GM 9540P PDF
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 In recent years GMP has been replaced by.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 latest revisions include: If possible, mount test specimens in a gj representative orientation simulating onvehicle inputs e. The coupons serve to monitor the average general bare steel corrosion produced by the test gk.
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. Modifications to the test may or may not attain equivalent levels of mass loss.
Test samples shall be representative of production intent. 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. The solution shall be sprayed as a mist for example, from a plastic bottle onto the test samples and coupons. 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 vm under test — refer to the full test standard for further guidance.
The ambient shift can be modified to include additional test inputs such as dust, grit sprays, mechanical cycling, electrical bm, thermal inputs, grayelometer and acid rain spray. If a recorder is not in use, written documentation should be provided indicating typical gn state conditions and the ramp times between steady states conditions.
Ambient Soak 8 h. This website has been developed with modern 9540pp in mind to allow it to display at its best in a wide variety of viewing situations – including mobile viewing. This study is a key reason why GMP became popular as an accelerated laboratory corrosion test for steel.
This procedure supersedes any old procedures that may have referenced an “A” or “B” Test Method Method A is eliminated. Wipe the coupons free of grit and weigh to determine the coupon mass loss using the formula: If specimen scribing is required, on either test panels or parts, follow the methods described in GMP.
If the actual mass loss does not coincide with the targeted values listed in Table 2 the test gj be repeated.
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Any option changes not called out specifically in this Appendix must be included on the engineering drawing. The test procedure provides a combination of cyclic conditions salt solution, various temperatures, humidity, and ambient environment to accelerate metallic corrosion.
Figure 1 shows a completed coupon rack configuration. The weight, in milligrams mgshall be recorded and retained for future reference. Refer to Table 2 for targeted mass loss values, in milligrams, for various test durations as a function of the coupon’s original thickness.
GMP | Standards | Ascott Analytical
The salt mist solution shall be as specified in Table 3. So this information should not be used as a substitute for referring to a complete test standard, at an appropriate revision level. 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.
This procedure describes an accelerated laboratory corrosion test method to evaluate assemblies and components. The number of cycle repeats and bm the test duration is variable. However, thicker coupon sizes should be used for tests with long durations. The mist application hm while the samples and coupons are in the ambient environment. Water fog or visible water droplets on parts – continuous after equilibrium is reached.
If all solid materials are added dryan insoluble precipitate may result 3. Also, synergistic effects due to temperature, mechanical and electrical cycling can be comprehended by this test.
GM P Cyclic Accelerated Corrosion Analysis of Nonchromate Conversion – Google Books
The test consists of alternating wet vm dry cycles with precisely prepared salt solution. Humidity ramp times between the ambient 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 dryoff environment area shall be maintained with sufficient air circulation to prevent temperature stratification, and also allow thorough drying of the material.
It is the responsibility of the user of this method to establish appropriate safety and ggm practices and determine the applicability of regulatory limitations prior to use. This method may involve hazardous materials, operations and equipment. Corrosion coupons shall be removed and analyzed after each phase throughout the test to monitor the corrosion.
The test is generally made up of 3 shifts: Hudson Sprayer, Hudson Mfg. 95440p
Expected test duration to evaluate 95440p corrosion is 10 phases. In this context they can be considered to be equivalent and interchangeable terms. The temperature and humidity conditions are shown in Table 3. Test Conditions The test consists of alternating wet and dry cycles with precisely prepared salt solution.
Coupon mass loss targets for every phase are not included in Table 2. The procedure is effective for evaluating a variety of corrosion mechanisms, such as general, galvanic, crevice, 99540p.