Chemraz® O-Rings

What Chemraz is

Greene Tweed makes Chemraz for chemical processing, refining, oil and gas, semiconductor and life-science equipment. It is a full perfluoroelastomer: the polymer chain carries fluorine where an ordinary rubber carries hydrogen, which is what lets it sit in ketones, amines, hot caustic and steam that swell or harden FKM. The line splits into the same families as every FFKM maker's, a universal grade, a high-temperature grade, a steam grade and a high-hardness grade for gas decompression, each with its own sheet.

The grades on file

Four Chemraz sheets are retained here, and the table is our reading of them, hardest grade first, with each grade's purpose in our words. The maker publishes these as typical properties measured on a -214 O-ring and says they are not specification limits. Where the maker names a grade we hold no sheet for, the page says so rather than borrowing a figure from a distributor table.

Chemraz 505 is rated by its maker from -30 C to 230 C, which is the coldest starting point of the four, and the maker calls it its universal grade. Chemraz 615 is rated from -18 C to 324 C and is the one to name for dry heat. Chemraz 605 is rated from -20 C to 260 C and is the maker's answer for hot amines and steam. Chemraz 526 is rated from -20 C to 250 C at 97 Shore A, and its brochure carries the decompression test record.

The rapid gas decompression record on 526

Rapid gas decompression, also called explosive decompression, blisters and cracks an elastomer when gas that soaked in under pressure expands faster than it can escape. Greene Tweed's brochure for Chemraz 526 reports that the grade passed the ISO 23936-2 and NORSOK M-710 test protocols and scored the top rating in the ISO decompression test, with the test conditions and damage scale printed on the sheet. The claim is the maker's, made on the maker's samples; a certificate for your lot comes from the maker with the part. Chemraz 526 is the grade the maker tested to NORSOK M-710.

Grades the maker names that we hold no sheet for

Greene Tweed also lists Chemraz 584 and 585, cream-colored grades for strong oxidizers and hot aqueous service, and 514 and 517, white grades made without carbon black for contamination-sensitive equipment. Distributor tables carry figures for them, but no maker sheet for those grades is retained here, so this page states none. Name the grade on the request and we quote it with the maker's sheet.

Chemraz and Kalrez on the same print

Prints often name both, or name one with "or equal". The two lines split into the same families, and a general grade from one maker is usually compared with the general grade from the other, but the figures on the sheets differ and the decision is your engineering's. The brands and grades cross-reference puts the maker figures side by side; the Kalrez page covers that line. Conquest quotes the part you approve and does not decide equivalence for you.

Sizes and forms we supply

All 369 AS568 sizes (349 general-purpose dash sizes plus the 20 boss-seal sizes) and the ISO 3601 metric series, in the durometers listed above. The AS568 chart and the metric chart carry the dimensions, and the dash number guide explains the numbering.

Sources: Chemraz 505 Universal Compound product brochure EN-DS069, Greene Tweed, 2018, read 2026-09-14; Chemraz 615 product brochure EN-DS081, Greene Tweed, 2018, read 2026-09-14; Chemraz 605 product brochure EN-DS080, Greene Tweed, 2018, read 2026-09-14; Chemraz 526 product brochure EN-DS011, Greene Tweed, 2018, read 2026-09-14; Parker O-Ring Handbook ORD 5700, section 2.2.10 (read 2026-09-14).

Parker is a trademark of Parker Hannifin Corporation. Chemraz is a trademark of Greene Tweed; Kalrez is a trademark of Qnity Electronics. No affiliation or endorsement is implied.

Reviewed by Grant Midstokke, Conquest Seal Corporation. Last updated September 2026. Material ranges are the published references named beside them; the compound datasheet and your application govern the final choice.