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ANSI B16.47 SER.B Forged Flanges Finish &Tolerance and Material Specifications

ANSI B16.47 SER.B Forged Flanges Finish &Tolerance and Material Specifications

Finish &Tolerance and Material Specifications
Finish &Tolerance
ANSI B16.47 SER.B Forged Flanges

 1.Standard Finishes for Contact Face of Flanges
The flange face shall have a serrated finish consisting of 20 to 40 grooves per inch, 0.002 in. to 0.005 in. deep, cut spirally or concentrically with a round-nose tool.

2.Dimensional Tolerance for ASME B16.47 SER.B Flanges.
Outside diameter of raised face ±0.8mm
Flange thickness + 4.8mm, - 0mm
Length thru hub ±3.0mm
Diam. of hub at bevel + 4.1mm, - 0.8mm
Bolt circle diameter ±1.6mm
Center-to-center of adjacent bolt holes ±0.8mm
+ 3.0mm,- 1.6mm
Outside diameter ±3.0mm
Diameter at base of hub ±3.0mm

  1.   Flanges shall have bearing surfaces for bolting that are parallel to the flange face within I degree. Any back facing or spot facing required to accomplish parallelism between the flange face and nut bearing surface on the back of the flange shall not reduce the flange thickness.
  2.   Tolerance for the welding end of a welding neck flange shall be in conformance with ANSI B16.25.
  3.   Other tolerances than specified the table shall be in accordance with ANSI B16.5.
  4.   The flange shall be either back-faced or spot-faced at the bolt-holes on the flange back if the nut bearing surface at the back of the flange is not parallel with the flange face within the tolerances listed in Note, if the fllet at the hub interferes with the nut bearing surface or if the flange thickness exceed the minimum required thickness by more than 0.19 inch ( 4.8 millimeters ). 

Material Specifications
  1. The Steel used in the manufacture of these flanges shall be selected to meet the following requirements.
  2. The F48 and higher grades of Class 400, 600 and 900 flanges shall be killed steel.
  3. The steel used shall be suitable for field welding to other flanges fttings, or pipe manufactured under ASTM specifications A105, A53, A106, A381 or API Standards 5L and 5LX.
  4. The steel used shall have a maximum carbon content of 0.35 and a carbon equivalent computed by the following equation.

  that should not exceed 50%, based on check analysis, if the carbon equivalent factor exceeds 0.50%, the acceptance of the flanges shall be based on agreement of customer.

  1. The choice and used of alloying elements, combined with the elements within the limits prescribed in paragraph A. d. to give the required tensile properties prescribed in paragraph A. f. shall be made by AJF. and reported in the chemical analysis to identify the type of steel.
  2. The steel used shall have tensile properties conforming to the requirements prescribed in following table.
  The F42 and higher grades of flanges of all pressure classes and the class 400 and higher classes of Grade F36 flanges shall be normalized or quenched and tempered.

  The test specimens may be taken from the forgings or, at the manufactures option, from the billets or forging bar entering into the finished product, provided such test blank has undergone relatively the same forming and the equivalent heat treatment as the finished flange. The dimensions of the test blank must be such as to adequately reflect the heat treatment properties of the hub of the flange.