Teknologi Dan Rekayasa SHIELDED METAL ARC WELDING ADVANCE (SMAW) ADVANCE

Teknologi dan Rekayasa WELDING TECHNIQUE OF SMAW  OBJECTIVE : After studying this lesson, the students can be to : 1.list name the various of welding positions 2.explain the basic types of welding joints 3.explain the welding technique of shielded metal arc welding.

Welding position : Shielded metal arc welding can be performed in various positions such as horizontal, flat, vertical and overhead. Teknologi dan Rekayasa WELDING TECHNIQUE OF SMAW

Teknologi dan Rekayasa HorizontalFlat Overhead Vertical Fig. 1. Four basic welding positions WELDING TECHNIQUE OF SMAW

Teknologi dan Rekayasa Fig. 2. Welding position diagram WELDING TECHNIQUE OF SMAW

Types of Joints : The basic types of joints used in joining metal product are : 1.Butt joint 2.Corner joint 3.Lap joint 4.Fillet T joint Teknologi dan Rekayasa WELDING TECHNIQUE OF SMAW

Fig. 3. Type of Joining Teknologi dan Rekayasa 1. Butt joint3. Lap joint 2. Corner joint 4. Tee joint WELDING TECHNIQUE OF SMAW

Starting the arc :  Generation of the arc is accomplished by tapping or scratching the end of the electrode on the work piece.  Usually the tapping method is used for DC welding machines, and the scratching method is used for AC welding machines Teknologi dan Rekayasa WELDING TECHNIQUE OF SMAW

Fig. 4. Two method of starting the arc Teknologi dan Rekayasa start finish arc length TAPPING METHOD plate start finis h arc length plate SCRATCHING METHOD WELDING TECHNIQUE OF SMAW

Current setting : The amount of current to be used depends upon the thickness of the metal to be welded and the actual position of welding. Higher current and larger diameter electrodes can be used for welding in flat positions than in vertical or overhead welding. Electrode diameter is governed by the thickness of the plate and welding position. Teknologi dan Rekayasa WELDING TECHNIQUE OF SMAW

Arc length : The length of the arc depends on the type of electrode used and the kind of welding done. Generally, the length of the arc should be approximately equal to the diameter of the electrode. Teknologi dan Rekayasa WELDING TECHNIQUE OF SMAW

Travel speed : Travel speed is the rate the electrode travels along the weld seam. The maximum speed of welding is influenced by the skill of the operator, the position of the weld, the type of electrode, and the required joint penetration. Teknologi dan Rekayasa WELDING TECHNIQUE OF SMAW

Electrode Position :  The angular position of the electrode has a direct influence in the quality of weld made. The two guiding considerations of electrode position are lead angle and work angle.  Lead angle is the angle between the joint and the electrode when viewed in a longitudinal plane. Work angle is the angle between the electrode and the work when viewed from an end plane Teknologi dan Rekayasa WELDING TECHNIQUE OF SMAW

Fig. 5. Electrode Position Teknologi dan Rekayasa Lead angle Work angle WELDING TECHNIQUE OF SMAW

Fig. 6. Electrode position for flat and horizontal Teknologi dan Rekayasa  85  90   WELDING TECHNIQUE OF SMAW

Fig.7. Electrode position for vertical and overhead Teknologi dan Rekayasa 90   90   WELDING TECHNIQUE OF SMAW

Teknologi dan Rekayasa