This specification covers the Positive Materials Identification (PMI) program for alloys and methods implemented by Purchaser to verify that the elemental composition of alloy materials is as specified in the purchase documents, and that materials are marked and stamped to indicate the proper alloy. The purpose of spectrum testing is to ensure that materials meet the quality requirements of pipe. The testing procedures to regulate the spectrum, especially the development of the regulations
2.1 This procedure is responsible for preparing the quality control department, technical department, or quality control review of Ministers, Deputy General Manager for approval.
2.2 This procedure is implemented by the quality control section
2.3 Quality control personnel to monitor the implementation of this regulation.
3. Preconditions before the start of this operation, the operating personnel should per-check the following prerequisites must be satisfied.
a. Operational areas should be clean and tidy, no other debris, the implementation of the procedures required for the surface smooth.
b. Operators shall be subject to technical and quality training, understand the relevant technical specifications, standards, and performance of the equipment used in this position, do understand the principle, to operate, simple maintenance.
c. To use the testing equipment should be in good condition, a qualified identification.
d The order shall be subject to review, approval.
a.excitation light source: The most commonly used metals arc light source, of silicon and other elements more difficult to stimulate the use of spark source.
b, electrode distance: Analysis of the distance between the sample and the excitation electrode is generally around 2mm to 3mm.
5. Identification of spectral lines: spectrum of different wavelengths has different colors different from the color area of each line and have different brightness and different arrangement, carefully observe the spectrum, the spectrum can be found in some of the more obvious features group of characteristics. Remember these features line group, individual lines of search is more convenient. Spectroscopic analysis of iron spectrum is the most basic spectra, whether of iron or non-ferrous metals generally can not do without it. Spectrum identification of iron and familiar, is to see an important step in spectral analysis. It is to identify other elements of a special scale wavelengths. Beginners should not hesitate to spend time and focus to master and familiar with the iron spectrum as soon as possible. The human eye can see 400nm to 700nm wavelength of the visible spectrum between.
6. Spectral Analysis Problems. In the spectrum of metal materials, the surface of the samples contaminated with paint and oil should be dealt with a clean place. There are three ways:
First, avoid areas contaminated with oil,
the second is to look at multi-spectral excitation electrode on the mirror one of the places where oil contamination would be the third is polished with a file about the oil-contaminated areas to ensure that the spectrum Analysis of samples when the accurate and reliable. Because some paints and there is a higher oil content in the Mo element. Spectroscopy acid-treated samples, the application of electrode samples and more excited for a while, to be material in the alloy element analysis of stability after the evaluation, to the burning time to master, it samples for analysis of the accuracy of is very important. Because the material treated with acid elements in the surface of gold
7. Spectrum heat-treated metal material should be more excited for a samples. Such as turning off the location of the metal surface temperature change color, Dianqi Han cutting off the metal surface, no cut-off saw tooth surface temperature change color part samples, these areas should pay more attention in the spectrum in order to ensure the accuracy of the results.
In the analysis of the same element, the electrode should be noted that clean, high content of alloying elements in the analysis of low content of alloying elements and then the electrode should be transferred to a clean area to prevent high levels of components into the low content of chemical elements Material analysis results, to ensure the accuracy of the results.
In dealing with the electrode is best polished with a file, such as sanding the electrode, the result of sand paper containing Si element, will pollute the electrodes, if not of Si element was no defense, such as analysis of Si element should pay attention to the best use of FILE polished electrode.
8. After sampling products for the corresponding inspection records, and sign the check list effective.
9. Department of quality control inspection records and reports and bound, safe custody, retention period of 7 years.
1. vendor shall comply with DOW specification.
“positive material identification program for project condor –PMI_55918Rev.1
“positive material identification program for project condor –PMI_55918Rev.1Addendum for equipment to be used in chlorine service”
“positive material identification –Doc No:G8S-4001-61”
2. Positive material identification shall be accomplished nondestructively using a radiation alloy analyzer(either an X-ray fluorescence analyzer or a spark emission spectrometer)when this instrumentation is available .Aspark emission spectrometer is to be used when is required to determine the carbon content of an alloy.
3. suppliers or fabricators shall have MTR available while performing PMI and attach to PMI Report .
4. In all cases ,the vendor or subcontractor shall be responsible to notify the purchaser for witnessing PMI. The purchaser may elect to witness some or all PMI.
The supplier or fabricator shall notify the purchaser is inspector at least five (5)working days in advance of any PMI testing.
5. The supplier or fabricator is responsible for color coding and stamping as required in this specification.
6. All pressure containing alloy parts shall undergo 100%PMI of each component.
7. Each alloy component which has been tested and accepted shall be identified by the supplier or fabricator with the code letters” PMI”at least 1/4-inch high using a low stress steel stamp.
Results of all PMI examinations shall be reviewed and signed by the Inspector on the positive material identification inspection report(see exhibit “B”) the report shall indicate as a minimum for each lot examined :
-supplier is and fabricator is names (supplier only when PMI inspected at source of supply).
-mill test certificate number and heat number .
-Inspection lot size and number of pieces or items examined.
-Number of pieces rejected and reason for rejection ,corrective actions.
-PMI analytic results in weight percentage.
-Description of marking.
-Method of examination (laboratory or analytic instrument).
9．PMI test by edge murry is members.
10.titanium hate rial shall be verified “cr,pd,zk”contents.