We offer a comprehensive range of precision metal processing equipment, including straightening, cold drawing, pointing, chamfering, cutting, thread rolling machines, and drawing dies, tailored for tube, bar, and wire materials across diverse industries.
FangRong's Expansion Drawing Machine is designed for increasing the outside diameter of tubes while keeping the tube wall under controlled deformation. The hydraulic system drives a tapered mandrel through the tube, while segmented dies guide the material outward to the required diameter. This makes the process suitable when a larger tube diameter is required without relying on conventional forming methods that may cause excessive wall variation.
During tube expansion, increasing the outside diameter is only part of the requirement. If the material is expanded too aggressively, wall thickness can become uneven or the tube may develop cracks. FangRong's hydraulic system uses controlled pressure and staged expansion sequences to keep the deformation within the selected process range. Depending on the tube material and dimensions, expansion ratios of up to 30% in one pass are possible.
The machine can process copper, aluminum, carbon steel and stainless steel tubes, with tube outside diameters from approximately 10 to 200mm. Custom mandrel designs are available for different tube dimensions and material grades, since mandrel geometry has a direct effect on expansion load, dimensional accuracy and wall-thickness control.
FangRong's hydraulic expansion drawing machines cover 10T to 500T of pulling force, with main cylinder diameters from φ125mm to φ630mm and effective expansion strokes up to 10m. For example, the FR-100T uses a φ250mm main cylinder and 100T drawing force with two 55kW pump motors. At the higher end, the FR-500T provides 500T force through a φ630mm cylinder and uses two 75kW fixed-displacement pumps with two 110kW motors.
Model selection depends on more than the target tube diameter. Starting wall thickness, material strength, required expansion ratio, tube length and the number of expansion passes all affect the required machine force and tooling configuration. For smaller or lighter tubes, excessive machine capacity may add cost without improving the finished product.
Expansion loads can change as the tube enters different sections of the mandrel and die. Real-time pressure monitoring helps operators identify abnormal resistance during the process, while step-by-step expansion sequences reduce sudden loading on the tube. This is particularly important for stainless steel and other higher-strength materials, where an unsuitable expansion rate can increase the risk of cracking.
Typical applications include air-conditioning fittings, automotive exhaust pipes, heat exchanger tubes and plumbing connectors. After expansion, the machine can be connected with FangRong's Straightening Machine and Cutting Machine to continue dimensional correction and length processing without adding unnecessary material handling between operations.
The Automatic Expansion Drawing Machine is used when a pipe needs a larger or more accurate internal diameter without heating the material. A hydraulic cylinder drives an expansion mandrel through the bore, providing controlled radial deformation to correct internal dimensions and ovality. The FR-10T to FR-500T range covers expansion forces of 10–500 tons with strokes up to 10 m, while multi-pump hydraulic systems match power output to different pipe sizes and loads. It is suitable for carbon steel, alloy steel, stainless steel, and specialty metal pipes, including large-diameter precision pipes, deformed sections, and pipe ends prepared for joining.
