BSP Male Captive Seal Plug Hydraulic Pipe Fitting

The material of BSP Male Captive Seal Plug Hydraulic Pipe Fitting is mainly composed of two parts: the plug body and the sealing ring.

【1】The material of the screw cap body

（1）Carbon steel

Most commonly used, with high strength and reasonable price. The surface is usually treated with zinc plating or nickel plating to prevent rust.

Working environment: General hydraulic systems, construction machinery, industrial equipment.

（2）Stainless steel 304 / 316L

Corrosion-resistant, does not rust. 316L is more resistant to salt spray and chemicals than 304.

Working environment: Marine environment, chemical industry, food and medicine, outdoor humid places.

（3）Brass

Water-resistant and air-resistant, but with lower strength than steel.

Working environment: water systems, low-pressure pneumatic, cooling circuits.

【2】Captive Seal

The sealing ring is an O-ring fixed in the groove on the end face of the BSP Male Captive Seal Plug Hydraulic Pipe Fitting. The common materials used are:

（1）NBR

Operating temperature: -40°C ~ +120°C

Features: The most versatile, resistant to mineral oil and hydraulic oil, and low in price.

（2）FKM

Operating temperature: -15°C ~ +200°C

Features: Resistant to high temperatures, resistant to chemicals, resistant to aging, with a slightly higher price.

How to choose the material?

When choosing the material for the BSP Male Captive Seal Plug Hydraulic Pipe Fitting, four factors should be considered: the working medium, temperature, environmental corrosiveness, and pressure.

（1）Working medium

For example, mineral hydraulic oil and lubricating oil. The material is selected as carbon steel with galvanization and is combined with NBR sealing rings.

If it's water or low-pressure air, brass or stainless steel 304 are both suitable, along with NBR sealing rings.

（2）Temperature

The working temperature ranges from -40°C to +120°C. The NBR sealing ring is universal and relatively inexpensive.

If the working temperature is -15°C to +200°C, the FKM sealing ring is more resistant to high temperatures, but it is more costly.

When the working temperature exceeds 200°C, special BSP Male Captive Seal Plug Hydraulic Pipe Fitting seals (such as silicone or metal seals) need to be used.

（3）Operating environment

For indoor and dry environments, choose carbon steel with galvanization. For outdoor damp conditions, the surface of carbon steel can be coated with yellow zinc, black zinc or nickel.

In high-salt-spray and coastal environments, stainless steel is a more suitable choice.

（4）Pressure

Standard hydraulic system (≤ 250 bar): Carbon steel, stainless steel, brass

High pressure (350 - 400 bar): Carbon steel or stainless steel, but brass is not suitable.

Ultra-high pressure (630 bar): Must be made of high-strength carbon steel