What is a common characteristic of active cutting oils?

Active cutting oils are designed specifically to enhance the machining process by reducing friction, improving surface finish, and extending tool life. A key characteristic of many active cutting oils is that they often contain sulfur compounds, which serve as extreme-pressure additives. These sulfur compounds form a protective film on the cutting tool and the workpiece, helping to withstand high temperatures and pressures encountered during machining operations.

Incorporating sulfur into cutting oils provides significant benefits, particularly in terms of lubrication under severe conditions, allowing for more efficient and effective machining processes. This characteristic is essential in applications where cutting tools and workpieces experience high loads, as it aids in preventing tool wear and improving overall performance.

While other options might touch upon aspects related to cutting oils, such as environmental considerations or specific applications, they do not encapsulate the defining chemical composition of active cutting oils like the presence of sulfur does.