Description
Hot-Deformed Seamless Pipes are monolithic steel pipes manufactured by hot rolling without a weld seam. They are distinguished by high strength and reliability, making them indispensable for operation under high pressure and in extreme conditions.
Production Technology
The manufacturing process includes several key stages:
1.    Workpiece Preparation: A steel ingot or round billet is used.
2.    Heating: The workpiece is heated in a furnace to a temperature of 1100-1300°C to impart plasticity to the metal.
3.    Piercing: On a piercing mill, a hole is created in the heated workpiece, forming a hollow shell.
4.    Rolling: The shell is sequentially processed on a pilger or automatic mill to achieve the required diameter and wall thickness.
5.    Calibration and Cooling: The pipe undergoes final calibration, cooling, and straightening.

Characteristics and Assortment
•    Size Range: Outer diameter from 25 to 550 mm and more
•    Wall Thickness: from 2.5 to 75 mm
•    Length: measured (6-12 m) and non-measured
•    Accuracy Classes: increased and ordinary

Advantages
•    High Strength due to monolithic structure
•    Resistance to High Pressures and Temperatures
•    Reliability in extreme operating conditions
•    Wide Range of Sizes
•    Cost-Effectiveness for large diameters

Areas of Application
•    Oil & Gas Industry: main pipelines, casing columns
•    Power Engineering: steam lines, high-pressure pipelines
•    Chemical Industry: transportation of aggressive media
•    Construction: load-bearing structures, supports
•    Mechanical Engineering: shafts, cylinders, equipment components

Normative Documentation (GOST Standards)
Main standards regulating the production of hot-deformed pipes:
GOST 8732-78 – "Steel seamless hot-deformed pipes. Assortment"
•    Establishes size ranges, theoretical mass
•    Defines tolerances for diameter and wall thickness
•    Regulates requirements for curvature
GOST 8731-74 – "Steel seamless hot-deformed pipes. Technical specifications"
•    Defines steel grades and mechanical properties
•    Establishes test methods and quality control
•    Regulates acceptance rules and marking
Additional Standards:
•    GOST 9940-81 – for pipes made of corrosion-resistant steel
•    GOST 9941-81 – for pipes made of heat-resistant steel