FORM: AT-1927-98
Revision Date: 4/16/24

Page 1 of 2

One Allison Way
Indianapolis, Indiana
46222-3271 USAAMS-2481
Phosphate Treating Antichafing*DATE*QUANTITY TESTED*ORGANIZATION*PART NUMBER*PHOSPHATE SUPPLIER*PART NAME*NAME OF LABORATORY*BATCH TRACE NUMBER*TIER 1 Machiner*Tier 1 PO Number*SUPPLIER VENDOR CODE
AMS-2481 Phosphate Treating Specification
Phosphate Coating Supplier is to adhere to ALL sections noted on AMS2481
3.1.1.1.2 – Stress Relief for hardness HRC 40 and above
3.1.1.1 – Clean and remove surface contaminationSPECIFICATION/ LIMITS(min/max)
Review sections 1through 8.6
40-54 375 deg F +-25>55 275 deg F for
5-10 hours
Verify cleanlinessand perform water
break test

3.3.2 – Hydrogen Embrittlement – After phosphate coating treatment of steel
parts having a hardness of 40HRC or higher shall be in accordance with
AMS2759/9 except parts shall be baked at 210 to 225 degrees F for 8 hours

210-225 deg F at 8hours

3.4.3 Phosphate coating weight

1500mg/ft2 min

4.3.4 – Hydrogen Embrittlement Test shall be accordance with ASTM F519
Type 1a1 using round notched specimens, coating shall meet the requirementsof this specification on specimen surfaces and shall be visible at the root of thenotch.
4.3.1 Acceptance Tests
4.2.2 Periodic Tests – Coating weight is a periodic test and shall be performedat least monthly.
3.4.2 Verify appearance – Coated parts shall have a unform grayish black ,finley crystalline appearance
3.5 Quality appearance – Surfaces of treated parts shall be unfirom in texture
and appearance . Powdery areas, excessvie buildup and darkening of corners
and edges are not acceptable
3.3.1 After rinsing, parts shall be immersed in hot water. Parts shall bethoroughly dried unless a water displacing oil is used for protection of parts .
Dried parts shall be oiled with sutabile corrosion inhibiting oil
4.4.3 Control factors shall include
Immersion time
Surface preparation and cleaning procedures
Phosphating solution composition and composition control limits
Phosphating solution temperature limits and controls
Post treatment solution control limits and procedures
Hydrogen embrittlement relief bake time and temperature
Corrostion inhibiting oil
Stripping procedure if used
4.6.2 Non-Conforming Control Factors – If non-conforming parts arediscovered, no additional parts shall be made and process should be locked out.
4.5 Reports – Certification – The coating vendor shall furnish with each
shipment a report or certification stating that the parts have been processed andtested in accordance with the requirements of this specification and that coatedparts conform to the acceptance test requirements. This certification shall
include the PO, lot number, compliance to AMS2481K, part number andquantity. The supplier’s certifaction along with AT-1927-98 form must beprovided with every lot shipped.

Verify ASTM F519Must meet test
sampling chart
shown in Table 1
Perfom at least
monthly
Verify appearance
Verify appearance
Verify corrosion
protection and note
specific oil used
Verify section 4.4.3
was completed
including all control
factors listed

Follow “ReactionPlan” for nonconforming material
Provide Phosphatecertification on every
batch to section 4.5
along with this AT1927-98 form.

SUPPLIER TESTRESULTS (DATA)OKNOTOK