This study is a key reason why GMP became popular as an accelerated laboratory corrosion test for steel. In recent years GMP has been replaced by. of the reference specimens in the as-received condition are in Figure 3. The salt fog test used an abbreviated procedure (Table 3) of the standard GMP test. Find the most up-to-date version of GMP at Engineering
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The quantity of spray applied should be sufficient to rinse away any salt accumulation left from previous sprays. Refer to Table 2 95440p targeted mass loss values, in milligrams, for various test durations as a function of the coupon’s original thickness.
Though believed to be accurate at the time of 940p, this may change over time. Also, the reasons why the targeted value s was not obtained should be investigated and corrected before resuming the test. Test Conditions The test consists of alternating wet and dry cycles with precisely prepared salt solution.
A siphon spray powered by oil-free regulated air or a hand operated pump spray may also be 9504p. Garden dusters from the following manufacturers could be modified: Test acceleration can be optimized and tracked by using standard corrosion coupons as monitoring devices. This method does not propose to address all the safety problems associated with its use. Additional options can be customized to specific components or subsystems to increase the ability to conduct validation or development testing.
At the end of test the samples shall be rinsed with fresh tap water mg allowed to dry before evaluating.
This study is a key reason why GMP became popular as an accelerated laboratory corrosion test for steel. Garden dusters with 954p0 8 mm diameter hole for dust application are recommended to achieve the appropriate level of dust application. The ambient shift can be modified to include additional test inputs such as dust, grit sprays, mechanical cycling, electrical cycling, thermal inputs, grayelometer and acid rain spray.
Test specimens in the enclosed chamber are exposed to a changing climate that generally comprises of the following 3 part repeating cycle variations to this cycle are permitted depending on the type of component under test — refer to the full test standard for further guidance. In recent years GMP has been replaced by its successor; GMW, but this is all but identical in terms of the test conditions required.
The latest revisions include: Figure 1 shows a completed coupon rack configuration. The solution shall be sprayed as a mist for example, from a plastic bottle onto the test samples and 95540p. Hudson Sprayer, Hudson Mfg. Wipe the coupons free mg grit and weigh to 954p0 the coupon mass loss using the formula: To analyze coupons remove 1 coupon from each end of the rack and prepare for weighing and mass loss determination. However, thicker coupon sizes should be used for tests with long durations.
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Typical test duration is 4 cycles for under dash mid to high mount locations and 12 cycles for floorpan low mount locations which approximately equals 10 yearscosmetic corrosion exposure.
Test samples shall be representative of production intent. The test is generally made up of 3 shifts: These methods should be used when reporting test results unless stated otherwise on drawings or agreed upon by test requestor and testor. Expected test duration fm evaluate functional corrosion is 10 phases. Any option changes not called out specifically in this Appendix must be included on the engineering drawing.
The weight, in milligrams mgshall be recorded and retained for future reference.
The spray nozzle shall be such that the salt solution is atomized into a mist as required. This method also includes measurement of corrosion creepback from a scribe line, and describes how to evaluate corrosion formation in unscribed areas. If possible, mount test specimens in a production representative orientation simulating onvehicle inputs e. This is considered an out of date browser. Use Option IV – for door detents without weatherseal protection Use Option VI – for door detents with weatherseal protection 1 test cycle is equal to 24 h, 1 phase is equal to 8 cycles.
Contact Ascott for Further Information. Typically no modifications of this shift. Ambient Soak 8 h. Engineering drawings and material specifications that reference this test procedure must specify the test duration, A, B, C or D or the number of test cycles as indicated in Table 1.
The number of coupons required for different test durations are shown in Table 1. The test procedure provides a combination of cyclic conditions salt solution, various temperatures, humidity, and ambient environment to accelerate metallic corrosion.
This standard was written by a task group and approved by the Letter Ballot Committee in February Ramp time is to be included as part of the specified exposure period. This process can be aided by using a commercial grade degreaser prior to methanol or acetone clean.
This procedure supersedes any old procedures that may have referenced an “A” or “B” Test Method Method A is eliminated. The number of cycle repeats and therefore the test duration is variable.
GMP | Standards | Ascott Analytical
This procedure describes an accelerated laboratory corrosion test method to evaluate assemblies and components. See Table 4 for the steps that comprise the test method.
Also, synergistic effects due to temperature, mechanical and electrical cycling can be comprehended by this test.