Program on Data Sheet on Atmosperic Corrosion Properties for Low Alloy Steels

Corrosion or corrosion resistance of metallic materials is recognized as one of the most inportant factors to be considered in designing metallic structures such as steel brigdes and chemical plants with higher reliability. The flood of data has been accumulated by a lot of researchers' efforts up to now. However, corrosion of the materials is generally influenced by many metallugical , geometrical and environmental factors, and the diversity of these factors makes it in reality difficult to find appropriate corrosion data among the accumulated test data. Especially, the influence of environmental factors is extremely large for the atmospheric corrosion of metalls. Since these data are based on test results acquired independently in different laboratories for different purposes, a lack of consistency is sometimes inevitable. Systematic work to generate reliable atmosperic corrosion data seems to be necessary in order to comprehend properly the characteristics of atmosperic corrosion in materials and to become the research indicator of new anti-corrosion material development.

National Institute for Materials Science (NIMS) has executed the atmospheric corrosion research on metallic materials and organic coating so far. The planning of new exposure test program started in 1997 and the new facilities for atmospheric exposure examination were established at NIMS. This facilities are eqipped with 4 opened flames and 4 sheltered flames for exposure test, and one meteorological observation device refer to Figure 1-3). The NIMS atmosphere corrosion data sheet is aimed to clarify systematically the standard characteristics of atmospheric corrosion about various metallic materials used for the structures which atmospheric corrosion is important, and the basic alloy materials that becomes an indica-tor for new anti-corrosion material developments. For this purpose, test materials are sampled by NIMS from the current commercial products of representative manufactureres in this country, and exposure tests are going to be carried out at NIMS according to standard test procedures (see Table 1 for materials tested, and Table 2 for the test schedule).

Test alloys are made by representative manufactureres. The data sheets will serve as variable guide, not only for design engineers but also for investigators in the fields of corrosion science and engineering. In order to determine the most effective direction for this program, an advisory committee for data sheets was instituted at NIMS in 2001 in cooperation with leading specialists from related academic and industrial societies in Japan. To this is attached a technical advisory commit-tee, for the purpose of planning the program in the best way. The menbers for these comittees are given in Appen-dixA. On May 20, 2002, NIMS obtained ISO 9001 Certifica-tion for the Quality Management Systems for our Materi-als Data Sheet Project, and Creep test and Accident In-vestigation Services that are closely related to the project.

NIMS intends to continuously improve the reliability and quality of our research and related services while always using the ISO 9001 standard as a basic criterion. Listening to and responding to clients' requests are standard oper-ating procedures in our research and service programs.

Figure and Table

Fig.1 Outline of NIMS exposure test site.

Fig.2 Outline of open exposure test flame.

Fig.3 Outline of sheltered exposure test flame.

Table 1 Materials for atmospheric corrosion test
MaterialsObtaining routeShape
Electrolytec iron99.95%FemeltPlate
Fe-Ni binary alloyFe-1%NimeltPlate
Fe-Cr binary alloyFe-1%CrmeltPlate
Fe-Ni-Cr alloyFe-1%Ni-1%CrmeltPlate
Carbon steelSM490AmarketPlate
Weathering steelSMA490marketPlate
Fe-Si binary alloyFe-1%SimeltPlate
Fe-Al bianry alloyFe-1%AlmeltPlate
Fe-Si-Al alloyFe-1%Si-1%AlmeltPlate
Fe-Cu binary alloyFe-0.4%CumeltPlate
Fe-P binary alloyFe-0.5%PmeltPlate

Table 2 Schedule of sampling of test pieces and issue of corrosion data sheets