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TUBE FITTINGS

INTRODUCTION OF TUBE FITTINGS

Discover the tube fittings, engineered with precision under rigorous quality control measures to ensure unparalleled reliability. With effortless assembly that requires no specialized tools, making connections is swift and seamless – simply insert and tighten the nuts.

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Tube fittings are purposefully designed for integration within instrumentation, process, and control systems across various industries, including chemical, petroleum, power generation, and pulp and paper plants. Their versatility extends to numerous other applications where premium tube fittings are essential for optimal performance.

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CONSTRUCTION OF TUBE FITTINGS

Tube fittings consist of four meticulously crafted components: the body, nut, front ferrule, and back ferrule.

 

When the nut is screwed onto the body, it tightens against the tapered area, compressing the tube tightly against the edge by inward curling. Positioned between the body and nut, the back ferrule plays a crucial role. As the front ferrule rolls, the back ferrule also rolls up, securely biting into the tube, ensuring a leak-free connection between the tube and the fitting.

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The innovative twin ferrule design of the tube fittings ensures leak-proof sealing by transmitting assembly motion axially through the tubing. This unique approach prevents any radial movement of the tubing during assembly, preserving the tube's mechanical integrity and eliminating stress. Achieved through precise tolerance control in machining, surface smoothness, and part hardness, every component of the tube fittings contributes to this seamless integration. As a result of this meticulous swaging action, the tube fittings become mechanically integrated with the connected tube, ensuring robust and reliable performance.

TECHNICAL DATA

MATERIALS

FITTING MATERIALS

Tube fittings are crafted from a variety of durable materials, including stainless steel (typically SS316), brass, and alloy steel (such as Monel or other alloys).

SUITABLE TUBING MATERIALS

Tube fittings are compatible with various tube specifications, including stainless steel tubes meeting ASTM A269 or A213 standards, such as TP304 and TP316, or equivalent options like SUS304TP and SUS316TP according to JIS G3459. It's crucial to select the appropriate wall thickness based on operating pressure, temperature, and shock conditions. Fully annealed tubing is recommended for optimal performance, and stainless steel tubing with a Rockwell B80 hardness or less is preferred for use with the tube fittings.

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Tubing

Choosing the right tubing is critical for the optimal performance of a tubing system, especially when it comes to ensuring safety, reliability, and leak-free seals with tube fittings. S-LOK tube fittings excel when paired with high-quality tubing, emphasizing the importance of considering tubing as a crucial fitting component. When making decisions about tubing material, size, and wall thickness, customers must take into account various factors such as pressure, flow, temperature, environment, and system compatibility to enhance the effectiveness and longevity of tube fittings.

​General Guidelines.

  1. A crucial aspect for achieving leak-free seals with tube fittings is the surface quality of the tubing. It's imperative that the tubing surface is smooth and free from scratches, draw marks, flat spots, or any dirt accumulation.

  2. Welded tubing should exhibit a seamless outside diameter without any visible poor bead, ensuring compatibility and effectiveness when paired with tube fittings.

  3. Thermal compatibility and corrosion resistance rely heavily on the choice of tubing and fitting material. Both tubing and material must be compatible with the process fluid, operating temperature, and environmental conditions, enhancing the reliability of tube fittings.

  4. Maintaining the proper balance between tubing and fitting material hardness is essential for effective sealing. In cases where both tubing and fittings share the same material, ensuring that the metal tubing is fully annealed is vital for optimal performance of tube fittings.

  5. Selecting tubing hardness in accordance with specified guidelines ensures the seamless integration and functionality of tube fittings, promoting efficient operation and longevity.

  6. Avoiding extremes in wall thickness is paramount to prevent potential issues. Opting for a wall that is neither too thin, which risks collapse, nor too thick, which may impede proper deformation by the ferrule action, ensures optimal performance of tube fittings. The selection process should consider factors such as pressure, temperature, shock, and vibration to enhance the reliability of tube fittings.

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When selecting tubing for use with tube fittings, several key factors should be considered:

  • Assess the quality of the tube material and the method of manufacturing to ensure reliability and performance.

  • Take into account the hardness of the tube, ensuring it aligns with compatibility requirements for tube fittings.

  • Consider the surface treatment of the tube, aiming for smoothness and cleanliness to facilitate proper sealing with tube fittings.

  • ay attention to the outer diameter (O.D) and tolerance of the tube to ensure compatibility and secure fitting with tube fittings.

  • Evaluate the wall thickness and tolerance of the tube, keeping in mind the requirements for optimal performance and durability of tube fittings.

  • Check the concentricity of the tube to ensure uniformity and proper alignment with tube fittings.

  • Assess the ovality (shape) of the tube to avoid any irregularities that may affect the fitting process or compromise the integrity of tube fittings. These considerations are essential for selecting the right tubing to complement tube fittings effectively.

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