56 Modern Welding The drawing of a weldment seldom shows how the edges are to be prepared or how the completed weld appears. The drawing shows only how the parts come together and what type of joint they will form. Occasionally, when an unusual or very complex weld joint is to be made, a “detail” drawing of the joint may be drawn with the joint preparation and weld shape shown and dimensioned. Refer to Figure 3-1 for the types of welded joints and the types of welds used on the various joints. A complete welding symbol contains all the information about a welded joint. The welding symbol may appear in any view of the drawing. A welding symbol applies to only one joint and applies to that joint only until it changes direction. There are a few exceptions to this rule—they will be discussed later in this chapter. Some of the following information is given to the welder on the welding symbol: How to prepare the edges of the base metal prior to welding. What welding process to use. What type of weld to make. Where to place the weld. The size of the weld. The shape of the weld face. How to fi nish the weld surface after welding is completed. Much more information regarding the weld is also given on the welding symbol. Dimensions on a welding symbol may be in SI Metric units or US Customary units of measurement. Part of the complete welding symbol is the weld symbol, which shows what type of weld is to be placed in a joint. See Figure 3-21 for the position of the weld symbol within the overall welding symbol. Figure 3-22 shows the weld symbols used on an ANSI/AWS welding symbol. Information given in each part or area of the welding symbol will be explained in later paragraphs. A number of weld drawings, with their corresponding welding symbols, will be shown to illustrate the infor- mation given in the various areas of the complete welding symbol. The edges of the weld joint, as they would be prepared and fi tted up prior to welding, will be shown using hidden lines. A completed weld for the welding symbol will also be shown. 3.5.1 The Reference Line, Arrowhead, and Tail The reference line, shown in Figure 3-23, is always drawn as a horizontal line. It is placed on the drawing near the joint to be welded. All information to be given on the welding symbol is shown either above or below this horizontal reference line. Infor- mation given on a welding symbol is always shown in the same location, as indicated in Figure 3-21. The information is read from left to right whether it is above or below the reference line. The arrow may be drawn from either end of the reference line. The arrow always touches the line that represents the welded joint. The tail is used only when necessary. It may be used to give information on specifi cations, the welding process used, or other details required but not shown on the welding symbol. A number (such as 1, 2, or 3) may be used in the tail to refer the user to a note elsewhere on the drawing. A company may use Figure 3-20. These are the specifi cations for the AWS 4G or overhead groove welding position. The weld axis must be between and 80°. Look at View A. The weld face must be between and 80° or 280° and 360°. The weld is made from the lower side of the base metal. Weld axis 80°-280° 0°-80° 80° View A-A Weld face Weld axis View A-A Weld face
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