This specification covers the requirements and corresponding test methods for two iron-nickel alloys and one iron-nickel-cobalt alloy, for low thermal expansion applications. The two iron-nickel alloys, which both contain nominally 36 % nickel and 64 % iron, are the conventional alloy designated as UNS No. K93603 and the free-machining alloy designated as UNS No. K93050. On the other hand, the iron-nickel-cobalt alloy contains nominally 32 % nickel, 5 % cobalt and 63 % iron, and is designated as UNS No. K93500. UNS No. K93603 and UNS No. K93500 shall be in the forms of wire, rod, bar, strip, sheet plate, and tubing, while UNS No. K93050 shall be for bar products only. When test, the alloys shall comply to specified requirements for chemical composition, surface finish, temper, grain size, hardness, tensile strength, thermal expansion, transformation, and dimensions.
This abstract is a brief summary of the referenced standard. It is informational only and not an official part of the standard; the full text of the standard itself must be referred to for its use and application. ASTM does not give any warranty express or implied or make any representation that the contents of this abstract are accurate, complete or up to date.
1.1 This specification covers two iron-nickel alloys and one iron-nickel-cobalt alloy, for low thermal expansion applications. The two iron-nickel alloys, both containing nominally 36 % nickel and 64 % iron, with the conventional alloy designated by UNS No. K93603, and the free-machining alloy designated as UNS No. K93050. The iron-nickel-cobalt alloy, containing nominally 32 % nickel, 5 % cobalt and 63 % iron, is designated by UNS No. K93500. This specification defines the following product forms for UNS No. K93603 and UNS No. K93500: wire, rod, bar, strip, sheet plate, and tubing. The free-machining alloy, UNS No. K93050, is defined for bar products only. Unless otherwise indicated, all articles apply to all three alloys.
1.2 The values stated in inch-pound units are to be regarded as standard. The values given in parentheses are mathematical conversions to SI units that are provided for information only and are not considered standard.
1.3 This pertains only to the test method section, Section 13. 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 establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.
2. Referenced Documents (purchase separately) The documents listed below are referenced within the subject standard but are not provided as part of the standard.
D1971 Practices for Digestion of Water Samples for Determination of Metals by Flame Atomic Absorption, Graphite Furnace Atomic Absorption, Plasma Emission Spectroscopy, or Plasma Mass Spectrometry
E8 Test Methods for Tension Testing of Metallic Materials
E10 Test Method for Brinell Hardness of Metallic Materials
E18 Test Methods for Rockwell Hardness of Metallic Materials
E29 Practice for Using Significant Digits in Test Data to Determine Conformance with Specifications
E45 Test Methods for Determining the Inclusion Content of Steel
E92 Test Method for Vickers Hardness of Metallic Materials
E112 Test Methods for Determining Average Grain Size
E140 Hardness Conversion Tables for Metals Relationship Among Brinell Hardness, Vickers Hardness, Rockwell Hardness, Superficial Hardness, Knoop Hardness, and Scleroscope Hardness
E228 Test Method for Linear Thermal Expansion of Solid Materials With a Push-Rod Dilatometer
E354 Test Methods for Chemical Analysis of High-Temperature, Electrical, Magnetic, and Other Similar Iron, Nickel, and Cobalt Alloys
E1019 Test Methods for Determination of Carbon, Sulfur, Nitrogen, and Oxygen in Steel, Iron, Nickel, and Cobalt Alloys by Various Combustion and Fusion Techniques
E1601 Practice for Conducting an Interlaboratory Study to Evaluate the Performance of an Analytical Method
iron-nickel alloys; iron-nickel-cobalt alloys; low expansion alloys; precision instruments; UNS No. K93050; UNS No. K93500; UNS No. K93603; Electronic materials/applications--specifications; Iron-nickel alloy--specifications; Iron-nickel-cobalt alloys--specifications; Low expansion alloy; Low thermal expansion; UNS K93050 (Fe-Ni low expansion alloy, Invar FC); UNS K93500 (Fe-Ni-Co low expansion alloy, Super Invar); UNS K93603 (Fe-Ni low expansion alloy, Invar) ; ICS Number Code 3603; 77.100 (Ferroalloys); 77.120.40 (Nickel, chromium and their alloys)
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