Lead Lubrication Effect
Lead lubrication effect: Embedding lead particles in alloys to improve machinability and emergency running properties, with soft particles acting as solid lubricants.
Physical-Chemical Mechanism of Action
Lead lubrication effect: Lead particles are embedded in the alloy to improve its machinability and emergency running properties. These soft particles act as a lubricant and reduce friction between the grains of the metal alloy.
Metallurgical Relevance & Risks in Welding
The lead lubrication effect can be used in the production of free-machining steels or emergency running steels. However, if the lead concentration is too high, the microstructure can be contaminated and strength impaired, leading to cracks and damage.
Workshop Practice & Instructions
To utilize the lead lubrication effect, a small amount of lead (approx. 0.1-0.5%) should be embedded in the alloy. The temperature and cooling time must be carefully controlled to achieve the optimal microstructure. If cooling is too fast or too slow, the lead will not be properly distributed, resulting in negative properties.