Difference Between Cold-drawn & Hot-rolled Seamless Steel Pipe

There are obvious differences between cold-drawn seamless steel pipe and hot-rolled seamless steel pipe in manufacturing process, materials and performance, application fields, appearance and dimensional characteristics, manufacturing cost and difficulty. When choosing to use seamless steel pipes, you should choose according to specific needs and application scenarios. In practical applications, cold-drawn seamless steel pipes perform particularly well under extreme working conditions due to their high strength and high precision, such as deep-sea oil and gas exploration, aerospace and other fields, and their long-term stability and corrosion resistance have become irreplaceable advantages. However, this also means that under normal working conditions, there may be problems of over-design leading to rising costs.

In contrast, although the performance of hot-rolled seamless steel pipes is slightly inferior, its good toughness and low manufacturing cost make it occupy an important position in many infrastructure and industrial applications. Especially in scenarios that require large quantities and rapid installation, such as urban water supply and drainage systems, HVAC projects, etc., hot-rolled seamless steel pipes are the first choice because of their economy and easy processing. The following is a detailed analysis of the difference between cold-drawn seamless steel pipes and hot-rolled seamless steel pipes:

Differences in manufacturing processes

1. Cold-drawn seamless steel pipes

Made through multiple drawing and annealing treatments. The specific process is to pass the steel billet through a hole with a certain specification of round holes, and gradually reduce the pipe diameter and increase the wall thickness through multiple drawing.

2. Hot-rolled seamless steel pipes

Made through a rolling process at high temperature. The specific process is to heat the steel billet in a heating furnace to above the recrystallization temperature, and then through continuous rolling of multiple rollers, the steel billet is gradually deformed and thinned, and finally a seamless steel pipe of the required specifications is formed.

Differences in appearance and dimensional characteristics

1. Cold-drawn seamless steel pipes

Generally, the diameter is small, mostly below 127mm, the outer diameter accuracy is very high, the length is usually shorter than that of hot-rolled seamless steel pipes, and the wall thickness is more uniform.

2. Hot-rolled seamless steel pipes

The outer diameter is generally greater than 32mm, the wall thickness ranges from 2.5-75mm, the outer diameter accuracy is relatively low, and the surface may be rough.

Differences in materials and properties

1. Cold-drawn seamless steel pipe

Cold-drawn seamless steel pipes are generally made of high-carbon steel or alloy steel, with high strength, hardness and fatigue resistance, but relatively poor toughness.

2. Hot-rolled seamless steel pipes

Hot-rolled seamless steel pipes are made of low-carbon steel or low-alloy steel, with low strength and hardness, but good toughness, and are easy to process and weld.

Differences in manufacturing cost and difficulty

1. Cold-drawn seamless steel pipe

The manufacturing process is complex, requiring multiple drawing and annealing treatments, long production cycle, low output, and therefore high manufacturing cost.

2. Hot-rolled seamless steel pipe

The manufacturing process is relatively simple, with a short production cycle and high output, so the manufacturing cost is relatively low.

Differences in application areas

1. Cold-drawn seamless steel pipe

Cold-drawn seamless steel pipes are mainly used to manufacture pipelines and mechanical parts for high-precision, high-pressure, high-temperature and special medium transportation, such as automobile drive shafts, turbine engines, high-pressure vessels, etc.

2. Hot-rolled seamless steel pipe

Hot-rolled seamless steel pipe is more used to manufacture structural parts and fluid delivery pipelines that do not require high strength but require good toughness, such as building structures, boilers, water and gas pipelines, etc.

Summary

There are significant differences between cold-drawn seamless steel pipes and hot-rolled seamless steel pipes in terms of manufacturing process, material properties, application areas, appearance dimensions and manufacturing costs. Cold-drawn steel pipes have high strength but poor toughness and are suitable for high-precision and high-pressure occasions; hot-rolled steel pipes have good toughness but low strength and are mostly used for structural parts and fluid delivery. The choice should be made according to specific needs. With the advancement of science and technology and the innovation of technology, the seamless steel pipe industry is also developing continuously. The introduction of new materials, such as stainless steel and duplex steel, has further enriched the types and performance of seamless steel pipes, enabling them to adapt to more diversified application needs. At the same time, the establishment of intelligent production lines not only improves production efficiency and product quality, but also reduces energy consumption and emissions, and promotes the sustainable development of the seamless steel pipe industry.