Hydraulic Hose Quality Control Throughout the Manufacturing Process

Hydraulic Hose Quality Control Throughout the Manufacturing Process

Hydraulic Hose quality is critical not only for engineers and machine manufacturers but also for us as a manufacturer. I’ve heard a lot of complaints over the last few years about the service life of the hydraulic lines that were installed on their machines, and how they didn’t last as long as they should have. Even though there are some explosive cases, some accidents occur, such as irregular damages, and this had a negative impact on their credit and wasted their time.

As a professional manufacturer of hydraulic rubber hoses, we understand our responsibility to provide high-quality products to our customers, and we regard qualified products as the lifeblood of our company, as well as our reputation in the industry.

To be honest, if a product can’t withstand scrutiny in its application, it will be phased out of the market.

As a result, in the following paragraphs, I will discuss our hydraulic rubber hose quality control in three sections:

Pre-production inspection of raw materials

Hydraulic rubber tubes are primarily made of polymer synthetic rubber reinforced with steel wire.

Raw rubber examination

Following the arrival of a new batch of raw rubber in our warehouse, some samples are sent to the laboratory (based on specific rules).

The hardness of raw rubber is then tested according to our standard, with a qualified result in the range of Shore A 82-85, and tensile strength of more than 12 MPa. These raw materials that fall short of our requirements must be returned or used for another purpose.

Steel wire examination

Following the purchase of a new batch of steel wire, we conduct a sample test in accordance with industry standards. Production accepts tensile strengths between 2450 and 2750 N. At the same time, the tensile must be within our tolerance to ensure that the working and burst pressures are met.

A study of the adhesive between rubber and steel wire

Before the raw materials being tested are used, this examination is a small simulation process. We vulcanize inner tube rubber and outer tube rubber with steel wire to determine how much adhesive is present between them and, ultimately, to ensure adhesion.

In addition, we inspect the properties of raw rubber during the vulcanization process to ensure that their quality is maintained under our supervision.

“‘After the main items have been tested, some forms must be completed and stored in our database to record the characteristics of this batch of raw material. “‘In the event of an unusual emergency, these data can be traced back.”‘

Craft node control in the middle of production

Make mandril preparations ahead of time.

We prepare soft or steel mandril the day before and dry it to ensure that it separates well from the inner tube while causing no damage to the inner tube.

Each mandril must be labeled with an ID card that can be traced during the manufacturing process.

Steel joint machine adjustment

Every two days, we adjust the steel joint machine. Every day, the difference in steel wire length is measured. Because of the tolerance in the XN(7N,8N,9N,10N,11N,12N) standard, it is possible to ensure an identical length before the braiding machine.

Steel wire reinforcement braid

To avoid more connections in braiding reinforcement, we will throw out steel wires less than 50 meters in braiding machines.

Spider tension is 0.5 kilograms higher than normal.

We adjust spider tension 0.5 kg higher than standard in braiding machines to ensure braiding cover is more compact and in good shape; it is higher than standard.

PLC automation controls the cold feeder extruder.

We use an advanced cold feeder extruder that is controlled by a PLC computer and has more power to extrude rubber tube in a good shape.

At room temperature, the shape returns to its original dimensions.

After extruding the inner tube, we allow it to recover its original dimensions in normal temperature for at least 4 hours before placing it in a cold machine at -35 °C for braiding.

Maintain our standard pitch and steel wire distances.

We keep track of pitch distance and steel wire distance in our braiding and spiraling machines as part of our standard, ensuring that the steel wire angle is kept under control.

“‘It is important to note that ID cards from various raw materials are grouped together in a buntch to refer to a single hose. “‘In the following test of the finished product, if a defect occurs, it is easy to track where errors occurred, and we will immediately correct that error.”‘

Post-production quality control of the finished product

The majority of strongflex finished hoses are tested to specific standards; our products meet SAE, ISO, DIN, and other industry standards. We have many professional institution certifications; if you want to learn more about them, go to the front page (certification section); you must consider us as a professional rubber hose supplier.

To return to the main topic, each finished hose will be tested against the specific technical parameter specified in the corresponding standard. The most important items are listed below.

Dimensional verification

Each hose must meet the dimensions specified for the hose type it belongs to. This is regarded as a post-production validation quality check.

Inner tube, reinforcement layer, and outer layer make up a hydraulic hose. The section of the three layer is three concentric circles in theory, but certain deviations can be tolerated due to influencing factors, so we strictly control deviations within standard limits.

Pressure proofing

After hydraulic hoses are finished, we test proof pressure at 1.8 times working pressure on EACH HOSE for one minute to ensure no leaks or defective hoses are shipped to our customers. The burst pressure must be 2-4.2 times working pressure.

Pressure burst test

The burst pressure test is a destructive test used to verify the hose’s safety factor. They’re put through their paces until the hoses can’t take it any longer. To pass, the pressure must be at least four times the working pressure.

Impulse test

One of the most important predictors of hose life is hydraulic hose impulse testing. To simulate common machine usage and on/off cycles, impulse testing creates high- and low-pressure pluses on assemblies.

Flexibility test in the cold:

Cold flexibility is tested to ensure that the hose’s flexibility is maintained even at low temperatures.

Absorption of oil test:

The purpose of the oil absorption test is to verify how well the hose cover performs in the event of oil contamination or in the selected fluid media.

Test for Ozone Resistance:

The presence of ozone in the air is a significant degrading factor for the outer layer, and it has a direct impact on the hose’s lifespan. If the outer layer is damaged or falls off, the reinforcement steel wire is susceptible to rusting, and the hose’s function will be lost. As a result, this test ensures that the hose cover is resistant to the effects of ozone.


You can see how we control the quality of our products during the entire manufacturing process from the description I provided above, and I believe that if you are an experienced guy, you will feel that we are on the same page; however, there must be some omissions and shortages in this article. In the coming days, I’ll add some details. But I believe that at the very least, this will increase consumer confidence in our product and service. Please do not hesitate to contact us; we are eager for a successful comunication.


Please feel free to contact us.