SEAMLESS MECHANICAL TUBING HOT FINISH WALL THICKNESS TOLERANCE

 

 

FOR TUBING PRODUCED- OUTSIDE DIAMETER AND WALL

    Wall Thickness Tolerance Percent Over and Under Normal
Wall Thickness Flange As Percent of Outside Diameter

Outside Diameter 1.500”

(38.09 mm) to 3.000 (76.20 mm)

Outside Diameter 3.000” (76.20 mm) to 5.999” (152.37 mm)
Outside Diameter 6.000” (152.40 mm) to 10.750” (273.05 mm)
15%
12.5%
10.0%
10.0%
15%
10.0%
7.5%
10.0%

 

Wall thickness tolerance may not be applicable to walls 9.199 inch (5.05 mm) and less’ consult manufacturer for wall tolerances on such tube sizes.

11" and over wall tolerance is +/- 12.5%

 

MAXIMUM DEPTH LIMIT IF SURFACE IMPERFECTIONS OF O.D. AND I.D. – TUBING

 

The following table shows the permissible depth of surface Imperfections. Determination should be made by measuring the actual diameter or wall thickness at the place of imperfection, filling it out, and remeasuring.

SPECIFIED O.D.
HOT FINISHED
1.4999
.010
1.500/1.999
.013
2.000/2.499
.015
2.500/2.999
.018
3.000/3.499
.020
3.500/3.999
.023
4.000/4.499
.025
4.500/4.999
.028
5.000/5.499
.030
5.500/5.999
.035
6.000/6.499
.038
6.500/6.999
.040
7.000/7.499
.043
7.500/7.999
.045
8.000/8.499
.050
8.500/8.499
.055
9.000/9.499
.060
9.500/9.999
.065
10.000/10.499
.070
10.500/10.750
.075
10.750/11.000
----------

 

 

Outside Diameter Tolerances for Round Hot Finish a.b.c.

 

Outside Diameter Size Range,

In. (mm)

Over

Outside Diameter Tolerance. in. (mm)

Under

Up to 2.99 (76.17)
0.020 (0.51)
0.020 (.051)
3.000-4.499 (76.20-114.27)
0.025 (0.64)
0.025 (0.64)
4.500-5.999 (114.30-152.37)
0.031 (0.79)
0.031 (0.79)
6.000-7.499 (152.40-190.47)
0.037 (0.94)
0.037 (0.94)
7.500-8.999 (190.50-228.57)
0.045 (1.14)
0.045 (1.14)
9.000-10.750 (228.6-273.05)
0.050 (1.27)
0.050 (1.27)
11.000 or larger
+/- 1%
+/- 1%

a.. Diameter to tolerance are not applicable to normalized and tempered or quench and tempered conditions.

 

b. The common range of sizes of hot finished tubes is 1% in. (38..1 mm) to 10-3/4 in. (273.00 mm) outside diameter with wall thickness at least 3% or more of outside diameter, but not less than 0.095 in. (2.41 mm).

 

c. Larger sizes are available; consult manufacturer for sizes and tolerances.

 

Additional Quality
OD, Inches
Tolerances, Inches
Up to 2,000
Incl.
.010
Over
2.000 - 3.000
Incl.
.015
Over
3.000 - 4.000
Incl.
.020
Over
4.000 - 5.000
Incl.
.025
Over
5.000 - 6.000
Incl.
.030
Over
6.000 - 7.000
Incl.
.035
Over
7.000 - 8.000
Incl.
.040
Over
8.000 - 9.000
Incl.
.045
Over
9.000 - 10.000
Incl.
.050
Over
10.000 - 11.000
Incl.
.055
Over
11.000 - 12.000
Incl.
.060
Over
12.000 - 12.5000
Incl.
.065

 

 

 

