TYPE TESTS

GENERALS:

The pipe fittings perform two functions: the sealing and the anchorage of the connection pipes, by recovering their structural continuity to prevent the nut to be loosened from the body and the pipe to be disconnected from the pipe fitting.
The tests carried out in compliance with the RAILWAY SPECIFICATIONS FOR CLASS “A” PIPE FITTINGS are reported here below.

EXAMINED SAMPLES:

- Straight union for ø 25 copper pipe, 2 mm thick
- Straight union for ø 3/8” stainless steel pipe, 1.5 mm thick
- 150 mm pipe length both ø 25 in copper and ø 3/8” in stainless steel
- Female union and associated cap

• 1 - DISCONNECTION TEST UNDER TRACTION:

Detection of load causing the pipe fitting disconnection:
- ø 3/8” x 1.5 mm stainless steel pipe: 6300 N with 50 Nm tightening torque
- ø 25 x 2 mm copper pipe: 13600 N with 80 Nm tightening torque

• 2 - DISCONNECTION TEST UNDER HYDRAULIC PRESSURE:

The circuit is fed by progressively increasing the hydraulic pressure. This test has been carried out by tightening the nut according to the torque values specified in table 2 (page 2).
The applied test pressures have been 30 % higher than those specified in table 1 (page 2).

•3 -TIGHTNESS TEST:

10 min after having fed the samples under test with the pressures specified in table 1 (page 2) no pressure variation has been detected with respect to the initial one

• 4 - ENDURANCE TEST AT PULSATING PRESSURE:

106 cycles with 2 sec frequency pulsation from 0 bar to 55 bar have been carried out. Test executed on a ø 25 straight union

•5 - ENDURANCE TEST UNDER PRESSURE AND VIBRATION COMBINED EFFECTS:

The ø 25 straight union samples with copper pipe, with and without safety collar, have been fed at 55 bar constant pressure with SAE10 oil under the following conditions:
- Random frequencies from 20 Hz to 200 Hz
- Accelerations up to 10 g
- 10 hour test duration
- Ambient temperature

•6 - ENDURANCE TEST UNDER THERMIC VARIATIONS:

The samples under test have been fed at 10 bar pneumatic pressure and submitted to 10 thermal cycles by alternating the temperatures of -40°C and +140°C. A stabilization time of 8 hours has been waited for before each temperature change.
NOTE: Tests 4 and 5 have been carried out on the same samples.

SALT FOG TESTS

Carried out at AQM
Solution: deionized water + NaCI RPE 99.5% (50 g/l concentration).
Sample inclination in the chamber: 30°C.
Test temperature: 35°C
Test solution Ph: 6,9.
Total exposition duration: 2000 hours (with systematic visual inspections and relative intermediate documentation of the pipe fittings surface status).