*Offer valid 12/26/16-12/30/16 while supplies last at participating Hallmark Gold Crown stores in the U.S.A. and at Hallmark.com. Discount will be taken on equal or lesser-valued item. Not valid on past purchases. Hallmark.com orders require U.S. billing and shipping addresses.
Depending on the application and the designof the seal, the material used may be nitrile, polyacrylate, fluoroelastomer(Viton), silicone, nylon or TeflonÂ¨. Nitrile is one of theleast expensive materials, and has been used for many years inumbrella or deflector type seals for older pushrod engines.
For very high temperature applications (say, over 200 Â°C.), general practice is to eliminate usage of any type of elastomers in seals; in such cases, all-metal seals are used in the form of metallic bellows. Other Body Material: The commonest material for seal body parts is Stainless Steels (Grades 304 or 316). Cheaper than these are sundry metals like brasses/bronzes/cast-irons/steels/etc. Springs, Grub Screws, Drive Pins, Drive Screws, etc., are all in St.Steels.