Boston Gear SB4 Plain Sleeve Bearings
The 841 bronze round rod is sintered, meets American Society for Testing and Materials International ASTM B438-73, Society of Automotive Engineers SAE 841, and United States Military Standard MIL-SPEC B-5687C specifications, and has a standard tolerance. The 841 bronze alloy, also known as oil-impregnated bronze, contains oil for high wear resistance and self-lubrication. The material has been sintered for consistent mechanical properties throughout.
Copper, brass, and bronze are known as red metals because they contain copper, which has a reddish color. Copper, a term that applies to alloys containing at least 99.3% copper, offers very high thermal and electrical conductivity and provides corrosion resistance, formability, and machinability. Brass is an alloy of copper and varying levels of zinc, sometimes with additional elements. It provides greater strength and better machinability than copper or bronze. Bronze is commonly an alloy of copper and tin, but sometimes it is copper alloyed with other elements such as aluminum, phosphorus, manganese, or silicon. Tin gives bronze more corrosion resistance than brass and greater strength than copper. Copper and its alloys have temper designations, meaning the material has undergone a process to achieve certain properties of strength and hardness.
Tensile strength, used to indicate the material's overall strength, is the peak stress it can withstand before it breaks. Corrosion resistance describes the material's ability to prevent deterioration caused by atmosphere, moisture, or other medium. Wear resistance indicates the ability to prevent surface damage caused by contact with other surfaces. Hardness (commonly measured as indentation hardness) describes its resistance to permanent surface deformation. Formability indicates how easily the material can be permanently shaped. Machinability describes how easily it can be cut, shaped, finished, or otherwise machined, while weldability characterizes the ability to be welded.