The most common way, is to strategically place some small welds along the joint to hold the joint in alignment during the welding process. These are known as tack welds. It is normal to tack weld every welded joint you attempt. Note: The thinner your parent metal is the more tack welds you will need. Set up and clamp the two pieces into a T shape. Tack weld the two ends of the T-joint.
Use the leftwards technique to weld the joint. Look at the angle of the welding torch. The leftwards technique means that the torch is pushed along the joint during welding or the gas pocket is always ahead of the welding wire. The direction of travel is right to left. For left handed people, the direction of travel will be left to right with the gas pocket also ahead of the welding wire.
After welding use an angle grinder and sanding pad to remove localised spatter. If you need to re-paint the welded area ensure that the joint and adjacent materials have cooled down completely. Joint Preparation. How to : Essentially, you need to weld metal that is not heavily rusted, covered in paint, grease or oil. What do you need to start welding? Remove the mill scale using a sanding pad and angle grinder from the joint faces.
Click here for more Welding Supplies. When an intermittent fillet is not a chain weld it will then be called out as a staggered intermittent fillet weld. The welds will be placed on both sides of the joint but it will be offset with one another. This offset shows on the reference line as well. It could be staggered in either direction on the reference line. Dimensions of these welds must be specified on both sides of the reference line.
If the weld is only to be intermittent on one side and a continuous weld on the other the symbol must be dimensioned individually. Not all pitch will be the same, or necessarily common space. You must be able to calculate the spacing between weld stops and weld starts in order to apply the correct welds to the specification.
An easy way to find this distance is simply subtract the pitch from the weld length segment. At times there will be a mixture of continuous welding as well as intermittent welding. If this occurs the spacing between these segments will all be the same.
If this combination occurs welding symbols should specify continuous and intermittent on the same side of the joint. These are also often dimensioned. Write down the corresponding information with each letter and specify what it is.
Skip to content Fillet welds are one of the most common weld types in the industry. Fillet Weld Quiz Write down the corresponding information with each letter and specify what it is. Previous: Supplementary Welding Symbols.
Next: Groove Welding Symbols. The stem of the arrow should not be a horizontal line on the drawing. The side of the joint to which the arrow points is, by definition, the "arrow side" of the joint, and the opposite side of the joint is the "other side" of the joint Figure 1. Often only limited space is available on a drawing for welding symbols. To minimize the number of welding symbols required, it is permissible to use more than one arrow in a single welding symbol if each joint to which an arrow is pointing is to be welded in exactly the same way.
Since a welding symbol specifies welding of only the joint to which an arrow is pointing, and a change of direction or change in geometry constitutes the end of a joint, a multiple arrow welding symbol can be very helpful, particularly around closed corners Figure 2.
The Reference Line Another essential part of all welding symbols is the reference line, which is a straight line, drawn horizontally on a drawing, and connected to the arrow. The arrow may be connected to either end of the reference line Figure 1. Information relating to the "arrow side" of the joint is placed below the reference line and information relating to the "other side" of the joint is placed above the reference line.
These positional relationships exist whether the arrow is attached to the left or right end of the reference line, and do not change as the angle between the arrow and the reference line varies Figure 1. The sequence of operations necessary to produce a specified weld is not indicated by the normal single-reference-line welding symbol. For example, if welding is to be done on both the "arrow" and "other" sides of a joint typically called a double weld , a single-reference-line welding symbol does not specify which side of the joint is to be welded first.
In fact, the symbol does not specify completion of the welding from one side prior to the start of the welding on the opposite side. These details are normally left to the personnel interpreting the welding symbol, with the requirements of the completed weld specified by the symbol.
If the sequence of operations needs to be specified, a multiple-reference-line welding symbol may be used. Two or more reference lines may be connected to the same arrow, with the reference line closest to the arrow specifying the first operation, followed by the operations specified by the sequence of reference lines reading upward or downward from the arrow Figure 3.
It should be noted that operations other than welding, such as nondestructive examinations, can be specified by a multiple-reference-line symbol. The Tail A third element to be considered is the "tail" of the welding symbol. Information for which there is no specific provision elsewhere in the symbol is placed to the left or right of the tail as appropriate. Reference to the approved welding procedure specification WPS is an example of information appropriate in the tail of a welding symbol.
Since a WPS can contain all of the details applicable to a specific joint, a welding symbol composed of an arrow, reference line, tail and applicable WPS designation would be sufficient to completely specify the welding of the joint.
The welding process to be used is often specified by entering process designation letters in the tail of the welding symbol. The American standard includes two lists of processes and their corresponding designation letters. Table 1 groups similar processes, such as arc welding, brazing, resistance welding, and thermal cutting, while Table 2 arranges the processes alphabetically.
Groove Welds Additional information may be included in a welding symbol, even if also included in a WPS. For example, V-, U-, bevel-, or J-groove welds may be specified to provide increased weld size in a given joint, compared to that obtainable with a square-groove weld. The choice is usually made on the basis of cost for the completed weld.
A groove-weld symbol may be added to a welding symbol, below the reference line, to specify a weld only on the "arrow side" of the joint single weld ; above the reference line, to specify a weld only on the "other side" of the joint also a single weld ; or weld symbols may be added both below and above the reference line, to specify a double weld Figure 4.
Complete Joint Penetration Since many applications require welds providing complete joint penetration CJP , there are several ways to specify this condition. One way is to use an arrow, a reference line, and add CJP in the tail of the symbol. This symbol specifies complete joint penetration with no detail as to how the final condition is to be achieved.
Such a symbol may be appropriate when there is uncertainty as to what specific equipment will be available when the work is to go through the shop. Later, when equipment availability is known, it is a good practice to submit assembly drawings to engineering for final approval, with welding symbols containing all pertinent details. A second way to specify complete joint penetration is to include a single groove-weld symbol or double groove-weld symbols must be the same weld symbol on both sides of the reference line , without any dimensions to indicate depth of bevel or weld size.
It should be noted that partial joint penetration can be specified by adding the depth-of-bevel dimension and the required weld size in parentheses to the left of the groove-weld symbol or both symbols of a double weld Figure 5. Inclusion of a backing weld symbol or back-weld-symbol, opposite a groove-weld symbol, specifies complete joint penetration if no depth-of-bevel or weld-size dimensions are added.
Also, the inclusion of a backing symbol, opposite a groove-weld symbol, again without depth-of-bevel or weld-size dimensions, specifies complete joint penetration Figure 6. Although there are provisions for specifying the root opening gap , groove angle, and finish contours of welds, it is suggested that these details are best specified by a shop standard.
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