News Details

1、 EN853 standard core parameters and structural analysis

The EN853 standard is a technical specification for steel wire braided reinforced hydraulic rubber hoses developed by the European Institute for Standardization. Its core structure consists of an inner rubber layer, a steel wire braided reinforcement layer, and an outer rubber layer. The inner rubber layer adopts oil resistant synthetic rubber, which needs to meet the long-term transportation requirements of mineral oil, polyethylene glycol based hydraulic oil and other media, and the volume change rate should not exceed 25% at a high temperature of 100 ℃. The reinforcement layer achieves pressure bearing through single-layer or double-layer steel wire weaving, with 1SN type being single-layer weaving and 2SN type being double-layer weaving. The blasting pressure needs to reach more than 4 times the working pressure. For example, the working pressure of a 1SN type hose with an inner diameter of 6.3mm is 46MPa, and the burst pressure needs to be ≥ 184MPa.

 

The outer rubber layer is made of black wear-resistant and weather resistant synthetic rubber, which has the characteristics of ozone resistance and UV resistance, and can still maintain flexibility in a low temperature environment of -40 ℃. The standard stipulates that the small bending radius should meet 8-10 times the outer diameter. For example, the 2SN type hose with an inner diameter of 25mm has a small bending radius of 300mm to avoid excessive bending and breakage of the steel wire weaving layer. Qingdao Chuangjia Rubber and other enterprises have obtained ISO 1436 certification to ensure that their products meet durability assessment requirements such as static pressure testing and pulse testing.

 

2、 Crimping process and assembly quality control

The crimping process directly affects the sealing and reliability of the hose assembly. The EN853 standard requires that the stripping length and clamping amount of the joint and hose be controlled when crimping. For example, the stripping length of the 2SN hose should be accurate to ± 2mm, and the axial tensile strength of the joint and hose after crimping should be ≥ 25kN. The sleeve type joint is sealed through a three part structure: the cone surface of the joint body and the outer blade of the sleeve form a rigid seal, the inner blade bites into the steel pipe to form a mechanical lock, and the tightening torque of the nut should be controlled within the range of 35-45N · m.

 

Assembly testing includes static pressure test and pulse test. The static pressure test is conducted at 1.5 times the working pressure for 60 seconds, with no leakage required; The pulse test was cycled 150000 times under a pressure of 16.25 MPa to simulate the actual working conditions of the excavator hydraulic system. For example, a test conducted by a construction machinery factory showed that the hydraulic system of an excavator using EN853 2SN assembly had a hose length change rate of only -1.2% after 2000 hours of continuous operation, far below the standard requirement of ± 4%.

 

3、 Application scenarios and failure case analysis

In the hydraulic support system of coal mines, EN853 hoses need to withstand an instantaneous impact pressure of 63MPa. A certain mine once caused the support to lose control due to the use of non-standard hoses. After testing, it was found that the thickness of the outer rubber layer of the hose was only 70% of the standard value, and the weaving density of the steel wire was insufficient, which ultimately led to a decrease in blasting pressure. The standard stipulates that the thickness of the outer adhesive layer should be ≥ 2.5mm, and the weaving density of the steel wire should be ≥ 85%.

 

In the field of construction machinery, the hydraulic pipeline of excavator boom often adopts EN853 1SN assembly. A certain brand of excavator experienced hose cracking in extremely cold areas. After analysis, it was found that the outer rubber layer did not pass the -40 ℃ low-temperature bending test, resulting in cracking of the inner lining layer. The standard requires that after bending a radius of 200mm at -40 ℃, a verification pressure test must be conducted to restore room temperature.

 

Failure cases show that 70% of early damage is due to improper installation. Due to the bending radius of the hose being smaller than the standard value, a crane at a certain port experienced fatigue fracture of the steel wire weaving layer, resulting in hydraulic oil leakage and causing a fire. The standard clearly stipulates that the root of the hose joint must retain a straight section of ≥ 6 times the outer diameter to avoid bending stress concentration. In addition, pipe clamps should be installed on straight sections with a spacing of no more than 1.5m to prevent hose vibration and wear.

 

4、 Standard Evolution and Industry Trends

The EN853 standard has undergone multiple revisions, with the 2025 version increasing the number of pulse tests to 200000 and adding a new biodiesel corrosion resistance test. The fusion trend between ISO 1436 and EN 853 is evident, with R2ATS and 1SN models being fully compatible in terms of size, but the pressure rating is based on EN 853. The industry is upgrading from wire weaving to wire winding technology, for example, the EN 856 4SP hose adopts a four layer winding structure, with a working pressure of up to 60MPa, suitable for ultra-high pressure scenarios such as deep-sea drilling platforms.

 

Intelligent manufacturing drives the innovation of crimping technology. A certain enterprise has introduced an AI visual inspection system, achieving a crimping error of ≤ 0.1mm and reducing the defect rate from 3.2% to 0.5%. At the same time, breakthroughs have been made in the application research of bio based rubber materials. The polylactic acid based inner rubber layer developed by a certain laboratory not only maintains oil resistance but also reduces carbon footprint by 40%, which meets the requirements of EU environmental regulations.