angle gives a narrow weld pool Only for machine welding with Argon shielding mmFor machine welding it is an advantage to grind the electrode point in order to prolong the of TUNGSTEN electrodesBreaking a TUNGSTEN electrode by hand has always been forbidden. The electrode should always be cut or ground, a very slow and expensive process, however, which the welder has often turned his blind eye to.

4 That is why suppliers of ELECTRODES have tried to solve this , welders were always provided with unannealed TUNGSTEN ELECTRODES , which are very soft (flexible). Unfortunately, there will be longitudinal cracks if the electrode is broken, which will result in a very unstable and flickering arc. In recent years it has been possible to buy annealed TUNGSTEN ELECTRODES which, however, are very brittle and will easily fly to pieces if you break them. The ELECTRODES may even burst if you drop a storage cabinet with ELECTRODES on a concrete floor or the ELECTRODES are the most frequently sold type of electrode in Europe, and unless you specifically order unannealed TUNGSTEN ELECTRODES , you will be supplied with annealed period: week 52, 1997 Participants:Tests were carried out on standard AC/DC Niels-J rgen Christiansen, AMU Center, machines. Please note that test results (such Randersas current intensity, re-ignition properties Stig Jensen, Migatronic(HF), (ACt-balance), (ACi-balance), (current frequency) and (electrode preheating) may Tests were carried out to demonstrate be different if other welding machines and whether there are any types of TUNGSTEN shielding gases are available that can be used as alternatives to pure TUNGSTEN ELECTRODES for All AC tests were carried out on a AC welding and Thorium alloy TUNGSTEN Migatronic Commander with the following ELECTRODES for DC welding (the latter give settings:off a little radioactivity during grinding).)

5 ACt-balance:65%We also hoped to find a type of electrode ACi-balance:0 = neutralthat would be suitable for both AC and DC Frequency:50 Hzwelding which would allow welders to use Electrode preheating: 0 = neutraljust one type of ELECTRODES instead of two or three test method can be used by individual works for comparing two or more types of Tests were carried out with a view to TUNGSTEN ELECTRODES by using the welding demonstrating the difference between re-machines available and the current ignition properties and lifetimes (wear of intensities and other settings used for the ELECTRODES ) in the case of welding stainless relevant welding and aluminium with TUNGSTEN ELECTRODES of different alloys (see table).Lifetime and re-ignition properties of TUNGSTEN electrodes1617 CURRENT LOAD OF TUNGSTEN ELECTRODESW elding current: DC Gas: Argon 10 dia.: mmSlope up: 0 Slope down: 4 point: 20 Type of electrodeCommentsGreen: WPPure TungstenDrops the point at 100 : WT 202% Thorium oxideFusion at 180 : WT 404% Thorium oxideFusion at 180 : WC 202% Cerium oxideFusion at 180 : WL 101% Lanthan oxideFusion at 180 : WL 202% Lanthan oxideFusion at 180 : WS 2?

6 % Rare materialsDrops the point at 140 : WT 40 4% Thorium oxide. Load 240 ATurquoise: WS 2 ?% Rare materials. Load 280 ABlack: WL 10 1% Lanthan oxide. 280 ALoad Grey: WC 20 2% Cerium oxide. 280 ALoad Green: WP Pure TUNGSTEN . 200 ALoad Red: WT 20 2 % Thorium oxide. Load 260 ABlue: WL 20 2% Lanthan oxide. Load 240 AIllustration no. 118 welding current:AC 50 Hz Shielding gas:Argon Parent material:AIMg LOAD OF TUNGSTEN ELECTRODESW elding current: AC 50 HzGas: Argon 12 mat.: AIMg up: 0 Slope down: 4 point: 70 ACt: 65% -Electrode dia.: mmElec. dist. to workpiece: 3 mmType of electrodeCommentsBlue: WL 202% Lanthan oxideThe point forms a small, shiny ball at 150 ball with dia. like elec. is formed at 180 TUNGSTEN at 220 becomes unstable at 240 : WT 202% Thorium oxideThe point gets a coarse structure at 100 TUNGSTEN at 220 becomes unstable at 260 : WPPure TungstenThe point forms a small, shiny ball at 50 ball with dia.

