Sheet in PTFE BR55 GR 1000x1000 mm natural

PTFE BR55 GR in sheet is a bronze filled PTFE compound with graphite added. About 55 percent bronze gives the material heavily increased wear resistance and compressive strength compared with pure PTFE, and the graphite lowers friction further while dry running properties improve. The sheet is intended for applications where you mill or turn out parts that have to work under load and at high sliding speed, and the bronze plus graphite combination is one of the most used for demanding sealing and sliding components.

The core of the material is still fluoropolymer. That means a wide service temperature range, from about minus 200 degrees up to plus 260 degrees C continuously, and fire rating V0. Density is high, around 4 g/cm3 depending on the exact filler content. The bronze and the graphite cut cold flow markedly, and compressive strength is among the highest a PTFE compound can offer. The sheet takes seasonal temperature swings without losing dimensions the way pure PTFE does, and dimensional stability under varying load is one of the most important reasons to pick BR55 GR over softer grades.

Chemically the base matrix is still PTFE and stands up to practically all industrial chemicals, solvents and process fluids. The bronze filler is sensitive to strongly oxidizing acid or concentrated salt solutions, though, so for those media you are better off with pure PTFE or PTFE GF. The graphite makes the material electrically semiconductive, which is worth thinking about in applications where static buildup is a problem. It also adds to the self lubricating character: together with the bronze it gives a tribological system that takes both high sliding speed and high surface pressure without external lubrication.

The sheet format typically goes to machined wear strips, slide plates, thrust bearings, contact rollers, piston skirt rings and large gasket parts. The material sits in pumps, compressors, hydraulic valves, agitators, rotary actuators and industrial ancillary equipment where load and sliding speed come together. For machine builders who need to cut out specially shaped wear surfaces, the sheet format is often more practical than rod, since you can machine long rectangular parts flat out of a single piece without welding or mechanical joining.

Machining goes well with ordinary cutting tools for engineering plastics, but since the bronze content and the graphite are harder than the polymer, the material wears on the cutting edges. Carbide is standard, preferably coated. Ripping, milling and turning work with a positive rake angle and light cooling with compressed air. Abrasive finishing gives a fine surface, and the sheet can be faced to very tight tolerances. For larger runs, diamond coated tools are a good option for keeping tool changes down.

PTFE based materials have high thermal expansion, so tolerance calculations for fits and clamping should take operating temperature into account. The material is not glueable or weldable in the conventional way; mechanical fastening or clamping is standard. For larger wear surfaces against machine frames, through bolts with washers and moderate preload usually work best; for narrow slide strips, sticking them down with double sided industrial tape for testing is a quick way to verify the fit before the final bolting. Long straight wear strips take a light preload from the bolt forces without deforming, which lets the fits settle after a few duty cycles.

Things to weigh when choosing: pure PTFE or PTFE GF is preferable if the medium is aggressively oxidizing and the bronze risks corroding, and also if electrical insulation is required. BR55 GR is preferable if the PV value is high, if dry running properties are decisive and if some electrical dissipation is wanted, for example in applications with static buildup. Sheet thickness should be picked so that every cutting direction has plenty of material; very thin sheets under a few millimeters can be sensitive to flatness and to stresses in the edge cut, and thicker sheets usually release better in heavier part machining.

At 1000x1000 mm in natural the sheet is enough for sliding surfaces that have to carry pressure and lubricate themselves dry at the same time, thanks to both bronze and graphite in the material.

Stocked thicknesses and sheet sizes vary; for specific thicknesses outside standard, or for parts cut to drawing, the simplest way is to send the dimensions straight over. Do you need to compare BR55 GR against plain bronze compounds, against PTFE GF or against graphite filled PTFE without bronze in your application? Get in touch and we will go through load data, chemical environment and ambient conditions together, and you get a straight answer on which composition fits best.