ASTM A789 covers standard requirements for grades of nominal wall thickness, stainless steel tubes for services requiring general corrosion resistance, with particular emphasis on resistance to stress corrosion cracking. These steels are susceptible to embrittlement if used for prolonged periods at elevated temperatures. Heat and product analyses shall be performed wherein the steel shall conform to the required chemical composition for carbon, manganese, phosphorus, sulfur, silicon, nickel, chromium, molybdenum, nitrogen, copper, and others. All stainless steel tubes shall be furnished in the heat-treated condition in accordance with the specified temperature and quenching conditions.
When the final heat treatment is in a continuous furnace, or when heat treated condition is obtained directly by quenching after hot forming, the number of stainless steel tubes of the same size and from the same heat in a lot shall be determined from the prescribed sizes of the stainless steel tubes. The material shall conform to the prescribed tensile and hardness properties. Mechanical tests such as tension tensile strength test, flaring test for seamless stainless steel tubes, stainless steel flanges test for welded stainless steel tubes, hardness test, and reverse flattening test shall be performed on the stainless steel tubes. Each tube shall also be subjected to the nondestructive electric test or the hydrostatic test.
This covers grades of nominal wall thickness, stainless steel tubes for services requiring general corrosion resistance, with particular emphasis on resistance to stress corrosion cracking. These steels are susceptible to embrittlement if used for prolonged periods at elevated temperatures.
The values stated in either inch-pound units or SI units are to be regarded separately as standard. The values stated in each system are not exact equivalents; therefore, each system must be used independently of the other. Combining values from the two systems may result in nonconformance with the specification. Within the text, the SI units are shown in brackets. The inch-pound units shall apply unless the M designation of this specification is specified in the order.
2. Referenced Documents
A1016/A1016M Specification for General Requirements for Ferritic Alloy Steel, Austenitic Alloy Steel, and Stainless Steel Tubes.
A480/A480M Specification for General Requirements for Flat-Rolled Stainless and Heat-Resisting Steel Plates, Sheets, and Bars.
E527 Practice for Numbering Metals and Alloys in the Unified Numbering System (UNS).
SAE J1086 Practice for Numbering Metals and Alloys (UNS).
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