ASTM A182 Gr. F321 Flanges | ASME B16.5 & B16.47

Flanges manufactured in accordance with ASME B16.5 or ASME B16.47 may be made from ASTM A182 grade F321 forgings, which has the nominal composition of 18Cr-10Ni-Ti. ASTM A182 Gr. F321 is a titanium-stabilized austenitic stainless steel, in which titanium is added to avert sensitization to intergranular corrosion when the flange has prolonged exposure to the temperature between 425°C to 815°C [800°F to 1500°C]. The precipitation of chromium carbides at such a temperature results in chromium depletion at the very area adjacent to grain boundaries, which is the cause of intergranular corrosion. ASTM A182 Gr. F321 has a titanium content of not less than five times the carbon plus the nitrogen content and not more than 0.70%. Since titanium carbide is more stable, the carbon content prefers to react with titanium to form titanium carbides before combining with chromium. In such a way, depletion of chromium is eliminated. However, since nitrogen has higher affinity with titanium than carbon, titanium shall be furnished in sufficient amount to cover both the carbon and nitrogen.

Chemical Composition Requirements

Element	Composition, %
C	≤0.08
Mn	≤2.00
P	≤0.045
S	≤0.030
Si	≤1.00
Ni	9.0-12.0
Cr	17.0-19.0
Ti	*J

* Titanium content of ASTM A182 F321: 5×(C+N) ≤ J ≤ 0.70%.

Mechanical Properties & Heat Treatment

Tensile Test	Requirements
Tensile Strength min. MPa [ksi]	515 [75]
Yield Strength min. MPa [ksi]	205 [30]
Elongation in 2", min. %	30
Reduction of Area, min. %	50

*ASTM A182 Gr. F321 forged flanges shall be solution treated at a temperature between 1900~1950°F [1040~1065°C], and followed by a quench in water to rapidly cool it down below 500°F [260°C]. Subsequent to the solution anneal for Gr. F321 flanges, a stabilizing treatment at 1500°F to 1600°F [815°C to 870°C] for a minimum of 2 hours per inch of thickness and then cooling in the furnace or in air.

Pressure-Temperature Ratings

The pressure-temperature (P-T) ratings for ASTM A182 Gr. F321 flanges are presented in below tables, indicating maximum allowable working gauge pressures in psi units at the temperatures in degrees Fahrenheit. ASTM A182 F321 flanges made in accordance with ASME B16.5 are available in Class 150, 300, 400, 600, 900, 1500, and 2500. They are available in Class 150, 300, 400, 600, 900, and in Class 75, 150, 300, 400, 600, 900 for Series A and Series B flanges of ASME B16.47, respectively.

Temp. °F	75# psi	150# psi	300# psi
-20~100	140	275	720
200	125	250	650
300	115	230	595
400	110	200	550
500	85	170	515
600	70	140	485
650	60	125	475
700	-	110	465
750	-	95	460
800	-	80	450
850	-	65	445
900	-	50	440
950	-	35	385
1000	-	20	365
1050	-	-	360
1100	-	-	310
1150	-	-	235
1200	-	-	185
1250	-	-	140
1300	-	-	110
1350	-	-	85
1400	-	-	65
1450	-	-	50
1500	-	-	40

*P-T ratings for Gr. F321 of Group 2.4, for Class 75, 150, 300.

Temp.°F	400#	600#	900#
-20~100	960	1440	2160
200	865	1295	1945
300	795	1190	1785
400	735	1105	1655
500	690	1030	1550
600	650	975	1460
650	635	950	1425
700	620	930	1395
750	610	915	1375
800	600	900	1355
850	595	895	1340
900	590	885	1325
950	515	775	1160
1000	485	725	1090
1050	480	720	1080
1100	415	625	935
1150	315	475	710
1200	245	370	555
1250	185	280	420
1300	145	220	330
1350	115	170	255
1400	85	130	195
1450	70	105	155
1500	50	75	115

*P-T ratings for Gr. F321 of Group 2.4, for Class 400, 600, 900.

Temp.°F	1500#	2500#
-20~100	3600	6000
200	3240	5400
300	2975	4960
400	2760	4600
500	2580	4300
600	2435	4060
650	2375	3960
700	2330	3880
750	2290	3820
800	2255	3760
850	2230	3720
900	2210	3680
950	1930	3220
1000	1820	3030
1050	1800	3000
1100	1560	2600
1150	1185	1970
1200	925	1545
1250	705	1170
1300	550	915
1350	430	715
1400	325	545
1450	255	430
1500	190	315

*P-T ratings for Gr. F321 of Group 2.4, for Class 1500 and 2500.