Teknologi Dan Rekayasa PRINCIPLES OF WELDING

WELDING TERMS AND WELDING SYMBOLS Objective : After studying this unit the students can be able to : 1. identify the welding terms 2. explain the welding symbols. Teknologi dan Rekayasa

Welding Terms Welding is most often used in the form of a butt weld or a fillet weld, so we shall use these to show the most common welding terms. Fillet weld : two pieces of plate are joined together at right angles. Butt weld : two pieces of plate are joined together at 180°. Slot weld : two flat plates are joined with their edges overlapping. Plug weld : similar to a slot weld but uses a round hole of at least twice the thickness of metal being welded.

Welding Terms Parent metal : the metal on which the weld is deposited. Weld metal : the metal deposited by the electrode. Plate preparation : the way in which the plates are prepared before welding. Root gap : the gap between the vee prepared plates of a butt weld. Root face : a flat area filed or ground on the sharp edge of the vee preparation. Weld face : the outside face of the weld deposit.

Welding Terms 35° 90° Root face Root gap Weld face Reinforcement Penetration Throat thickness Parent metal Root gap Weld metal

Welding Terms Convex Mitre weld Fusion face Concave Parent metal Throat thickness Nominal throat thickness Convex Fusion zone Leg length Concave Fusion face Mitre weld Weld metal Reinforcement Parent metal

Welding Terms Penetration : In a butt weld the weld metal that flows through the root gap. In a fillet weld the weld metal that fuses into the corner where the two plates join is penetration. Fusion face : where the weld metal joins the parent metal. Leg length : the length of the fusion face in a fillet weld. Throat thickness : the actual distance from the root to the face of the weld. Reinforcement : in a butt weld is that metal on the face of the weld that is higher that the surrounding parent metal.

WELDING SYMBOLS A series of symbols have been standardized by the American Welding Society. Welding symbols uses in fabricating the required product and indicate to the welder the kind of weld, the location of weld and the size of the weld. Teknologi dan Rekayasa

Base of Weld Symbol The main foundation of the weld symbol is a reference line with an arrow at one end. The other data reflecting various characteristic of the weld by abbreviations, figure, and other line arrangements placed around the reference line. Teknologi dan Rekayasa

WELDING SYMBOLS A = angle F = finishing symbol L = length of weld S L – P A F R A = angle F = finishing symbol L = length of weld P = pitch of welds N = number of spots weld R = root S = size T = tail = field weld symbol = weld all around symbol = contour symbol = reference line = basic weld symbol Fig. 1. Standard location of element of welding symbol Teknologi dan Rekayasa

Designating types of welds The important factor in understanding weld symbol is recognizing the representations used for different types of welds. These welds are used on five basic kind of joints : butt, corner, lap, tee and edge. Welds are classified : fillet, plug or slot, spot, seam, and groove. Groove welds are further divided according to the particular shape of the groove joint. Each type of weld has its own specific symbol. For example, a fillet weld is designated by a right triangle, and a plug weld by a rectangle. Teknologi dan Rekayasa

WELDING SYMBOLS Fig. 2. Common types of weld Joints 1. Butt joint 3. Lap joint 2. Corner joint 4. Tee joint 5. Edge joint Fig. 2. Common types of weld Joints Teknologi dan Rekayasa

Location of Welds Another requirement in understanding weld symbols is the method which is used to specify on what side of a joint a weld is to be made. A weld is said to be either on the arrow or other side of a joint. The arrow side is the surface that is in direct line of vision, while the other side is the opposite surface of the joint. Weld location is designated by running the arrowhead of the reference line to the joint. The direction of the arrow is not important, that is, it can run on either side of joint and extend upward or downward. Teknologi dan Rekayasa 13

Location of Welds If the weld is to be made on the arrow side, the appropriate weld symbol is placed below the reference line. If the weld is to be located on the other side of the joint, the weld symbol is placed above the reference line. When both sides of the joint are to be welded, the same weld symbol appears above and below the reference line. The only exception to this practice of indicating weld location is in seam and spot welding. With seam or spot welds, the arrowhead is simply run to the centerline of the weld seam and the appropriate weld symbol placed above, below or astride the reference line. Teknologi dan Rekayasa 14

Location of Welds Information on weld symbols is place to read from left to right along the reference line in accordance with the usual conventions of drafting. Fillet, bevel and J-groove, flare-bevel groove, and corner-flange weld symbols are shown with the perpendicular leg always to the left. Teknologi dan Rekayasa 15

Basic arc and gas weld symbols Supplementary Symbols Weld Symbols (AWS) Fillet Plug or Slot Spot or projection Seam Back or Backing Melt Thru Surfacing Flange Edge Flange Corner Groove Square V Bevel U J Flare V Flare bevel Basic arc and gas weld symbols Weld all around Field Weld Contour Flush Convex Concave Supplementary Symbols Teknologi dan Rekayasa 16

Weld Symbols (AWS) Fig. 3. Side of a joint OTHER SIDE ARROW SIDE Teknologi dan Rekayasa

Fig. 4. Location of fillet weld Weld Symbols (AWS) OTHER SIDE ARROW SIDE BOTH SIDE Fig. 4. Location of fillet weld Teknologi dan Rekayasa

Combined Weld Symbols In the fabrication of product, there are occasions when more than one type of weld is to be made on a joint. Thus a joint may require both a fillet and double bevel groove weld.

Size of Welds There are several types of groove welds. Their size as shown in Fig. 5. The width of a fillet weld is shown to the left of the weld symbol and is expressed in fractions, decimals or millimeters. The other size of a fillet weld as shown in Fig. 6 Teknologi dan Rekayasa 20

Size of Welds Fig. 5. Size of groove weld 35° 1 70° 10 3 ARROW SIDE OTHER SIDE 35° 3 5 10 25° BOTH SIDE 35° 25° 3 10 5 Fig. 5. Size of groove weld Teknologi dan Rekayasa 21

Size of Welds Fig. 6. Size of fillet weld 10 100 100 SINGLE 10 10 100 DOUBLE 10 100 Fig. 6. Size of fillet weld

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