Lincoln Electric LTW2 manual Overhead Welding, Welding Sheet Metal, Hardfacing

Page 8

7

LEARNING TO STICK WELD

7

Overhead Welding

Various techniques are used for overhead welding. However, in the interest of simplicity for the inexperi- enced welder the following technique will probably take care of most of his needs for overhead welding:

1.Use 1/8" (3.2mm) at 90-105 amps or 3/32" (2.4mm) at 60 amps Fleetweld® 180 electrode.

2.Put the electrode in the holder so it sticks straight out.

3.Hold the electrode at an angle approximately 30° off vertical, both seen from the side and seen from the end.

The most important thing is to hold a VERY SHORT arc. (A long arc will result in falling molten metal; a short arc will make the metal stay.)

If necessary — and that is dictated by the looks of the molten puddle — a slight back and forth motion along the seam with the electrode will help prevent “dripping.”

Welding Sheet Metal

Welding sheet metal presents an additional problem. The thinness of the metal makes it very easy to burn through. Follow these few simple rules:

1.Hold a very short arc. (This prevents burn through, since beginners seem to hold too long an arc.)

2.Use 1/8” (3.2mm) or 3/32" (2.4mm) Fleetweld® 180 electrode.

3.Use low amperage. 75 amps for 1/8" (3.2mm) elec- trode, 40-60 amps for 3/32" (2.4mm) electrode.

4.Move fast. Don’t keep the heat on any given point too long. Keep going. Whip the electrode.

5.Use lap welds whenever possible. This doubles the thickness of the metal.

Hardfacing

There are several kinds of wear. The two most often encountered are:

1.Metal to Ground Wear.

(Plowshares, bulldozer blades, buckets, cultivator shares, and other metal parts moving in the soil.)

2.Metal to Metal Wear.

(Trunnions, shafts, rollers and idlers, crane and mine car wheels, etc.)

Each of these types of wear demands a different kind of hardsurfacing electrode.

When applying the proper electrode, the service life of the part will in most cases be more than double. For instance, hardsurfacing of plowshares results in 3-5 times more acreage plowed.

How to Hardface the Sharp Edge (Metal to Ground Wear)

1.Grind the share, approximately one inch (25mm) wide along the edge, so the metal is bright.

2.Place the share on an incline of approximately 20- 30°. The easiest way to do this is to put one end of the share on a brick. (See drawing.)

Most users will want to hardface the underside of the share, but some might find that the wear is on the top side. The important thing is to hardface the side that wears.

3.Use 1/8" (3.2mm) Wearshield™ ABR electrode at 90-105 amps. Strike the arc about one inch (25mm) from the sharp edge.

4.The bead should be put on with a weaving motion, and it should be 1/2” to 3/4" (12.5 to 19mm) wide. Do not let the arc blow over the edge, as that will dull the edge. (See drawing.)

5.Use the back-stepping method. Begin to weld 3" (75mm) from the heel of the share and weld to the heel. The second weld will begin 6" (150mm) from the heel, the third weld 9" (225mm) from the heel, etc.

BACK-STEPPING

Back-stepping greatly reduces the chances for crack- ing of the share, and it also greatly reduces possible warpage.

NOTE: The entire process is rather fast. Many begin- ners go much too slow when hardfacing plow shares, running the risk of burning through the thin metal.

Image 8
Contents Learning to Stick Weld LTW2 Table of Contents Learning to Stick Weld Arc-Welding CircuitCorrect Welding Position Correct Arc LengthPractice Correct Welding SpeedUse the following Do the followingJoint Types and Positions PenetrationButt Joints Fillet JointsMultiple Pass Welds Welding in the Vertical PositionVertical-Up Welding Vertical-Down WeldingHow to Hardface the Sharp Edge Metal to Ground Wear Overhead WeldingWelding Sheet Metal HardfacingHardfacing of Idler and Roller Metal to Metal Wear Welding Cast IronCast Iron Plate Preparation Contenido Circuito de la Soldadura al ArcoAprendiendo Palillo Soldar Aprendiendo a Palillo SoldarCircuito para soldadura de arco UNA Descarga Electrica puede ser mortalAdvertencia Posición correcta para soldarVelocidad correcta de avance PrácticaUtilice lo siguiente Realice lo siguienteTipos de soldadura PenetraciónSoldadura a tope Soldadura de fileteSoldaduras de pasadas múltiples Soldadura en posición verticalSoldadura en dirección vertical ascendente Soldadura vertical descendenteRecubrimiento duro Soldadura sobre cabezaSoldadura de hojas metálicas Como soldar hierro vaciado Preparación de una placa de hierro vaciado Pieza de respaldo de aceroTable DES Matières Apprenez À Coller Soudure Lapprentissage DU SoudageLe circuit de soudage à larc LES Chocs Électriques peuvent être mortelsLa bonne position de soudage La bonne longueur darcLa bonne vitesse de soudage PratiqueMatériel et réglage du courant Règles à suivreTypes de soudures PénétrationSoudures bout à bout Soudures dangleSoudures multipasses Soudage en position verticaleSoudage à la verticale en montant Soudage à la verticale en descendantSoudage au plafond Soudage de tôlesRechargement dur Comment recharger le tranchant usure métal-terreRecharger aux dimensions Soudage de la fontePréparation de la plaque en fonte