Arc Length
Arc length is the distance between the electrode and the weld pool. A short gap causes hardening, porosity, and hot cracking; a long gap weakens the weld and can lead to embrittlement.
Physical-Chemical Mechanism of Action
Arc length affects the electrolyzation of the metal. A short distance increases temperature and hardening, which can lead to porosity and hot cracking. A long distance slows melting and can cause embrittlement and weakening of the weld.
Metallurgical Relevance & Risks in Welding
A too short arc length increases the risk of glass-hard martensite formation, leading to hot cracks and porosity. A too long arc length can cause embrittlement and weakening of the weld, reducing strength and toughness.
Workshop Practice & Instructions
For hard steels (e.g., HRC 30) use an arc length of 2 to 4 mm. For soft steels (e.g., HRC 25) set an arc length of 4 to 6 mm. If the material is unclear, adjust arc length slowly and check the structure.