ELECTRIC RESISTANCE WELDED TUBING
Square and Rectangular Tolerances
ASTM A-513
|
Largest Nominal Outside
Dimension, Inches |
Wall Thickness,
Inch |
Outside Tolerance at All
Sides at Corners, Inch Plus and Minus |
|
3/16 to 5/8 incl.
|
0.020 to 0.083 incl.
|
0.004
|
|
Over 5/8 to 1-1/8 incl.
|
0.025 to 0.156 incl.
|
0.005
|
|
Over 1-1/8 to 1-1/2 incl.
|
0.025 to 0.192 incl.
|
0.006
|
|
Over 1-1/2 to 2 incl.
|
0.032 to 0.192 incl.
|
0.008
|
|
Over 2 to 3 incl.
|
0.035 to 0.259 incl
|
0.010
|
|
Over 3 to 4 incl.
|
0.049 to 0.259 incl.
|
0.020
|
|
Over 4 to 6 incl.
|
0.065 to 0.259 incl.
|
0.020
|
|
Over 6 to 8 incl.
|
0.185 to 0.259 incl.
|
0.025
|
NOTE: Measurements should be taken at 2 inches from either end of tube.
CONVEXITY and CONCAVITY: Tubes having two parallel sides are also measured in the center of the flat sides for convexity and concavity. This tolerance applies to the specific size determined at the corners and is measured on the following basis:
|
Largest Nominal Outside
Dimension, Inches |
Tolerance Plus and Minus,
Inches |
|
2-1/2 and under
|
0.010
|
|
Over 2-1/2 to 4
|
0.015
|
|
Over 4 to 8
|
0.025
|
WALL TOLERANCE
Wall thickness tolerance on square and rectangular tubing is normally plus or minus 10 percent of the nominal wall. This tolerance exceeds the round tubing wall tolerance since stresses involved in forming round tubing into required square or rectangular sections cause wall deformation.
RADII OF CORNERS
The standard radius is established in accordance with the following table. Special radii may be obtained by arrangement between purchaser and producer. The slight flattening of the radius is more pronounced in heavier wall tubing.
|
Squares and Rectangles
Made From Tubes Whose Diameters Range From Inches |
Wall
Thickness B.W. Ga. and Dec. Inches |
Radius, Inches
|
|
1/2 to 1-1/2 incl.
|
22 (0.028)
|
1/32 to 1/16
|
|
1/2 to 2-1/2 incl.
|
20 (0.035)
|
1/32 to 1/16
|
|
1/2 to 4 incl.
|
18 (0.049)
|
3/64 to 5/64
|
|
1/2 to 4-1/8 incl.
|
16 (0.065)
|
1/16 to 7/64
|
|
3/4 to 4-1/8 incl.
|
14 (0.083)
|
5/64 to 1/8
|
|
Over 4-1/8 to 6 incl.
|
14 (0.083)
|
3/16 to 5/16
|
|
1 to 4-1/8 incl.
|
13 (0.095)
|
3/32 to 5/32
|
|
Over 4-1/8 to 6 incl
|
13 (0.095)
|
3/16 to 5/16
|
|
1-1/4 to 4 incl.
|
12 (0.109)
|
1/8 to 13/64
|
|
Over 4 to 6 incl.
|
12 (0.109)
|
3/16 to 5/16
|
|
1-1/4 to 4 incl.
|
11 (0.120)
|
1/8 to 7/32
|
|
Over 4 to 6 incl.
|
11 (0.120)
|
7/32 to 7/16
|
|
2 to 4 incl.
|
10 (0.134)
|
5/32 to 9/32
|
|
Over 4 to 6 incl.
|
10 (0.134)
|
7/32 to 7/16
|
|
2 to 4 incl.
|
9 (0.148)
|
3/16 to 5/16
|
|
Over 4 to 8 incl.
|
9 (0.148)
|
7/32 to 7/16
|
|
2 to 8 incl.
|
8 (0.165)
|
1/4 to 1/2
|
|
2 to 8 incl.
|
7 (0.180)
|
1/4 to 1/2
|
|
2-1/2 to 4 incl.
|
6 (0.203)
|
5/16 to 9/16
|
|
Over 4 to 8 incl.
|
6 (0.203)
|
5/16 to 9/16
|
|
2-1/2 to 8 incl.
|
5 (0.220)
|
3/8 to 5/8
|
|
2-1/2 to 8 incl.
|
4 (0.238)
|
3/8 to 5/8
|
|
2-1/2 to 8 incl.
|
3 (0.259)
|
3/8 to 5/8
|
The above tolerances apply to grade MT 1010 and grade MT 1020 steel only. Tolerances in other grades are subject to arrangement between purchaser and producer.
SQUARENESS OF SIDES
b = Tolerance for out-of-square
c = Length of longest size
c = 2 inch
± b = 2 x 0.006 inch = 0.012 inch
TWIST
|
Longest Side, Inches
|
Twist Permissible in 3 Ft., in Inches
|
|
Under 1/2
|
0.032
|
|
Over 1/2 to 1-1/2
|
0.050
|
|
Over 1-1/2 to 2-1/2
|
0.062
|
|
Over 2-1/2 to 4 incl.
|
0.075
|
|
Over 4 to 6 incl.
|
0.087
|
|
Over 6 to 8 incl.
|
0.100
|
STRAIGHTNESS
Commercial tolerance for straightness is 1/16 inch in three feet.