Standard Carbon Steel Flanges (ASTM A105)

ASTM A105 is an ASTM specification dealing with forged carbon steel piping components. 


Chemical Composition

Element C Mn P S Si Copper Ni Cr Mo V
Composition, % 0.35 max 0.60-1.05 0.035 max 0.040 max 0.10-0.35 0.40 max (1) 0.40 max (1) 0.30 max (1-2) 0.12 max (1-2) 0.08 max


(1) The sum of copper, nickel, chromium, molybdenum and vanadium shall not exceed 1.00%.
(2) The sum of chromium and molybdenum shall not exceed 0.32%.
For each reduction of 0.01% below the specified carbon maximum (0.35%), an increase of 0.06% manganese above the specified maximum (1.05%) will be permitted up to a maximum of 1.35%.

Flange Manufacturing Considerations

Heat treatment is not mandatory requirement except:

  1. Flanges above Class 300
  2. Flanges of special design where the design pressure at the design temperature exceeds the rating of Class 300.
  3. Flanges of special design where the design pressure or design temperature are not known.
Heat treatment, when required shall be annealing, normalizing OR normalizing and tempering OR quenching and tempering in accordance with ASTM A961