ASTM A995-2019 pdf free download
ASTM A995-2019 pdf free download.Standard Specification for Castings, Austenitic-Ferritic (Duplex) Stainless Steel, for Pressure-Containing Parts
1. Scope
1.1 This speci fication covers austenitic-ferritic (duplex) stainless steel castings for valves, flanges, fittings, and other pressure-containing parts. 1.2 The duplex stainless steels offer a combination of enhanced mechanical properties and corrosion resistance when properly balanced in composition and properly heat treated. Ferrite levels are not specified, but these grades will develop a range of approximately 30 to 60 % ferrite with the balance austenite. It is the responsibility of the purchaser to determine which grade shall be furnished depending on design and service conditions, mechanical properties, and corrosion- resistant characteristics. N OTE 1—Because of the possibility of precipitation of embrittling phases, the grades included in this specification are not recommended for service at temperatures above 600 °F [315 °C]. 1.3 The values stated in either SI units or inch-pound units are to be regarded separately as standard. The values stated in each system may not be exact equivalents; therefore, each system shall be used independently of the other. Combining values from the two systems may result in nonconformance with the standard. 1.4 This international standard was developed in accor- dance with internationally recognized principles on standard- ization established in the Decision on Principles for the Development of International Standards, Guides and Recom- mendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.
3. Terminology
3.1 Definitions of Terms Specific to This Standard: 3.1.1 duplex stainless steel— an iron-chromium-nickel- molybdenum alloy that, when properly heat treated, consists of approximately 30 to 60 % ferrite with the balance austenite.
4. General Conditions for Delivery
4.1 Material furnished to this specification shall conform to the applicable requirements of Specification A703/A703M, including the supplementary requirements that are indicated on the purchaser order. Failure to comply with the general requirements of Specification A703/A703M constitutes non- conformance with this specification. In case of conflict be- tween the requirements of this specification and Specification A703/A703M, this specification shall prevail.
S52.1 Casting Thickness, T—The casting thickness, T, is the maximum thickness of the pressure-containing wall of the casting exclusive of padding added for directional solidification, flanges, appendages, and sections designated by the designer as noncritical. The order, inquiry, and drawing shall designate what the test dimension, T, is for the casting. The test temperature shall be provided by the purchaser. If the test temperature is not specified, the test temperature used shall be –51 °F [–46 °C]. The average value of the three specimens shall not be less than specified in Table S52.1, with no more than one value permitted below the average minimum specified and no value permitted below the minimum specified for a single specimen. S52.2.3 When the thickness of the test block is greater than 4 in. [100 mm], test temperature and absorbed energy values shall be agreed upon between the purchaser and the manufac- turer. S52.3 Corrosion Testing—A Test Methods G48 Method A ferric chloride pitting resistance test shall be performed for a duration of 24 h at 60 °C. S52.3.1 The thickness of the test blocks used to create corrosion test specimens shall be equal to the casting thickness, T. Corrosion test specimens shall be removed from a location at one-quarter the thickness of the test block. S52.3.2 When the thickness of the test block is less than or equal to 4 in. [100 mm], test specimens shall show no evidence of pitting when examined optically at 20× magnification, and have a weight loss of <4g/m . S52.3.3 When the thickness of the test block is greater than 4 in. [100 mm], test block size and acceptance criteria shall be agreed upon between the purchaser and the manufacturer.
