ASTM (American Society for Testing Materials)
Specifications These are basically materials specifications. ASTMA A-403 (Factory Made Wrought Austenitic Steel Welding Fittings) lists the permissible raw materials from which fittings can be made. In addition, it controls the method of manufacture, quality assurance and marking. The corresponding ASME Spec is SA-403. This is found in Section II Part A of the ASME Boiler and Pressure Vessel Code. This is similar, but not identical to ASTM A-403. ASME (American Society of Mechanical Engineers) Boilers and
Pressure Vellel Code and MSS (Manufacturers Standardization Society)
Standards Other supplementary ASME and MSS standards: ASME B 16.25 - Butt welding end preparations In response to the need of the process industries, SP-43 Specification was issued in 1950 by the Manufacturers Standardization Society. At that time, stainless steel piping was used for its resistance to corrosion and to eliminate product contamination. Pressure was seldom a factor. Pressure ratings for 5S and 10S fittings are shown in MSS SP-43. They reflect the emphasis on corrosion resistance rather than pressure. These pressure ratings are less than the allowable pressure ratings that are applicable to the matching pipe. Today there are many applications for schedules 5S and 10S piping at higher pressures than those permitted in SP-43. To cover this, SP-43 was revised to include a statement, "For fittings of same pressure rating of matchine pipe, refer to ASME-B 16.9." SP-43 and B 16.9 are similar dimensionally in that the fixed position for the welding ends with reference to the centerline of the fitting and the overall dimensions are identical. ASME B 16.9 has the added provision that the pressure of the fitting shall at least equal the computed bursting pressure of seamless pipe of the same wall thickness and material. In order to differentiate fittings made to these specifications, the prefix "CR" is shown before the alloy designated for SP-43 and the symbol "WP" is shown to indicate B 16.9 fittings. A user who wants to obtain 5S and 10S to B 16.9 fittings must reference this Spec when ordering fittings to ASTM A-403. If B 16.9 is not specified, the manufacturer may supply either SP-43 or B 16.9 at his option. |
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