Page 28 - FlexitallicCatalog2010

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29
USEFUL TECHNICAL DATA
TORQUE REQUIRED TO PRODUCE BOLT STRESS
TORQUE DATA FOR USE WITH ALLOY STEEL STUD BOLTS
Load in Pounds on Stud Bolts when Torque Loads are Applied
1
/
4
20
.185
.027
4
810
6
1215
8
1620
5
/
16
18
.240
.045
8
1350
12
2025
16
2700
3
/
8
16
.294
.068
12
2040
18
3060
24
4080
7
/
16
14
.345
.093
20
2790
30
4185
40
5580
1
/
2
13
.400
.126
30
3780
45
5670
60
7560
9
/
16
12
.454
.162
45
4860
68
7290
90
9720
5
/
8
11
.507
.202
60
6060
90
9090
120
12120
3
/
4
10
.620
.302
100
9060
150
13590
200
18120
7
/
8
9
.731
.419
160
12570
240
18855
320
25140
1
8
.838
.551
245
16530
368
24795
490
33060
1
1
/
8
8
.963
.728
355
21840
533
32760
710
43680
1
1
/
4
8
1.088
.929
500
27870
750
41805 1000
55740
1
3
/
8
8
1.213 1.155
680
34650 1020 51975 1360
69300
1
1
/
2
8
1.338 1.405
800
42150 1200 63225 1600
84300
1
5
/
8
8
1.463 1.680
1100 50400 1650 75600 2200 100800
1
3
/
4
8
1.588 1.980
1500 59400 2250 89100 3000 118800
1
7
/
8
8
1.713 2.304
2000 69120 3000 103680 4000 138240
2
8
1.838 2.652
2200 79560 3300 119340 4400 159120
2
1
/
4
8
2.088 3.423
3180 102690 4770 154035 6360 205380
2
1
/
2
8
2.338 4.292
4400 128760 6600 193140 8800 257520
2
3
/
4
8
2.588 5.259
5920 157770 8880 236655 11840 315540
3
8
2.838 6.324
7720 189720 11580 284580 15440 379440
NOMINAL
NUMBER
DIAMETER
AREA
DIAMETER
OF
AT ROOT
AT ROOT
BOLT
THREADS
OF ThREAD
OF ThREAD
(lnches)
(Per Inch)
(Inches)
Sq. Inch
STRESS
30,000 PSI
45,000 PSI
60,000 PSI
Torque
Compression
Torque
Compression
Torque
Compression
Ft/lbs
lbs.
Ft/lbs
lbs.
Ft/lbs
lbs.
Reprinted with permission of Crane Co. (Page 383, Crane No.60 Valve Catalog.)
The torque or turning effort required to produce a certain stress in bolting is dependent upon a number of conditions, some of which are:
1.
Diameter of bolt.
2.
Type and number of threads on bolt.
3.
Material of bolt.
4.
Condition of nut bearing surfaces.
5.
Lubrication of bolt threads and nut bearing surfaces.
Generally, standard Flexitallic spiral wound gaskets will require a minimum of 30,000 psi bolt stress for proper gasket seating. However, it is
the users responsibility to follow ASME Code calculations, and to ensure that sufficient pre-load is applied to withstand internal pressure,
properly seat the gasket, and compensate for the effects of bolt relaxation.
The table below reflect the results of many tests to determine the relation between torque and bolt stress. Values are based on steel bolting well
lubricated with a heavy graphite and oil mixture.
TABLE
20