GMNA - 9985734
Resin, Impregnation, Heat-Cured
|Publication Date:||1 April 2015|
This specification describes requirements and tests for a heat-cured plastic resin intended for the impregnation of porous metal castings and powdered metal components. See 7.1.
Symbols. Not applicable.
Application Limit. Intended as a single application to components that don't initially pass final leak test due to porosity in the metal.
Usage and Temperature Limits. After impregnation, under no circumstances should the continuous or excursion product temperatures of the material manufacturer be exceeded. This is a Class B product suitable for components operating in that continuous temperature range (Table 1, shaded). Discuss with the resin supplier the nature and frequency of the excursions before making a selection. See Table 1, Class B. Do not confuse this with storage shelf-life, 3.7.3.
Note 1: The temperature classifications are consistent with MIL-I-17563C.
Note 2: Excursion time at temperature is determined by the resin manufacturer. Consult with them regarding your specific application before selecting your product.
Process Use Limits.
The product is applied after all heat treatments and before or after machining.
This product is only intended to seal porosity and no other process defect.
Use of impregnation product is strictly a temporary measure to resolve a porosity condition. The condition limits under which use is allowed are defined in the Component Technical Specifications (CTS) or the Statement of Requirements (SOR) for the part or component. If no provisions are stated, no impregnation is permitted.
Precautions. Resin use is recommended only as a temporary preventative measure to fill porosity contributing to air or fluid leak(s) until a metal forming process solution to eliminate porosity leakage is satisfactorily completed. The long term durability of this impregnation product is not known because it is rarely used. GMW3155 Testing of Impregnated Parts is highly recommended to assist in defining long term sealing performance.
Expired Product. Authorized use of this product past its expiration shall be determined from compliance to tests in this standard performed at the resin supplier and reviewed and approved by responsible GM personnel. Only product properly stored (see 3.7.3) in unopened original containers shall be tested.
This material is introduced into a cleaned part by a vacuum and/or pressure process. It reaches a cured state with the addition of heat.
Air leakage of the part or component determines before and after if the impregnation process is suitable. Consult the SOR or CTS for the part or component.
Resin discoloration may occur after impregnation. This is normal and shall not be cause for rejection of the component.
Normally pressure penetration testing occurs on non-machined specimens (see 18.104.22.168), however since machined parts are impregnated, the testing requires machined and etched surfaces.