Description
Cold-deformed (cold-rolled) seamless pipes are products of the highest quality, designed for critical applications where reliability, geometric precision, and strength are crucial. They are manufactured without a weld seam using the cold plastic deformation method.
Manufacturing Technology

The initial workpiece for production is hot-rolled seamless pipes. The process of transforming them into cold-deformed pipes includes several stages:
1.    Workpiece Preparation: The hot-rolled pipe is cleaned of scale (e.g., by pickling) and pickled to obtain a clean surface.
2.    Cold Deformation: The main stage, which can be performed in three ways:
o    Cold Rolling in rolls on cold pilger mills (CPM-32, -55, -90, etc.). This method is the most common for serial production.
o    Cold Drawing through a die on drawing mills. Allows for pipes with particularly high precision and surface quality.
o    Combined Method, combining rolling and drawing to achieve optimal results.
3.    Heat Treatment (Tempering/Annealing): After cold deformation, the metal becomes excessively hard and brittle (strain hardening). To relieve internal stresses and restore plasticity, pipes are necessarily subjected to heat treatment in furnaces.
4.    Straightening and Calibration: The final operation to ensure perfect geometry and precise dimensions.
The State Standard establishes the assortment of seamless cold-deformed pipes with an outer diameter from 5 mm to 250 mm (according to GOST 8734-75).

Classification by Wall Thickness
Steel cold-deformed pipes are divided into four main groups:
•    Extra-thin-walled
•    Thin-walled
•    Thick-walled
•    Extra-thick-walled

The smaller the wall thickness, the lower the weight of the final structure, which is critically important for industries such as aviation and precision engineering.
Key Advantages
•    High Strength and Reliability: The absence of a weld seam – the weakest point of any pipe – makes them exceptionally resistant to high pressure and shock loads.
•    Ideal Geometry and Smoothness: Cold deformation allows for minimal tolerances in diameter and wall thickness, as well as an almost perfect surface.
•    Versatility and Corrosion Resistance: Suitable for transporting aggressive media, gases, and liquids under high pressure. Ensure complete tightness.
•    Resistance to Loads and Temperatures: Maintain integrity and mechanical properties under significant temperature fluctuations and mechanical stress.
•    Wide Assortment: Possibility to produce both standard sizes and products according to customer's individual technical requirements.

Areas of Application
Thanks to their excellent properties, cold-deformed seamless pipes are used in the most critical industries:
•    Mechanical Engineering: Production of hydraulic and pneumatic cylinders, piston rods, shafts, fuel system components.
•    Aviation and Aerospace Industry: Structural elements and high-pressure systems.
•    Oil & Gas and Chemical Industry: Pipelines for aggressive media, equipment for high pressures.
•    Power Engineering: Heat exchanger tubes, high-pressure boiler elements.
•    Automotive Industry: Suspension components, transmission elements.

GOST Standards and Normative Documentation
The quality and supply of seamless cold-deformed pipes in Russia and CIS countries are regulated by the following main standards:
•    GOST 8733-74 – Main standard. "Steel seamless cold-deformed pipes. Technical specifications." Defines steel grades, mechanical properties, chemical composition, types of heat treatment, and control methods.
•    GOST 8734-75 – "Steel seamless cold-deformed pipes. Assortment." Establishes the exact list of dimensions: outer diameters (5-250 mm), wall thicknesses, lengths, and theoretical mass.
•    GOST 9940-81 – "Seamless hot-deformed and cold-deformed pipes made of corrosion-resistant steel." Applies to stainless steel pipes.
•    GOST 9941-81 – "Seamless hot-deformed and cold-deformed pipes made of heat-resistant steel."