Petrochemical and refining
Petrochemical and refining
The failure mode
A joint that holds fine at ambient can lose its bolt load once the line is at 480 °C — the stud creeps, the gasket relaxes, and the flange starts weeping at the next thermal cycle.
What we supply
A193 B16 with its vanadium addition holds bolt load to 538 °C where B7 would relax. Paired with grade 4 or grade 7 nuts, not 2H.
Grades used here
B16-29 … 538 °C
ASTM A193 Grade B16
Chromium-molybdenum-vanadium alloy steel
860MPa min
B7-48 … 427 °C
ASTM A193 Grade B7
Chromium-molybdenum alloy steel (AISI 4140 / 4142 / 4145)
860MPa min
Gr 4-101 … 538 °C
ASTM A194 Grade 4
Carbon-molybdenum steel
—MPa min
Gr 7-101 … 538 °C
ASTM A194 Grade 7
Chromium-molybdenum alloy steel (AISI 4140)
—MPa min
Recommended coatings
Need a quotation?
Send us the grade, size and quantity. We reply within one working day with price, lead time and the certificate package included.