Plastic Forming Process

1. Hydraulic bulging process

Using a straight pipe billet with the same diameter as the titanium tee, synchronous pressure is applied to both ends of the billet through a hydraulic press to drive the metal to flow towards the mold branch pipe direction under high internal liquid pressure. This process requires the use of balanced convex molds to support the forming of branch pipes, and is suitable for materials such as carbon steel, stainless steel, and titanium. It can achieve uniform wall thickness of branch pipes and high efficiency.

2. Hot pressing forming process

Flatten the billet with a diameter greater than the tee and heat it by opening holes. Use radial compression to promote the flow of metal towards the branch pipe direction, and stretch it through the mold to form the branch pipe. This process has low requirements for equipment tonnage and is suitable for materials with poor high-temperature plasticity such as titanium, but requires precise control of heating temperature and deformation rate.

3. Packing extrusion forming

Fill the straight pipe blank with incompressible medium, and use bidirectional top rod extrusion to synchronize the metal and filler to extrude the branch pipe from the radial hole of the mold. This method can avoid mechanical scratches on the inner wall, and the extrusion height can reach 2-3 times the diameter of the pipe, making it suitable for scenarios with high requirements for inner wall quality.

machining process

1. End reduction method

Using a billet with a diameter 15% -30% larger than the finished product, the two ends are locally heated to form a middle protrusion, and then the protruding part is perforated and flanged to form. Suitable for DN50-DN600 large-sized titanium tees, but with complex processes, low yield, and strict monitoring of wall thickness distribution.

2. Machine addition method

Directly cutting, forging, and machining bars or plates, forming them through processes such as turning and drilling. Suitable for small batches or special size titanium tees, with low material utilization but high dimensional accuracy, commonly used for small pipe fittings below DN25.

procedure

1. Equal diameter welding process

After the main pipe is drilled, a saddle shaped groove design is adopted, and the welding between the branch pipe and the main pipe is completed using flux cored wire CO ₂ gas shielded welding. It is necessary to control the swing amplitude of the welding gun and the length of the repeated weld bead, with a focus on dealing with the triangular empty welding area at the intersection of the belly weld seam, to ensure the uniformity and compressive strength of the weld seam.

Process selection criteria

1. Material characteristics: Titanium has poor room temperature plasticity, and for specifications above DN50, hot pressing or end reduction methods are commonly used; Small size products can be selected through cold extrusion or machining.

2. Specification requirements: Hydraulic bulging is suitable for mass production of standard parts, and welding methods are suitable for irregular or customized needs.

3. Quality level: Plastic forming technology is preferred for high-pressure scenarios, while welding or machining solutions can be considered for low-pressure scenarios.

Key points of quality control

Material pretreatment: It is necessary to strictly test the chemical composition and corrosion resistance of titanium tubes;

Heat treatment: eliminate residual stress after forming and improve structural strength;

Non destructive testing: Penetrant or radiographic testing of welds and formed parts.