Flanges Made from ASTM A537 Class1 Plates

Standards & flange types

Standards	Types
ASME B16.5	Blind Flange, Reducing Flange without hub, S/O Plate
ASME B16.47	Blind Flange, Reducing Flange without hub, S/O Plate
ASME B16.48	Figure-8 blank, Paddle blank, Paddle Spacer

*Flange types available made from ASTM A537 Cl.1 plates.

A series of pipe flanges can be manufactured from ASTM A537 Class 1 plates covering blind flanges, line blanks, slip-on plate flanges, and reducing flanges without hub. The ASTM A537 Class 1 plates refer to normalized C-Mn-Si steel pressure vessel plates intended for fusion welded pressure vessels and structures. The flanges may be manufactured in accordance with ASME B16.5, ASME B16.47, or ASME B16.48.

Pressure-Temperature ratings

ASTM A537 Class 1 steel is listed in material group 1.1 and it has the same pressure-temperature ratings as that of ASTM A350 Gr. LF2 and ASTM A516 Gr.70, etc.

Temp. °C	Working Pressures by Classes, bar
	75#	150#	300#	400#
−29~38	9.8	19.6	51.1	68.1
50	9.6	19.2	50.1	66.8
100	8.8	17.7	46.6	62.1
150	7.9	15.8	45.1	60.1
200	6.9	13.8	43.8	58.4
250	6.0	12.1	41.9	55.9
300	5.1	10.2	39.8	53.1
325	4.6	9.3	38.7	51.6
350	3.1	8.4	37.6	50.1
375	-	7.4	36.4	48.5
400	-	6.5	34.7	46.3
425	-	5.5	28.8	38.4
450	-	4.6	23.0	30.7
475	-	3.7	17.4	23.2
500	-	2.8	11.8	15.7
538	-	1.4	5.9	7.9

*Table 1-1: Pressure-temperature ratings for flanges made from ASTM A537 Class 1, Class 75 ~ Class 400, in metric units.

Temp. °C	Working Pressures by Classes, bar
	600#	900#	1500#	2500#
-29~38	102.1	153.2	255.3	425.5
50	100.2	150.4	250.6	417.7
100	93.2	139.8	233.0	388.3
150	90.2	135.2	225.4	375.6
200	87.6	131.4	219.0	365.0
250	83.9	125.8	209.7	349.5
300	79.6	119.5	199.1	331.8
325	77.4	116.1	193.6	322.6
350	75.1	112.7	187.8	313.0
375	72.7	109.1	181.8	303.1
400	69.4	104.2	173.6	289.3
425	57.5	86.3	143.8	239.7
450	46.0	69.0	115.0	191.7
475	34.9	52.3	87.2	145.3
500	23.5	35.3	58.8	97.9
538	11.8	17.7	29.5	49.2

*Table 1-2: Pressure-temperature ratings for flanges made from ASTM A537 Class 1, Class 600 ~ Class 2500, in metric units.

Temp. °F	Working Pressures by Classes, psi
	75#	150#	300#	400#
-20~100	140	285	740	985
200	130	260	680	905
300	115	230	655	870
400	100	200	635	845
500	85	170	605	805
600	70	140	570	755
650	60	125	550	730
700	-	110	530	710
750	-	95	505	675
800	-	80	410	550
850	-	65	320	425
900	-	50	230	305
950	-	35	135	185
1000	-	20	85	115

*Table 2-1: Pressure-temperature ratings for flanges made from ASTM A537 Class 1, Class 75 ~ Class 400, in US customary units.

Temp. °F	Working Pressures by Classes, psi
	600#	900#	1500#	2500#
-20~100	1480	2220	3705	6170
200	1360	2035	3395	5655
300	1310	1965	3270	5450
400	1265	1900	3170	5280
500	1205	1810	3015	5025
600	1135	1705	2840	4730
650	1100	1650	2745	4575
700	1060	1590	2655	4425
750	1015	1520	2535	4230
800	825	1235	2055	3430
850	640	955	1595	2655
900	460	690	1150	1915
950	275	410	685	1145
1000	170	255	430	715

*Table 2-2: Pressure-temperature ratings for flanges made from ASTM A537 Class 1, Class 600 ~ Class 2500, in US customary units.

Chemical composition requirements

ASTM A537 Class 1
Element		Composition
C	max	0.24
Mn	*H.A. t≤1-1/2"	0.70-1.35
	*P.A. t≤1-1/2"	0.64-1.46
	*H.A. t>1-1/2"	1.00-1.60
	*P.A. t>1-1/2"	0.92-1.72
P	max	0.025
S	max	0.025
Si	*H.A.	0.15–0.50
	*P.A.	0.13–0.55
Cu	*H.A. max	0.35
	*P.A. max	0.38
Ni	*H.A. max	0.25
	*P.A. max	0.28
Cr	*H.A. max	0.25
	*P.A. max	0.29
Mo	*H.A. max	0.08
	*P.A. max	0.09

*H.A.: heat analysis; *P.A.: product analysis; *t: flange/ plate thickness.

Mechanical requirements

ASTM A537		Class 1
*T.S. ksi [MPa]	t≤2-1/2"	70-90 [485-620]
	2-1/2"＜t≤4"	65-85 [450-585]
	4"＜t≤6"	A
*Y.S. ksi [MPa]	t≤2-1/2"	≥50 [≥345]
	2-1/2"＜t≤4"	≥45 [≥310]
	4"＜t≤6"	A
*EL. 2" min. %	2"	-
	4"≤t＜2"	22
	t＞4"	A
*EL. 8" min. %	[200mm]	18

*Mechanical requirements for ASTM A537 Class 1 flanges are thickness-dependent.