MIL-STD-2197A(SH)
4.4.1.1.2 Machine assisted application procedure. Specimen for qualification of procedures where the plated layer is applied with the assistance of a rotating head shall be a bar or pipe of sufficient wall thickness about 5 inches long by 0.75 inch Outside Diameter (OD) minimum. When the applicable procedure is used to fill pits or grooves, a groove 0.0625 inch wide by 0.010 inch deep by 1 inch long shall be cut into the specimen. The length dimension of the groove shall be parallel to the axis of the bar or pipe and at mid length.
4.4.1.2 Plating of qualification specimens. Defects shall be repaired by plating, if necessary. Plating shall be performed to a thickness equivalent to the maximum plating thickness to which the procedure is to be qualified on one side of strip or OD of bar or tube in accordance with the procedure.
4.4.1.3 Inspection requirements. After plating, the specimens shall be inspected to the requirements of 4.8.1,
4.8.3, and 4.8.4 and tested for adhesion as follows. Specimens need not be inspected until after grinding, if it is
specified.
4.4.1.3.1 Manual application procedure. The center of the strip shall be bent around a radius equal to four times the thickness of the test strip with the plating on the outside of the bend. The bent surface when examined at up to 5x magnification shall be acceptable if no separation or flaking occurs between the base metal and plating or the layers of plating, or if the plating cannot be peeled back with a sharp edged tool.
4.4.1.3.2 Machine assisted application procedure. The specimen shall be ground 0.003 inch off the diameter using standard grinding practice for the plating material. The plating shall be acceptable if no flashing or separation of plating occurs between the base metal and the plating or layers of plating.
4.4.1.4 Valve seat and disc repair procedures. To qualify procedures for repair of steam cuts and other damages in valve seats, discs, and stems, the following procedures are required (see 5.5.2):
a. Specimen: Mock-up to simulate production material, configuration, and restriction. The surface to be plated shall contain two grooves, 180 degrees apart, of about 0.125 inch wide by 0.010 inch deep.
b. Plating: Fill in grooves and provide a top coat of about 0.006 inch thick. c. Grinding: Grind to remove about 0.002 inch of top coat plating.
d. Inspection: The ground surface shall meet the acceptance criteria as specified in 4.8.1.
e. Micrographic: The specimens shall be sectioned through and perpendicular to each examination grooved area. The polished and etched cross sections shall be examined at 50x magnification minimum. Linear or rounded defects shall not be acceptable. Evidence of porosity, lack of adhesion, or cohesion shall not be acceptable.
f. Hardness test: Micro-indentation hardness testing shall be accomplished three times on the top coat of each specimen. Micro-hardness measurements shall be taken per ASTM E384. Hardness conversions shall be per
ASTM E140. The average hardness shall be not less than 380 Hardness Vickers (HV).
4.4.2 Qualification criteria. Prior to performing contact electroplating, prospective operators shall be qualified to perform this function by successful completion of training in the specified knowledge areas (see 4.4.2.1) and written and practical examination (see 4.4.2.2).
4.4.2.1 Training. The prospective operator shall demonstrate a working knowledge of the following:
a. The technical aspects of brush electroplating
b. Job safety for hazardous chemicals and electrical work
c. The calculation of plating amperage, plating time, quantity of solution required, and surface area and ampere-hours
d. The meaning of the following terms: current density, activation, anode, cathode, adhesion, burned deposits, modules, porosity stripping, etch, water-break, matte finish, and volts and amperes
e. Set up and operation of a power supply
f. Preparation of metal surface for brush electroplating
g. Selection, preparation of, and post use care of the plating tools (anodes) and covers h. The attributes used to control plating thickness time and quality
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