SAE Standards Works
AMS CE Elastomers Committee
AMS7338A - Rubber: Butyl (IIR Abbreviation), Phosphate Ester Resistant, 65 to 75 Hardness, For Seals in Hydraulic Systems, etc.
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Rubber: Butyl (IIR Abbreviation), Phosphate Ester Resistant, 65 to 75 Hardness, For Seals in Hydraulic Systems, etc.
This specification covers a butyl rubber in the form of molded rings, compression seals, o-ring cord, and molded-in-place gaskets for aeronautical and aerospace applications. As AMS3238 is no longer valid for O-rings. For O-rings, the requirements of AMS7338 shall be met wherever AMS3238 is specified.
1. AMS-7338 was issued in Feb-2013 and is the O-ring sister AMS-7xyz spec to butyl AMS-3238. 2. It was issued with the same requirement ranges and tests as AMS-3238 with the only exception that test specimen was changes. 3. AMS-3238 specified testing on platens 4. Per long standing CE policy, AMS-7338 specified testing on end item O-rings if possible, else AS568-214 O-ring 5. Parker butyl B318 was already qualified to, and meets all requirements for, AMS-3238 6. Parker is the only NADCAP supplier for this spec. 7. Parker stated B318 cannot meet tensile strength and elongation requirement in AMS-7338 when testing on AS568-214 O-rings since tensile on O-rings typically gives lower tensile values than dogbones punched from platens. 8. Hence, it is requested that the tensile strength requirement be lowered from 1500 psi min to 1100 psi min; the elongation requirement be lowered from 300% to 225%. 9. Parker data supporting this change request e mailed to all separately since cannot be uploaded in this NEW PROJECT REQUEST FORM 10. Parker butyl B318 can meet all other requirements except tensile 11. This issue is of great importance and urgency to RMS since Parker is no-bidding all RFI to AMS-7338 12. Contact Sudhir Bafna at 520-471-6088 with questions