Size Limits
Maximum Curvature in any 3 ft. In. (mm)
Maximum Curvature in Total Lengths, In. (mm)
Maximum Curvature In Total Lengths 3 ft or 1 m
OD 5 in. (127.0 mm) and smaller. Wall thickness over 3% of OD but not over 0.5 in. (12.7 mm)
0.030 (0.083)
0.030 x (no. of ft of length/3) (0.083 x no. of m of length)
Ratio of 0.010 in./ft or 0.83 mm/m
OD 5 in. to 8 in. (127.0 to 203.2 mm), incl. Wall thickness over 4% of OD but not over 0.75 in. (19.0 mm)
0.045 (1.25)
0.045 x (no. of ft of length/3) (1.25 x no. of m of length)
Ratio of 0.015 in./ft or 125 mm/m
OD 8 in. to 12-3/4 in. (203.2 mm to 323.8 mm), incl. Wall thickness over 4% of OD but not over 1.0 in. (25.4 mm)
0.060 (1.67)
0.060 x (no. of ft of length/3) (1.67 x no. of m of length)
Ratio of 0.020 in./ft or 16.7 mm/m

 

 

Length Tolerances for Round Hot Finished Tubing

 

NOTE- The producer should be consulted for the length tolerances for tubes produced by liquid –or air quenched heat treatment.

Length, ft. (in.)
Outside Diameter, in. (mm)
Tolerance , In. (mm) Over
Tolerance, in. (mm) Under
4 (1.2) and under
Up to 2 (50.8), incl.
1/16 (1.6)
0
4 (1.2) and under
Over 2 to 4 (50.8 to 101.6), incl.
3/32 (2.4)
0
4 (1.2) and under
Over 4 (101.6)
1/8 (3/2)
0
Over 4 to 10 (1.2 to 3.0), incl.
Up to 2 (50.8), incl.
3/32 (2.4)
0
Over 4 to 10 (1.2 to 3.0), incl.
Over 2 (50.8)
1/8 (3/2)
0
Over 10 to 24 (3.0 to 7.3), incl.
All sizes
3/16 (4.8)
0

 

 

 

MACHINING ALLOWANCES FOR ALLOY MECHANICAL TUBING

OD
Commercial Quality FOR H.F. (Per Size)
Magnaflux Quality FOR H.F. (Per Size)
½” to 1-1/2”
.015"
.040”
1-1/2”
.025”
.050”
Over 3” to 4”
.030”
.055”
Over 4-1/2” to 5-1/2”
.035”
.060”
Over 5-/2” to 6-1/2”
.040”
.065”
Over 6-1/2” to 8”
.050”
.075”
Over 8” to 10”
.070”
.095”

NOTE-

(a) Same as I.D as O.D

(b) For magnaflux quality .025" per side was added for C.D.

(c) Over 10" consult Carbon & Alloy Steel Corp.

(d) Above allowances do not include heat treated material

 

 

 

 

 

MACHINING ALLOWANCES FOR TUBING FROM WAREHOUSE STOCK

 

The following procedure may be used to determine the proper warehouse stock size (O.D. and wall thickness) of Cold Drawn Seamless or Buttweld Steel Tubing with sufficient allowance for machining based in chucking true to O.D.

 

A= Machined O.D. (Maximum)

B= Machining allowance, O.D. or I.D. per side

Under 1-1/2” O.D. .020”

1-1/2” to 3” Excl. 0.40”

3” to 5-1/4” Excl. 0.60”

5-1/2” to 8” Excl. 0.80”

 

C= Camber in length of part, ratio per foot

Under 5” O.D. .020”

5” to 8” Excl. .030”

8” to 10-3/4” .040”

Calculated O.D. = A + B + C

D= Machined I.D. (Minimum)

E = Outside Diameter Tolerance

F = Percent of Wall Thickness Tolerance

 

Stock Size O.D. –When the calculated O.D. is not shown as available in the stock list use the stock size O.D. listed which is next larger than the calculated O.D.

 

Calculated I.D. = D – (B + C)

Calculated Wall Thickness (Stock Size O.D. + E – Calculated I.D.) (1.00 + F)

 

Stock Size Wall Thickness – When calculated wall thickness is not shown as available in the stock size O.D. above, use the ctock size wall thickness

listed which is next heavier.

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