Linear Porosity
Linear porosity is a chain-like arrangement of gas pores along the weld axis or fusion line. It causes high stresses and can lead to cracking.
Physical and chemical mechanism of action
Linear porosity forms when gas inclusions merge into a linear pattern along the weld or its edge. These gases can be released from the metal or filler during welding and become trapped as gas bubbles in the weld.
Metallurgical relevance & risks in welding
Linear porosity can cause high stresses, especially under mechanical load. These high stresses can lead to cracking and premature failure of the weld. In addition, it impairs the strength and toughness of the material.
Workshop practice & action instructions
To avoid linear porosity, it is important to do clean weld preparation. This includes proper cleaning and conditioning of the weld surfaces and using appropriate shielding. Also, let the weld cool completely before disturbing it to prevent gas bubbles. For highly stressed applications, special welding techniques or stabilizing filler materials may be recommended.