The butt welding cross is a steel pipe fitting formed by hot pressing or forging. Its connection form is to directly butt weld the cross and the steel pipe. The main manufacturing standards of the butt welding cross are generally GB/T12459, GB/T13401, ASME B16.9, SH3408, SH3409, HG/T21635, HG/T21631, SY/T0510. Butt-welding four-way has an equal diameter and different diameters. The pipe ends of equal-diameter four-way are the same size.
The butt welding cross is a kind of pipe fitting used in the branch of the pipeline. For the use of seamless pipes to manufacture butt-welded crosses, there are currently two commonly used processes: hydraulic bulging and hot pressing.
Hydraulic bulging The hydraulic bulging of the butt-welding cross is a forming process that expands the branch pipe through the axial compensation of the metal material. The process is to use a special hydraulic machine to inject liquid into the tube blank with the same diameter as the butt-welding cross and squeeze the tube blank through the synchronous centering movement of the two horizontal side cylinders of the hydraulic machine. After the tube blank is squeezed, the volume becomes smaller, and the tube blank pressure of the liquid in the billet increases as the volume of the billet decreases. When the pressure required for the expansion of the butt-welded four-way branch pipe is reached, the metal material flows along the inner cavity of the mold under the dual action of the side cylinder and the liquid pressure in the billet. Expand the branch pipe.
The hydraulic bulging process of the butt-welding cross can be formed at one time, and the production efficiency is high; the wall thickness of the main pipe and the shoulder of the butt-welding cross are both increased. Due to the large tonnage of equipment required for the hydraulic bulging process of seamless butt-welding crosses, it is currently mainly used in the manufacture of standard wall thickness crosses less than DN400 in China. Its suitable forming materials are low-carbon steel, low-alloy steel, and stainless steel with relatively low cold hardening tendency, including some non-ferrous metal materials, such as copper, aluminum, titanium, etc.
Hot press forming Butt-welding cross hot-press forming is to flatten the tube blank larger than the diameter of the butt-welding cross to about the size of the diameter of the butt-welding cross, and open a hole at the position of the stretched branch pipe; the tube blank is heated and placed into the forming die, and put the punching die of the stretching branch pipe in the tube blank; under the action of pressure, the tube blank is radially compressed, and the metal flows in the direction of the branch pipe during the radial compression process and forms the branch pipe under the stretching of the die.
The whole process is formed by the radial compression of the tube blank and the stretching process of the branch pipe. Different from the hydraulic bulging butt welding cross, the metal of the hot pressing butt welding cross branch is compensated by the radial movement of the tube blank, so it is also called the radial compensation process.
Due to the use of heated and pressed butt-welded four-way, the tonnage of equipment required for material forming is reduced. The hot-pressed butt-welded cross has wide adaptability to materials, and is suitable for low-carbon steel, alloy steel, and stainless steel; especially for crosses with large diameters and thicker pipe walls, this forming process is usually used.
1. According to the material, it is divided into carbon steel, cast steel, alloy steel, stainless steel, copper, aluminum alloy, plastic, argon, ppc, etc.
2. According to the production method, it can be divided into the top system, pressing, forging, casting and so on.
3. According to the manufacturing standard, it can be divided into national standard, electric standard, water standard, American standard, German standard, Japanese standard, Russian standard and so on.
