What is Complete Joint Penetration Weld in Welding?

Complete Joint Penetration Weld (CJP) is a type of welding in which weld metal extends through the joint thickness. This results in a strong, high-strength weld that is resistant to cracking and failure. CJP welds are often used in critical applications where strength and reliability are paramount. In addition to their high strength, CJP welds also have excellent fatigue resistance and can withstand repeated loads without failing.

CJP welds are typically made using a welding process called gas tungsten arc welding (GTAW). This process uses an electrically charged tungsten electrode to produce an arc between the electrode and the workpiece. The resulting heat from the arc melts the base metals and allows the filler metal to flow into the joint.

CJP welds are usually made in multiple passes, with each pass depositing a layer of weld metal. The number of passes required depends on the thickness of the materials being joined. Thinner materials may only require one or two passes, while thicker materials may require three or more passes.

The main advantage of CJP welds is their high strength and reliability.
However, they do have some disadvantages. One is that they can be difficult to make in tight spaces or on complex shapes. Another is that they generally require more time and effort to produce than other types of welds.

What is the difference between a complete joint penetration and partial joint penetration?

Complete Joint Penetration (CJP) welds are made with weld metal extending through the entire thickness of the joint. Partial Joint Penetration (PJP) welds are made with weld metal that does not extend all the way through the thickness of the joint.

CJP welds are typically stronger and more reliable than PJP welds, but they can be more difficult to make in tight spaces or on complex shapes. PJP welds are generally easier to make than CJP welds, but they are not as strong or reliable.

The complete joint penetration weld symbol

The main difference between a complete joint penetration weld and a partial joint penetration weld is that CJP welds are made with weld metal extending through the entire thickness of the join, whereas PJP welds only have weld metal partially penetrating the thickness of the join.