General Introduction to DIN Standard Flanges
1. General Introduction to DIN series flanges
Although DIN standard flanges now have been superseded by EN 1092-1, it is still commonly used in project practice. DIN series flanges cover an extensive range of pressure ratings from 1 bar(PN 1) to 400 bar(PN 400): 1 bar, 2.5 bar, 6 bar, 10 bar, 16 bar, 25 bar, 40 bar, 64 bar, 100 bar, 160 bar, 250 bar, 320 bar, 400 bar. According to SI unit system, 1 bar = 100 kPa = 0.1 MPa = 14.5 psi. Usually, DIN standard flanges are categorized as:
1) Weld neck flanges: DIN 2630(PN 1 & 2.5); DIN 2631(PN 6); DIN 2632(PN 10); DIN 2633(PN 16); DIN 2634(PN 25); DIN 2635(PN 40); DIN 2636(PN 64); DIN 2637(PN 100); DIN 2638(PN 160); DIN 2628(PN 250); DIN 2629(PN 320); DIN 2627(PN 400)
2) Lapped flanges plain collar(lapped joint): DIN 2641(PN 6); DIN 2642(PN 10)
3) Flat flanges for welding(Slip On): DIN 2573(PN 6); DIN 2576(PN 10); DIN 2502(PN 16); DIN 2503(PN 25 & 40)
4) Blind flanges: DIN 2527(PN 6, 10, 16, 25, 40, 64 & 100)
5) Loose flanges and rings for welding(slip on and plain colloar): DIN 2652(PN 6); DIN 2653(PN 10); DIN 2655(PN 25); DIN 2656(PN 40)
6) Loose flanges and ring with neck for welding: DIN 2673(PN 10)
7) Oval plain threaded flanges: DIN 2558(PN 6)
8) Oval flanges with neck threaded: DIN 2561(PN 10 & 16)
9) Long weld neck flanges: DIN 28115(PN 10 & 25)
10) Hubbed slip on flanges for welding: DIN 86029(PN 10); DIN 86030(PN 16)
11) Threaded flanges with neck: DIN 2565(PN 6); DIN 2566(PN 10 & 16); DIN 2567(PN 25 & 40); DIN 2568(PN 64); DIN 2569(PN 100)
2. Materials for DIN standard flanges
1) Carbon steel: St 37.2, S235JR, C 22.8(DIN 1.0460), DIN 1.0619(N)
2) Stainless Steel: SS 304(1.4301), SS 304L(1.4306), SS 316(1.4401), SS 316L(1.4404),
SS 321(1.4541), SS 347(1.4550), SS 410(1.4000), 254 SMO(1.4547),
Duplex SS(1.4462), Super Duplex SS(1.4410), SS 904(1.7440)
3) Alloy: Al 1050(3.0255), Copper(2.0090), Nickel 200(2.4066), Monel 400(2.4360),
Inconel 600(2.4816), Inconel 625(2.4856), Incoloy 800(1.4876), Incoloy 825,
Hastelloy B2(2.4617), Hastelloy C 276(2.4819), Titanium Gr.2(3.7025)
3. Dimensional tolerances for DIN flanges
1) Tolerance of outside diameter(O.D):
for O.D ≤ 200 mm, ±1.0 mm(faced) while ±2.0 mm(not faced).
for 200 mm < O.D ≤ 300 mm, ±1.5 mm(faced) while ±2.0 mm(not faced).
for 300 mm < O.D ≤ 400 mm, ±2.0 mm(faced) while ±3.0 mm(not faced).
for O.D > 400 mm, ±2.0 mm(faced) while ±5.0 mm(not faced).
2) Tolerance of inside bore diameter(I.D):
for I.D ≤ 100 mm, ±0.5 mm(other types) while -1.0 mm(weld neck types).
for 100 mm < I.D ≤ 400 mm, +1.0 mm(other types) while -1.5 mm(weld neck types).
for I.D > 400 mm, +1.5 mm(other types) while -2.0 mm(weld neck types).
3) Tolerance of flange thickness(t):
for t ≤ 10 mm, ±0.5 mm(both sides) while ±1.0 mm(one side).
for 10 mm < t ≤ 20 mm, ±0.8 mm(both sides) while ±1.3 mm(one side).
for 20 mm < t ≤ 30 mm, ±1.0 mm(both sides) while ±1.5 mm(one side).
for 30 mm < t ≤ 50 mm, ±1.0 mm(both sides) while ±1.5 mm(one side).
for W.T > 50 mm, ±1.5 mm(both sides) while ±2.0 mm(one side).
4) Tolerance of flange overall height(H):
for H ≤ 80 mm, ±0.5 mm.
for 80 mm< H ≤ 250 mm, ±2.0 mm.
for H > 250 mm, ±3.0 mm.
5) Tolerance of diameter of raised face(g):
for g ≤ 80 mm, -1.0 mm.
for 80 mm < g ≤ 300 mm, -2.0 mm.
for g > 300 mm, -3.0 mm.
See the contact face types, surface finish and bevel ends of DIN standard flanges.