7 Like elec. is formed at 80 ball gets a larger dia. than elec. at 140 TUNGSTEN at 200 becomes unstable at 200 : WC 202% Cerium oxideThe point forms a small, shiny ball at 100 ball with dia. like elec. is formed at 180 TUNGSTEN at 260 becomes unstable at 280 : WL 101% Lanthan oxideThe point forms a small, shiny ball at 100 ball with dia. like elec. is formed at 200 TUNGSTEN at 260 becomes unstable at 280 : WS 2? % Rare materialsThe point forms a small, shiny ball at 100 ball with dia. like elec. is formed at 160 TUNGSTEN at 260 becomes unstable at 280 : WT 404% Thorium oxideThe point forms a small, shiny ball at 100 point gets a coarse structure at 140 TUNGSTEN at 200 becomes unstable at 240 : WT 303% Thorium oxide(not illustrated)The point forms a small, shiny ball at 100 ball with dia. like elec. is formed at 160 TUNGSTEN at 260 becomes unstable at 260 illustration no. 120 Orange: WT 40 4% Thorium oxide.

8 Load 260 ATurquoise: WS 2 ?% Rare material. Load 220 ABlack: WL 10 1% Lanthan oxide. Load 220 AGrey: WC 20 2% Cerium oxide. Load 240 AGreen: WP Pure TUNGSTEN . Load 180 ARed: WT 20 2 % Thorium oxide. Load 260 AIllustration no. 2 welding current: AC 50 Hz Shielding gas: Ar/He 70/30 Parent material: AIMg LOAD OF TUNGSTEN ELECTRODESW elding current:AC 50 HzGas: Ar/He 70/30 12 mat.: AIMg up: 0 Slope down: 4 point: 70 ACt : 65% -Electrode dia.: to workpiece: 3 mmType of electrodeCommentsRed: WT 202% Thorium oxideThe point gets a coarse structure at 80 ball with dia. like elec. is formed at 140 down on one side at 200 TUNGSTEN at 260 becomes unstable at 260 : WPPure TungstenThe point forms a small ball at 30 ball with dia. like elec. is formed at 60 ball gets a larger dia. than elec. at 100 TUNGSTEN at 180 becomes unstable at 180 : WC 202% Cerium oxideThe point forms a small ball at 90 ball with dia. like elec.

9 Is formed at 160 ball does not get a larger dia. than TUNGSTEN at 220 becomes unstable at 240 : WL 101% Lanthan oxideThe point forms a small ball at 80 ball with dia. like elec. is formed at 160 ball does not get a larger dia. than TUNGSTEN at 220 becomes unstable at 220 : WS 2? % Rare materialsThe point forms a small ball at 80 ball with dia. like elec. is formed at 160 ball does not get a larger dia. than TUNGSTEN at 220 becomes unstable at 220 : WT 404% Thorium oxideThe point gets a coarse structure at 80 ball with dia. like elec. is formed at 140 down on one side at 220 TUNGSTEN at 260 becomes unstable at 260 : WL 202% Lanthan oxide(not illustrated)The point forms a small ball at 70 ball with dia. like elec. is formed at 130 ball does not get a larger dia. than TUNGSTEN at 200 becomes unstable at 240 illustration no. 222 Orange: WT 40 4% Thorium oxideTurquoise: WS 2 ?% Rare materialsBlack: WL 10 1% Lanthan oxideGrey: WC 20 2% Cerium oxideGreen: WP Pure TungstenRed: WT 20 2 % Thorium oxideBlue: WL 20 2% Lanthan oxideIllustration no.

10 3 welding current:AC 200 A 50 Hz Shielding gas: Argon Parent material:AIMg 2,5 Load: 50 re-ignitions at 200 A23 TUNGSTEN re-ignition propertiesMIGATRONIC COMMANDER 320 AC/DCWelding current: AC 200 A 50 HzShielding gas: ArgonParent mat.: AIMg of electrodeAfter 10ignitionsAfter 20ignitionsAfter 30ignitionsAfter 40ignitionsAfter 50ignitionsTotalevalua-tionCommentsBlue: WL 202% LanthanFIFIFIFIFIF+Very fine ignition, produces a shiny ball withthe same dia. as the electrode was tested at 180 amp, because thepeak load is lower than for other : WT 202% ThoriumFIFI/DTFS tops after 20 ignitions, since large quantities ofTungsten are dropped into the weld pool. Verycoarse structure of the point after a few : WPPure TungstenFIFIFIFIFIF+Very fine ignition, but produces a shiny andvibrating ball much larger than the electrodediameter. The reason may be the almostmaximum load of the : WC 202% CeriumFIFIFIFIFIFFine ignition, produces a shiny ball which is a little larger than the electrode diameter, but alittle : WL 101% LanthanFIFIFIFIFIFFine ignition, produces a shiny ball which is a little larger than the electrode diameter, but alittle :WS 2?