Learning Objectives After studying this chapter, you will be able to: Identify the fi ve basic welding joints. Identify and describe the various welds that may be used in each welding joint. Label the parts or areas of a grooved butt weld and a fi llet weld. Locate and apply required weld and joint information from an AWS welding symbol. List and describe the four welding positions. The fi eld of welding uses standardized termi- nology to describe the various welding joints and welding positions that every welder must know. This chapter will introduce and explain many essential welding vocabulary terms. Also, when a welder is given a mechanical drawing, he or she needs to be able to understand the type and location of the welds to be made by reading the welding symbols. This chapter will also explain how to read and understand the meaning of AWS welding symbols. 3.1 Basic Weld Joints A weld joint refers to how the parts to be joined are assembled prior to welding. There are fi ve basic types of joints used in welding: butt, lap, corner, T-, and edge. See Figure 3-1. The metal to be joined is called the base metal. If the part to be welded is not metal, it is called base mate- rial. It is also known as the workpiece or work. The edges of the base metal are often machined, sheared, gouged, fl ame cut, or bent to prepare them for welding. Weld joint design and metal thickness usually deter- mine how the joint is prepared. Generally, the weld joint design is determined by an engineer. 3.1.1 Butt Joint Butt joints are used when parts are joined edge- to-edge. Common examples of butt joints are the deck plates on a ship or the pipes of an oil pipeline. Both are assembled end-to-end. There are a variety of butt joint confi gurations, depending on how the ends of the pieces being joined are prepared. For quality welds to be produced on butt joints, the edges of the base metal often require special preparation before welding. 45