Hot-rolled steel pipes are seamless steel pipes made from steel raw materials and rolled above the recrystallization temperature. They are available in large-diameter and small-diameter types. High-temperature rolling refines the grains and eliminates internal defects, improving density and mechanical properties. The outer diameter is typically greater than 32mm, and the wall thickness ranges from 2.5-75mm. Raw materials include carbon structural steel, low-alloy steel, and alloy steel. According to their applications, they can be classified into general steel pipes, low- and medium-pressure boiler tubes, high-pressure boiler tubes, and alloy pipes, and are widely used in fluid transportation, mechanical parts manufacturing, and building structures.
GNEE hot-rolled steel pipe plant equipment includes:
1. Piercing Mill
- Function: Pierces solid round steel billets into hollow tubes. Common types include skew rolling piercing mills and pressure piercing mills.
- Key parameters: Maximum piercing diameter up to Φ250mm (refer to the "Rolling Machinery Design Manual"), elongation coefficient 2.5~4.5.
2. Tube Rolling Mill
- Type: Includes continuous tube rolling mills (such as the PQF three-roll continuous rolling mill) and automatic tube rolling mills (such as Accu-Roll).
- Capacity: The annual output of a single PQF unit is approximately 500,000 tons (data source: technical report of the German SMS Group).
3. Sizing Mill
- Function: Controls the accuracy of the outer diameter of the steel pipe. Typically, three-roll micro-tension sizing is used, with a tolerance range of ±0.5%~1%.
4. Heating Furnace
- Selection: Walking beam furnace is suitable for large-sized billets, with a heating temperature of 1200~1280℃.
5. Straightening Machine
- Parameters: Seven-roll straightener can handle steel pipes with diameters of Φ20~180mm, and a straightening speed of 0.5~2m/s.
6. Automated Control System
- Includes a PLC control module and an online inspection instrument (such as an ultrasonic thickness gauge), with an error detection accuracy of ±0.1mm.
