Round Rod in PTFE BR40 1000 mm natural

PTFE BR40 in round rod is a bronze filled PTFE compound where around 40 percent bronze is mixed into the polymer. The round rod is used mainly as a blank for turned parts, and the choice of BR40 in particular tends to land where you want the low friction and chemical resistance of PTFE, but where pure PTFE gets too soft or creeps too much under load.

The bronze powder changes the character of the material in several ways. The density goes up to around 3.9 g/cm3, cold flow drops markedly and compressive strength increases compared to pure PTFE. Mechanically the rod becomes stiffer and more dimensionally stable, which matters when you turn slim parts or run into a higher load level. At the same time the service temperature stays in the wide PTFE range, from around minus 200 degrees up to plus 260 degrees C continuously. The fire rating is V0. That means the rod handles both cryogenic operation and a hot process environment without leaving its character.

Chemically, PTFE BR40 is almost as resistant as pure PTFE, since the matrix is still fluoropolymer. The material resists practically all industrial fluids, solvents, acids and bases in normal use. The bronze can however be affected by strong oxidizing acid or concentrated salt solutions; in such media pure PTFE or PTFE GF is safer. Friction is low and the dry running properties good. The bronze also carries friction heat away, which lets the rod handle higher PV values than unblended PTFE and makes it better suited to moving load.

The round rod is used most often for turned plain bearings, sliding bushings, wear rings, piston rings, packing supports and sealing components in pumps, hydraulics and compressors. It is also useful for valve parts, guide rings in mechanical seals and wear surfaces in food and chemical handling equipment, where the combination of chemical resistance and wear resistance matters. Against pure PTFE you gain higher permitted load and less dimensional drift over time; against BR60 you gain slightly lower friction and a material that is a little kinder to tool edges.

Machining goes well with ordinary turning tools for plastic. Cutting edges with a positive rake angle give a clean cut, and light cooling with compressed air keeps the temperature down and reduces the risk of dimensional drift. The bronze makes tool wear increase somewhat compared to pure PTFE, so sharp carbide inserts are recommended, preferably coated for larger runs. Drilling, thread cutting and chamfering work without trouble. Rod in larger diameters should be relaxed a little after rough cutting to release internal stresses before the final dimension is taken.

Keep in mind that PTFE based materials move thermally more than most engineering plastics and considerably more than metal. With fits that have little clearance you have to allow for thermal expansion, especially if the working temperature varies over time. The material cannot be glued or welded in the conventional way; mechanical fastening, press fit or clamping is standard. In combination with metal shafts the mating surface should have an even and fine surface finish so that the bronze is not worn faster than necessary. A guideline is to keep the surface finish of the mating surface below Ra 0.4 micrometer for the best service life; rougher surfaces lead to accelerated wear in the bronze particles.

In the choice between BR40 and more heavily filled compounds it is usually pressure level and dimensional stability that decide. If the part sits under high and steady load for a long time and you do not want to see dimensional drift, the choice leans toward BR55 GR or BR60. If friction, machinability and a slightly kinder material character weigh heavier, BR40 is often enough. Round rod should be stored cool and flat; long rods that hang free risk bending over time because of the viscoelastic nature of the material. Protect cut ends against dirt if the material is going to be turned for sealing later.

The 1000 mm round rod in natural is turned into bushings and plain bearings that have to take pressure, thanks to the bronze in the material.

Stocked dimensions can vary; for specific diameters and lengths, or for cut blanks adapted to your drawing dimension, the easiest way is to send a drawing or your dimension requirements directly. We come back with a proposal and a price quickly without you having to go through the variant table. Do you need help choosing between BR40, BR55 GR or BR60 based on pressure level, sliding speed and temperature? Get in touch and we compare the alternatives against your application, and you get straight advice on which filler level fits best.