Wall thickness:1 mmmm 3. Length: 6 metre or as per customer request Duplex stainless steels are extremely corrosion resistant, work hardenable alloys. Their microstructures consist of a mixture of austenite and ferrite phases. As a result, duplex stainless steels display properties characteristic of both austenitic and ferritic stainless steels. This combination of properties can mean some compromise when compared with pure austenitic and pure ferritic grades.
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Where ellipses Product Analysis 1. An analysis of either one billet or one length of flat-rolled stock or one tube shall be made from each heat. The chemical composition thus determined shall conform to the requirements specified. The product analysis tolerance is not applicable to the carbon content for material with a specified maximum carbon of 0.
If the original test for product analysis fails, retests of two additional billets, lengths of flat-rolled stock, or tubes shall be made. Both retests for the elements in question shall meet the requirements of this specification; otherwise, all remaining material in the heat shall be rejected or, at the option of the producer, each billet or tube may be individually tested for acceptance.
Billets, lengths of flat-rolled stock, or tubes that do not meet the requirements of this specification shall be re- jected. NOTE 1—For flange and flaring requirements, the term lot applies to all tubes prior to cutting of the same nominal size and wall thickness that are produced from the same heat of steel. When final heat treatment is in a batch-type furnace, a lot shall include only those tubes of the same size and from the same heat that are heat treated in the same furnace charge.
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 tubes of the same size and from the same heat in a lot shall be determined from the size of the tubes as prescribed in Table 3. NOTE 2—For tension and hardness test requirements, the term lot applies to all tubes prior to cutting, of the same nominal diameter and wall thickness that are produced from the same heat of steel.
When final heat treatment is in a batch-type furnace, a lot shall include only those tubes of the same size and the same heat that are heat treated in the same furnace charge. When the final heat treatment is in a continuous furnace, or when heat treated condition is obtained directly by quenching after hot forming, a lot shall include all tubes of the same size and heat, heat treated in the same furnace at the same temperature, time at heat, and furnace speed, or all tubes of the same size and heat, hot formed and quenched in the same production run.
Mechanical Tests Required 1. Tension Tests—One tension test shall be made on a specimen for lots of not more than 50 tubes. Tension tests shall be made on specimens from two tubes for lots of more than 50 tubes see Note 2.
Flaring Test for Seamless Tubes —One test shall be made on specimens from one end of one tube from each lot see Note 1 of finished tubes.
Flange Test for Welded Tubes —One test shall be made on specimens from one end of one tube from each lot see Note1 of finished tubes. Hardness Test—Brinell or Rockwell hardness tests shall be made on specimens from two tubes from each lot see Note 2. When more than one heat is involved, the tension, flaring, flanging, and hardness test requirements shall apply to each heat.
Reverse Flattening Test—For welded tubes, one reverse flattening test shall be made on a specimen from each ft [ m] of finished tubing. Hydrostatic or Nondestructive Electric Test 1 Each tube shall be subjected to the nondestructive electric test or the hydrostatic test. The type of test to be used shall be at the option of the manufacturer, unless otherwise specified in the purchase order.
Stainless Steel and Duplex Pipe (ASTM A312, A790)
Stainless steel has been developed at the beginning of the century to cope with the increasing demand, across many industries, for more durable steels that could withstand demanding service conditions. Stainless steel was conceived as an evolution of standard carbon steel and obtained by adding alloying elements to the base iron like Nickel and Chromium. The addition of such alloying elements enhances the resistance of the steel to corrosion in harsh applications. Before digging into the different grades, lets review the types of stainless steels available on the market and their classification. However, a multitude of grades is available depending on the mix of the alloying elements Nickel.
More A The pipe shall be made by the seamless or an automatic welding process, with no addition of filler metal in the welding operation. Heat analysis shall be made to determine the percentages of the elements specified. Tension tests, hardening tests, flattening tests, hydrostatic tests and nondestructive electric tests shall be made to conform to the specified requirements.