3/4 hydraulic hose fittings

3/4 hydraulic hose fittings are the key parts of the hydraulic system to connect the hose and equipment, with a large diameter, high pressure resistance, adaptability and other characteristics, widely used in construction machinery, agricultural equipment, marine hydraulic systems and other fields.

The meaning and core characteristics of 3/4 hydraulic hose Fittings

3/4 Hydraulic Hose Fittings refers to standardized fittings with an inside diameter of 3/4 inch (19.05mm), in accordance with international standards such as SAE J517 (steel wire braided hose standard) and ISO 18752 (hose assembly specification).
Its core features include:
1. High-pressure capability: working pressure ranges from 25MPa to 100MPa, suitable for large hydraulic equipment (such as excavator hydraulic arms). 2;
2. Variety of sealing forms: supporting taper seal (JIC 37°), thread seal (NPT) or flange connection;
3. vibration-resistant design: heavy-duty ferrule or double O-ring structure to reduce the risk of leakage caused by high-pressure shock.

3/4 Main types of hydraulic hose Fittings

1. Categorized by connection

2. Categorized by material

Carbon steel nickel-plated: economical and durable, resistant to general corrosion (e.g., agricultural tractor hydraulic systems);
Stainless steel (316L): resistant to seawater, chemical corrosion (marine platforms, chemical equipment);
Alloy steel: ultra-high strength, suitable for mining machinery and other extreme conditions.

3. Categorized by structure

Straight through type: 3/4 interface at both ends, used to extend the pipeline;
90° elbow: compact design, reduce pipeline bending stress;
Three-way / four-way type: multi-way shunt, suitable for complex hydraulic circuits.

3/4 Hydraulic Hose Fittings Size Chart

Price list of 3/4 hydraulic hose fittings in different sizes

How to Identify 3/4 Hydraulic Hose Fittings

1. Dimensional verification
Caliper measurement: Thread O.D. ≈ 26.44mm (3/4” NPT) or hose I.D. ≈ 19.05mm;
Thread parameters:
NPT: 60° tapered thread, 14 TPI (teeth per inch);
BSPP: 55° parallel thread, 14 TPI.

2. Marking and Certification
Standard designation: Fittings are stamped “3/4 SAE J514”, “ISO 18752” or “DIN 20066”;
Pressure rating: e.g. “50MPa” indicates the maximum working pressure, and the plating marking “Ni” stands for nickel-plated treatment.

3. Tool Inspection
Thread gauge test: Use NPT or BSPP special gauge to verify that the taper matches the tooth type;
Pressure resistance test: Pressurize the hose to 1.5 times the working pressure (e.g. 75MPa) by hydraulic test bench to check the sealing.

Key Factors in Procurement Selection

1. Pressure level matching
Low pressure system (<21MPa): BSPP optional
Medium and high pressure systems (21-70MPa): JIC 37° recommended
Ultra-high pressure system (>70MPa): SAE flanges must be used.

2. Material Selection Guide
General environment: carbon steel galvanized
Corrosive environment: 316L stainless steel
High temperature environment: alloy steel

3. Installation space considerations
Compact space: 90° elbow is preferred
Long distance piping: straight-through type is more economical.
Complex circuits: three-way/four-way shunt

4. Quality Inspection
Size tolerance ± 0.05mm
Surface roughness Ra≤3.2μm
Pressure test 1.5 times the working pressure

Installation specification of 3/4 hydraulic hose Fittings

1. Preparation before installation
Cleaning treatment: Wipe the interface with acetone or special cleaner to ensure that there is no oil, rust slag;
Seal selection:
JICFittings: rely on taper compression, no additional sealant required;
NPTFittings: Wrap 34 layers of PTFE raw tape (clockwise) or apply anaerobic adhesive.

2. Installation steps (flanged Fittings as an example)
1. Align Flange: Ensure bolt holes are aligned, insert bolts and manually pre-tighten;
2. Cross-tighten: Increase the torque in 3 increments in diagonal order (e.g. final torque 120150 N-m);
3. Hose connection: Slip the hose into the Fittings core and snap with hydraulic pliers to standard compression (approx. 7% of hose OD);
4. System pressure test: start the hydraulic pump to gradually pressurize to the working pressure and observe no leakage for 30 minutes.

3. Key Precautions
Torque control: over torque will cause flange deformation (refer to SAE J518 standard);
Anti-coupling corrosion: Insulating gaskets are required between stainless steel Fittings and carbon steel piping;
Regular maintenance: check the bolt preload quarterly and replace the hoses every 2 years.

Conclusion:

3/4 hydraulic hose Fittings as a heavy-duty hydraulic system “blood vessel connector”, its reliability directly determines the safety of equipment operation. Proper selection (e.g. 316L stainless steel for marine environments) and installation (following SAE torque standards) can significantly extend service life. For ultra-high pressure or high-frequency pulsating conditions, we recommend contacting our engineers for a customized solution.

Frequently Asked Questions:

Threaded joints leak, how to check？

Check for damaged threads
Verify that the sealing material is adequate
Verify that the torque is adequate

Flange joint leakage, how to check？

Check the flatness of the flange surface
Verify that the seal is not deteriorated
Verify that the bolt preload is uniform

After-sales maintenance recommendations, what are they?

Check the condition of the joint every 500 working hours
Replace sealing elements once a year
Check for wear on the inside of the joint when flushing the system

2025 3/4 hydraulic hose fittings Product Showcase, Prices as low as $0.15

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