What is the material of the hydraulic pipe?

Ordinary hydraulic oil has no corrosiveness to steel pipes and steel joints, so carbon steel joints are commonly used in hydraulic systems. Pipes connecting drinking water or pure water should not use ordinary carbon steel. In the past, brass pipes were used as a rule for compressed air, as compressed air would carry water and accumulate in the pipes. If carbon steel pipes were used, they would corrode the pipes. Advanced air compression machinery no longer produces moisture, so this rule also loses its significance

Chemical equipment pipelines usually transport various corrosive fluids and require frequent use of solvents or water flushing. Therefore, ordinary chemical pipelines must be made of stainless steel.

When considering the corrosiveness of the medium. The main consideration should be the relationship between pipeline seals and the medium. Due to its compatibility with ordinary hydraulic oil, nitrile rubber is widely used in hydraulic systems. At a certain temperature, nitrile rubber can also be compatible with synthetic acetaldehyde, sugar based chemical liquids (HEPG), and liquids derived from plants. However, nitrile rubber (NBR) is not suitable for contact with acidic media, benzene, or synthetic oil at high temperatures. In this case, fluororubber (FKM) should be used. On the contrary, methane and refrigeration ammonia can only be miscible with nitrile rubber (NBR). Therefore, most chemical stainless steel pipelines are rigid sealed.

When selecting a pipe joint, it is important to know the nominal pressure of the joint. The nominal pressure is a standard parameter and is numerically equivalent to the maximum working pressure of the system. According to DIN3859-3 (ISO19879), the maximum working pressure shall meet 4 times of the static insurance parameters and 1.33 times of the dynamic insurance coefficient, that is, the blasting pressure measured by the blasting inspection is divided by 4 and the maximum pulse pressure is divided by 1.33. The smaller of the two values is defined as the maximum working pressure.

When selecting pipe joints, request that the maximum working pressure of each joint be at least equal to the maximum set working pressure of the entire hydraulic system's working state, not only considering the outlet pressure of the pump, but also considering the starting pressure of the overflow valve. Therefore, when designing complex hydraulic pipelines, it is best to use on-site measurement methods to determine the practical pressure. The working pressure of the system has been determined, and the maximum working pressure of each selected pipe joint needs to be checked afterwards.

The maximum working pressure of a pipe joint can vary depending on the sealing method or temperature changes: selecting an elastic seal for the same pipe joint will result in a higher working pressure than a rigid seal.

The national standard specification sets a safety factor of 4 times. The reason is to consider the errors that may occur during practical design, pipe joint devices, and equipment operation, as well as the instability of the system's working state. In order to ensure that the system will not be completely paralyzed during operation, the safety factor for nominal pressure is set higher.