Round Rod in PTFE BR60 1000 mm natural

PTFE BR60 in round rod is PTFE with around 60 percent bronze powder, the maximum filler range for ordinary bronze compounds. The rod format makes the material easy to turn into bushings, thrust bearings, wear rings and packing components where load and sliding speed are combined. Against BR40 you gain higher compressive strength and less cold flow; against BR55 GR you gain a slightly cleaner bronze chemistry without graphite.

The bronze addition changes PTFE in several respects. The density goes up to around 4 g/cm3, cold flow drops sharply, compressive strength increases and dimensional stability under load becomes markedly better than in pure PTFE. At the same time the main thermal and chemical properties are kept largely intact. The service temperature stays between roughly minus 200 degrees and plus 260 degrees C continuously; the fire rating is V0. It is exactly the combination of pure PTFE chemistry and greatly improved mechanical properties that makes BR60 one of the most used materials for heavy PTFE seals.

Tribologically, PTFE BR60 works well as a dry running material under high load. Friction is low, if not the lowest in the PTFE family, and the bronze carries friction heat away effectively. That gives a high permitted PV value and makes the rod suitable for plain bearings in pumps, hydraulics, rotating shafts and compressors. Heat removal becomes particularly important in rotating bearings, where friction heat can otherwise build up close to the sliding surface. Chemically the material stands up to practically all industrial fluids, with a reservation for strong oxidizing acid, which can affect the bronze.

Typical parts are turned sliding bushings, wear rings, piston rings, thrust washers and support or guide rings in mechanical seals. The rod format is also practical for prototyping rotationally symmetric parts where the load is high and the tolerance demands tight. When broken or worn out metallic sealing parts in older machines are replaced, PTFE BR60 is often a good choice, since it can be turned out directly and the material both damps and seals better than hard metal against metal.

Machining is done with ordinary turning tools for engineering plastics, but since 60 percent bronze is fairly abrasive, coated carbide is recommended for large runs. A positive rake angle and light compressed air cooling give a fine surface and a stable dimension. Drilling and thread cutting work without trouble; threads in the material should be dimensioned for the high thermal expansion of the material, otherwise you risk the threaded section seizing or wearing as the temperature rises. In coarse diameters the center zone often releases internal stresses after the first rough cut; give the rod time to stabilize before the final dimension is taken.

Keep in mind that PTFE based composites move thermally more than most other plastics and considerably more than metal, so fits against steel shafts have to be adapted to the operating temperature. Mechanical fastening or press fit is the norm; the material cannot be welded or glued with conventional methods. In press fits in metal housings an initial diameter shrinkage usually settles stably even after heat cycling, as long as you have dimensioned with margin from the start. For rotating applications the mating surface should be hard and finely ground; a soft or rough mating surface accelerates the wear in the bronze particles and can give an unexpectedly short service life.

When a new BR60 bushing is run in, it pays to break the part in with a lighter load and moderate speed during the first operating cycle. That lets the material settle against the mating surface and form an even sliding film of PTFE and bronze. Round rod has to be stored cool and flat, since long rods can bend slightly over time because of the viscoelastic nature of the material. Protect cut faces against dirt if the material is going to be turned for sealing later; leftover dust and grease can otherwise be dragged into the surface on the first pass.

The 1000 mm round rod in natural is the heavier bronze version and is turned into bushings that have to carry high pressure.

Stocked diameters and lengths can vary; for special dimensions or ready cut blanks to drawing you send the dimension data directly and we come back with a proposal and a price. Do you need help choosing the right filler level and dimensioning the tolerance for your application? Get in touch and we compare BR40, BR55 GR and BR60 against the load and environment picture, and you get straight advice on which bronze content fits.