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 In recent years GMP has been replaced by.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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A cycle normally requires 1 day to complete. Contact Ascott for Further Information. This method does not propose to address all the safety problems associated with its use.
GMP | Standards | Ascott Analytical
The bolt, nut and washers shall be fm from a non black plastic material, preferably nylon. A cycle is made up of the daily events or test inputs prescribed in Table 4. The dryoff environment area shall be maintained with sufficient air circulation to prevent temperature stratification, and also allow thorough drying of the material.
This procedure describes an accelerated laboratory corrosion test method to evaluate assemblies and components. Typically, the time from ambient to the wet condition should be approximately 1 h and the transition time between wet and dry conditions should be approximately 3 h. Typical Application Originally developed by General Motors the standard has gained popularity for corrosion tests within the automotive industry and has also become the preferred corrosion test of the US Navy.
The test consists of alternating wet and dry cycles with precisely prepared salt solution. 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.
Prior to start of test, prepare the coupon rack with sufficient coupons to monitor the test 4. Test durations C and D or any modified test are to be used for validation and development purposes.
Ambient Soak 8 h. Test samples shall be representative of production ym. The solution shall be sprayed as a mist for example, from a plastic bottle onto the test samples and coupons.
Additional options can be customized to specific components or subsystems to increase the ability to conduct validation or development testing. If a recorder is not in use, written documentation should be provided indicating typical steady state conditions and the ramp times between steady states conditions. Hm requires a 16 h work day or an automatic cycling test chamber.
The test duration is dictated by the number of test cycles. Coupons consist of This method may involve hazardous materials, operations and equipment. If all solid materials are added dryan insoluble precipitate may result 3.
9504p Sprayer, Hudson Mfg.
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If specimen scribing is required, on either test panels or parts, follow the hm described in GMP. The test procedure provides a combination of cyclic conditions salt solution, various temperatures, 9540l, and ambient environment to accelerate metallic corrosion.
Modifications to the test may or may not attain equivalent levels of mass loss. Test durations A and B can be used for quality control and validation procedures as appropriate.
This procedure supersedes any old procedures that may have referenced an “A” or “B” Test Method Method A is eliminated. Both are excellent browsers.
GM P Cyclic Accelerated Corrosion Analysis of Nonchromate Conversion – Google Books
This is considered an out of date browser. These methods should be used when reporting test results unless stated otherwise on drawings or agreed upon by test requestor and testor. A phase is made up of a predetermined number of cycles, 8 cycles constitute 1 phase. Expected test duration to evaluate functional corrosion is 10 phases.
The coupon mass loss values shown in Table 2 are used to verify that the correct amount of corrosion has been produced 9540l the test. 9540l this information should not be used as a substitute for referring to a complete test standard, at an appropriate revision level.
Though believed to be accurate at the time of writing, this may change over time. Corrosion coupons shall be removed and analyzed after each phase throughout the test to monitor the corrosion. Humidity ramp times between the ym and wet condition and between the wet and dry conditions are critical to test acceleration this is because corrosion rates are highest during this transition period.
The weight, in milligrams mgshall be recorded and retained for future reference. This process can be aided by using a commercial grade degreaser prior to methanol or acetone clean. If a test is conducted with ramp times different than described above, the number of cycles to reach coupon mass loss targets may increase or decrease. See Table 4 for the steps that comprise the test method.
Test Conditions The test consists of alternating wet and dry cycles with precisely prepared salt solution. The humidity cabinet shall be as specified by GMP and Table 3. The test sample s shall be inspected for corrosion and photographed at the end of predetermined cycles.
Any option changes not called out specifically in this Appendix must be included on the engineering drawing. The test can be started at any time with the understanding that 24 h constitutes 1 cycle. Garden dusters with an 8 mm diameter hole for dust application are recommended to achieve the appropriate level of dust application.
However, thicker coupon sizes should be used for tests with long durations. Four 4 coupon thicknesses are available as shown in Table 2. You need to upgrade your browser You are using Internet Explorer 8 This is considered an out of date browser.
If possible, mount test specimens in a production representative orientation simulating onvehicle inputs e. At the option of the test requester, the test can be continued throughout weekends to decrease the over all test time.