飞机液压系统管路和接头

Basic Aircraft Systems — Hydraulic System
RIGID FLUID LINES
2. Rigid lines in modern aircraft Corrosion-resistant steel tubing : Corrosion-resistant steel tubing, either annealed or 1/4 hard, is used in high pressure systems (3,000 psi)
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Basic Aircraft Systems — Hydraulic System
RIGID FLUID LINES
2. Rigid lines in modern aircraft Titanium alloy tubing :

Do not use titanium tubing and fittings in any oxygen system assembly. Titanium and titanium alloys are oxygen reactive. If a freshly formed titanium surface is exposed in gaseous oxygen, spontaneous combustion could occur at low pressures.
Basic Aircraft Systems — Hydraulic System
RIGID FLUID LINES
2. Rigid lines in modern aircraft Titanium alloy tubing :

This type of tubing and fitting is used extensively in transport category and high performance aircraft hydraulic systems for pressures above 1,500 psi. Titanium is 30 percent stronger than steel and 50 percent lighter than steel. Cryofit fittings（冷装配接头） or swaged fittings（型锻接头） are used with titanium tubing.
However, as a rule, rigid tubing is used in: Stationary applications Long, relatively straight runs Systems that typically utilize rigid tubing include fuel, oil, oxygen, and instrument systems.

Basic Aircraft Systems — Hydraulic System RIGID FLUID LINES
2. Rigid lines in modern aircraft Corrosion-resistant steel tubing : Another benefit of corrosion-resistant steel tubing is that it has a higher tensile strength which permits the use of tubing with thinner walls. As a result, the installation weight is similar to that of thicker-walled aluminum alloy tubing.
Basic Aircraft system Fittings and Lines of Hydraulic System
Basic Aircraft Systems — Hydraulic System
RIGID FLUID LINES
A single aircraft typically contains several different types of rigid fluid lines. Each type of line has a specific application.

Applications include high pressure hydraulic, pneumatic and oxygen systems. Corrosion-resistant steel is also used in areas that are subject to physical damage from dirt, debris, and corrosion caused by moisture, exhaust fumes, and salt air. Such areas include flap wells and external brake lines.
Basic Aircraft Systems — Hydraulic System
RIGID FLUID LINES
MATERIAL 1. Rigid lines in early aircraft Annealing is accomplished by heating the tube until it is red hot and then quenching in cold water. When working on an aircraft that has copper tubing, the tubing should be annealed each time it is removed. Furthermore, copper lines must be regularly inspected for cracks, hardness, and general condition.

One way to ensure that a replacement is made of the same material is to compare the code markings on the replacement tube to those on the original. If the manufacturer's markings are difficult or impossible to read, an alternative method of identification must be used.
Basic Aircraft Systems — Hydraulic System RIGID FLUID LINES
MATERIAL 2. Rigid lines in modern aircraft Aluminum tubing : lines made of 5052-O aluminum alloy — Low pressure fuel and oil and medium pressure (1,000 to 1,500 psi) hydraulic and pneumatic systems. This alloy, even in its annealed state, is about one and three-quarters times stronger than half-hard, commercially pure aluminum. Occasionally, 2024-T aluminum alloy is used for fluid lines because of its higher strength. However, it is not as flexible and, therefore, is more difficult to bend and flare without cracking.
Basic Aircraft Systems — Hydraulic System RIGID FLUID LINES
MATERIAL 1. Rigid lines in early aircraft Many fluid lines used in early aircraft were made of copper tubing. However, copper tubing proved troublesome because it became hard and brittle from the vibration encountered during flight, and eventually failed. To help prevent failures and extend the life of copper tubing, it must be periodically annealed to restore it to a soft condition.

Basic Aircraft Systems — Hydraulic System
RIGID FLUID LINES
Identification of tube material Repairs to aircraft tubing must be made with materials that are the same as the original, or are an approved substitute.
Basic Aircraft Systems — Hydraulic System
RIGID FLUID LINES
MATERIAL 2. Rigid lines in modern aircraft Aluminum tubing : Aluminum alloy tubes are identified in a number of ways. on larger tubes, the alloy designation is stamped directly on the tube's surface. on small tubing, the alloy designation is typically identified by a colored band. These color bands are no more than 4 inches wide and are painted on the tube's ends and mid section. When a band consists of two colors, one-half the width is used for each color. [Figure 10-1]
Basic Aircraft Systems — Hydraulic System
RIGID FLUID LINES
MATERIAL 2. Rigid lines in modern aircraft Aluminum alloy （铝合金） Corrosion-resistant steel （耐腐蚀钢） Titanium alloy （钛合金） Aluminum tubing: Aluminum tubing comes in a variety of alloys. pure aluminum tubing made from 1100-H14 (half-hard), or aluminum alloy 3003-H14 (half-hard) — low pressure systems (below 1,000 psi) such as those used for instrument air or ventilating air