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ASTM B277-95(2006)
Standard Test Method for Hardness of Electrical Contact Materials
2 стр.
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Разработчик:
Зарубежные/ASTM
ICS:
77.120.99 Other non-ferrous metals and their alloys / Цветные металлы и их сплавы прочие
Сборник (ASTM):
02.04 Nonferrous Metals – Nickel, Titanium, Lead, Tin, Zinc, Zirconium, Precious, Reactive, Refractory Metals and Alloys: Materials for Thermostats, Electrical Heating and Resistance Contact, and Connectors / Цветные металлы - Никель, Кобальт, Свинец, Олово, Цинк, Кадмий, Драгоценные металлы, химически активные металлы, Тугоплавкие металлы и сплавы, Материалы для Термостатов, Электронагревательных приборов, Контактов, Соединительные устройств
Тематика:
Other Nonferrous Metals
Описание
Значение и использование

The Rockwell hardness and Rockwell superficial tests are useful when the test specimens are sufficiently thick (in relation to the indentor load) to ensure that the results are not affected by the flow of metal on the surface of the anvil. On a solid piece the flow of metal on the under surface may be detected by a bulge or marking. On composite pieces where the contact materials are attached to backings of a different material, the thickness limitations imposed for a solid piece shall apply to the contact material portion of such composite pieces.

Note 1—As a matter of information, it may be stated that tests on fine silver showed that on annealed samples having a Rockwell 15T hardness of 27, the readings were not affected on thicknesses 1/16 in. (1.6 mm) or over. On thicknesses of 1/32 in. (0.8 mm) Rockwell 15T scale readings of 72 and higher were not affected.

The microhardness test is of questionable significance when the metallic phases in a material are so large that the indentation does not represent an accurate average hardness. Sintered contact materials usually contain segregates differing greatly in hardness from the matrix hardness and may destroy the validity of microhardness readings.

Other aspects of significance and use shall be as described in the particular ASTM test method used, as listed in Section 2.

Область применения

1.1 This test method covers the determination of the hardness of metallic materials used for electrical contacts. Rockwell, Rockwell superficial, Brinell, and microhardness tests are included, along with information on the limitations and use of these tests.

1.2 The values stated in inch-pound units are to be regarded as the standard. The SI units in parentheses are for information only.

1.3 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to become familiar with all hazards including those identified in the appropriate Material Safety Data Sheet (MSDS) for this product/material as provided by the manufactureer, to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.

Ключевые слова:
contacts; electrical contact materials; hardness; microhardness