SHF - 8103 Red Bluff Rd - Pasadena TX 77507

832 456 2000

TUBE SELECTION

Suitable tubing selection is essential in performance of tubing system. When selecting tubing material, size and wall thickness, customer must consider pressure, flux (flow), temperature, environment and compatibility of system.


Consideration facts at the selection of tube:


Quality of the tube materials & manufacturing method.
Thickness and outer diameter of tube.
Surface treatment of tube.
Hardness of tube.
Concentricity of tube.

TUBE BENDING

Tubing must have a minimum straight length before the start of any bend when inserting the tube into a SUPERLOK Tube Fitting. Tubing where the minimum straight length is not adhered can result in leakage and jeopardize the integrity of the system. See the chart below for minimum straight lengths.


Requirements for quality Tubing Material

​Tubing must be free of surface imperfections and suitable for Bending.

Pressure coefficient for tubing as it relates to temperature change.

Tube O.D. (inch)
 1/8  3/16  1/4  5/16  3/8  1/2  5/8  3/4  7/8  1
L(mm)
12.70 18.25 19.05 20.63 22.20 23.81 30.16 31.75 33.30 38.10

L: The straight line length of tubing from the ending part of tubing to the begining part of bending


THE REQUIREMENTS FOR TUBE QUALITY OF THE MATERIAL

Carbon Steel Tubing


ASTM A179 or equivalent.
Carbon steel tubing for an oil pressure usage of high quality, annealed and seamless.
Maximum hardness : HRb72.
Tubing must be free from scars and shall be suitable for bending and expansion works.


Copper Tubing


ASTM B65, B75 or equivalent.
Copper tubing of high quality, annealed and seamless.


Stainless Steel Tubing


ASTM A213, A269 or A632 or equivalent.
Stainless steel tubing for an oil pressure usage of high quality, annealed and seamless. (316, 304, 321,etc.)
Hardness : below HRb 80.
Tubing must be free from scars and shall be suitable for bending and expansion works.

A PRESSURE GRADE COEFFICIENT OF TUBING OWNING TO TEMPERATURE CHANGE

°F
°C
COPPER
304SS
316SS
MONEL
200
93
0.80
1.00
1.00
0.88
400
204
0.50
0.93
0.96
0.79
600
316
-
0.82
0.85
0.79
800
427
-
0.76
0.79
0.76
1000
538
-
0.69
0.76
-
1200
649
-
0.30
0.37
-

Multiply the allowable working pressure in Table 2, 3, 4, 5 by the coefficient in Table1 in order to decide allowable pressure at high temperature. (See page Technological Information)


EXAMPLE


SUS316


(3/8" O.D of tube) X (0.049" wall thickness)
1200°F 4800 psi X 0.37 = 1776 psi


The applicable operation pressure of SUS 316 tubing for wall thickness: 3/8" O.D X 0.049" , is 1776 psi at 1200°F