Types Of Welded Connections

WELDED CONNECCTION

INTRODUCTION

When two members are connected by means of welds, such a connection is known as welded connection. Welding offers an opportunity to the designer to achieve a more efficient use of the materials. Earlier designers considered welds as less fatigue resistant. It was believed that attaining good welds at site is impossible. Now a day, with the advances in the field of non destructive testing methods (NDT), testing and quality control of welds became easier. This gives the designers enough courage to explore the possibilities and capabilities of welded connections. Speedy construction is facilitated by using welded connections. Weight of welded connections is relatively low and hence cuts cost of construction. Since there is no reduction of holes the gross cross section is effective in carrying loads.

TYPES OF WELDED CONNECTIONS

The basic types of welded joints can be classified depending on the types of welds, position of welds and type of joint.

1. Based on the type of weld

Based on type of weld, welds can be classified in to fillet weld, groove weld (or butt weld), plug weld, slot weld, spot weld etc. Various types of welds are shown in Figure 15.

1.1. Groove welds (butt welds)

Groove welds (butt welds) and fillet welds are provided when the members to be joined are lined up. Groove welds are costlier since it requires edge preparation. Groove welds can be employed safely in heavily stressed members. Square butt welds are provided up to a plate thickness of 8mm only. Various types of butt welds are shown in Figure 16.

1.2. Fillet welds

Fillet welds are provided when two members to be jointed are in different planes. Since this situation occurs more frequently, fillet welds are more common than butt welds. Fillet welds are easier to make as it requires less surface preparation. Nevertheless, they are not as strong as the groove welds and cause concentration of stress. Fillet welds are preferred in lightly stressed members where stiffness rather than strength governs the design. The various types of fillet welds are shown in Figure 17.

1.3. Slot and plug welds

Slot and plug welds are used to supplement fillet welds where the required length of fillet weld cannot be achieved.

2. Based on the position of weld

Based on the position of weld, welds can be classified in to flat weld, horizontal weld, vertical weld, overhead well etc.

Based on the type of joints

Based on the type of joints, welds can be classified in to butt welded joints, lap welded joints, tee welded joints and corner welded joints.