All ASTM D3241 heater tubes are made from 6061-T6 aluminum that meets specific chemical composition limits outlined in ASTM D3241. The aluminum is drawn into tubing and machined to near final dimensions using high-precision CNC machines. Production tolerances are less than 0.0005 inch (0.01 mm).
The material and dimensions of Standard ASTM D3241 Heater Tubes comply with all of the requirements listed in ASTM D3241.
Standard ASTM D3241 Heater Tubes are finished using a patented process that produces an extremely high-quality surface finish on the heater tube. This finish meets the requirements of ASTM D3241.
Other heater tube manufacturers use mechanical polishing, which leaves scratches that are clearly visible under a microscope. These scratches diffuse light, making it more difficult to see changes in color on the surface of the heater tube.
The surface finish on Standard ASTM D3241 Heater Tubes is not scratched. This makes it more reflective, which makes it easy to detect changes in color on the surface, which is what ASTM D3241 is designed to do.