SAE AMS 4025N:2020 pdf free

SAE AMS 4025N:2020 pdf free.(R) Gas Nitriding of Low-Alloy Steel Parts
Pickled, plated, etched (to remove white layer), or electrolytically cleaned or stripped parts shall be baked to remove hydrogen as specified in AMS2759/9. Where pickling or electrolytic cleaning is performed as an integral part of a plating operation, baking is not required after each process but shall be performed following the final process provided not more than 4 hours elapse between such operations.
The depth shall meet the requirements of the engineering drawing. If the engineering drawing and/or purchase order specifies a case depth but does not specifically state that it is to be an effective case depth, total case depth, as defined below, shall apply. In cases where the engineering drawing or purchase order specifies post nitride surface removal (see ordering information), the reported case depth shall include the amount to be removed.
The total case depth shall be the depth of the continuous etching subsurface zone, determined metallographically from a section of the as-nitrided part or a control specimen prior to machining, or may be determined by a microindentation hardness traverse conducted in accordance with ASTM E384. On those alloys which do not respond by darker etching, the total case depth shall be the depth below the surface at which the hardness is 50 HK or 50 HV higher than the core below the nitride case, as determined by a Knoop or a Vickers hardness traverse respectively. The average of a minimum of three hardness readings taken at a minimum distance of 2X the case depth shall be used to determine the core hardness below the case.
Surface hardness shall be as specified in Table 2, determined in accordance with ASTM E18, or ASTM E384 after any material is to be removed. In case of dispute, the surface Rockwell superficial hardness shall govern provided the depth and hardness is appropriate to support the hardness value. If not, then the microindentation hardness at a depth of 0.002 inch (51 μm) from the surface shall take precedence. If material is to be removed as specified in the ordering information, the microindentation hardness values shall be taken at 0.002 inch (51 μm) from the predicted finished surface.SAE AMS 4025N pdf free download.