Low-Temp Flanges (ASTM A350)

A350 – This specification covers several grades of carbon and low alloy steel forged or ring-rolled flanges (LF2 in low-temp applications). 

Chemical Composition

Element Grade LF1 Grade LF2 Grade LF3 Grade LF5 Grade LF6 Grade LF9 Grade LF787
Carbon, max 0.30 0.30 0.20 0.30 0.22 0.20 0.07
Manganese 0.60-1.35 0.60-1.36 0.90 max 0.60-1.35 1.15-1.50 0.40-1.06 0.40-0.70
Phosphorus, max 0.035 0.035 0.035 0.035 0.025 0.035 0.025
Sulfur, max 0.040 0.040 0.040 0.040 0.025 0.040 0.025
SiliconA 0.15-0.30 0.15-0.30 0.20-0.35 0.20-0.35 0.15-0.30 …. 0.40-max
Nickel 0.40 maxB 0.40 maxB 3.3-3.7 1.0-2.0 0.40 maxB 1.60-2.24 0.70-1.00
Chromium 0.30 maxb,c 0.30 maxb,c 0.30 maxc 0.30 maxc 0.30 maxb,c 0.30 maxc 0.60-0.90
Molybdenum 0.12 maxb,c 0.12 maxb,c 0.30 maxc 0.12 maxc 0.12 maxb,c 0.12 maxc 0.15-0.25
Copper 0.40 maxB 0.40 maxB 0.40 max 0.40 max 0.40 maxB 0.75-1.25 1.00-1.30
Columbium 0.02 maxD 0.02 maxD 0.02 max 0.02 max 0.02 max 0.02 max 0.02 min
Vanadium 0.08 max 0.08 max 0.03 max 0.03 max 0.04-0.11 0.03 max 0.03 max
Nitrogen …. …. …. …. 0.01-0.030 …. ….