The difference between hot rolled cold seam steel pipe and hot rolled seamless steel pipe

1.Hot-rolled seamless steel pipes are divided into general steel pipes, low and medium pressure boiler steel pipes, high-pressure boiler steel pipes, alloy steel pipes, stainless steel pipes, petroleum cracking pipes, geological steel pipes and other steel pipes.

2.In addition to general steel pipes, low and medium pressure boiler steel pipes, high-pressure boiler steel pipes, alloy steel pipes, stainless steel pipes, petroleum cracking pipes and other steel pipes, cold-rolled seamless steel pipes also include carbon thin-walled steel pipes, alloy thin-walled steel pipes, stainless steel thin-walled steel pipes, and special-shaped steel pipes. The outer diameter of the hot-rolled seamless pipe is generally greater than 32mm, the wall thickness, the diameter of the cold-rolled seamless steel pipe can be up to 6mm, the wall thickness can be reached, the outer diameter of the thin-walled pipe can be up to 5mm, the wall thickness is less than, and the cold-rolled has higher dimensional accuracy than hot-rolled.

There are certain differences between seamless steel pipe continuous rolling and hot rolling in terms of production efficiency, quality control, process requirements, etc.

1.Production efficiency: The seamless steel pipe continuous rolling process does not require Zao Zhaoju to manufacture blanks according to the size of the finished product, which greatly saves production time and cost, and the production speed is higher. Hot rolling, on the other hand, requires the billet to be continuously heated, rolled and cooled, and circulated, at a relatively slow speed.

2.Quality control: The seamless steel tube continuous rolling process allows for better control of dimensional accuracy and mechanical properties, as its production process is more sophisticated and refined.

However, hot rolling is susceptible to temperature changes and various factors in the rolling process, and the mechanical properties and dimensional accuracy of the product are relatively poor.

3.Process requirements: Seamless steel pipe continuous rolling requires the use of high-precision equipment and processes for production, and the requirements are relatively high. Hot rolling, on the other hand, is relatively simple and has low requirements for equipment and stool technology.

1. Different classifications:

Hot-rolled seamless pipes are divided into general steel pipes, low and medium pressure boiler steel pipes, high-pressure boiler steel pipes, alloy steel pipes, stainless steel pipes, petroleum cracking pipes, geological steel pipes and other steel pipes.

In addition to general steel pipes, low and medium pressure boiler steel pipes, high-pressure boiler steel pipes, alloy steel pipes, stainless steel pipes, petroleum cracking pipes and other steel pipes, cold-rolled seamless free steel pipes also include carbon thin-walled steel pipes, alloy thin-walled steel pipes, stainless steel thin-walled steel pipes, and special-shaped steel pipes.

2. The process flow is different

Hot rolled seamless steel tube round tube billet Heating Perforation Three-high skew rolling, continuous rolling or extrusion Tube removal Sizing Cooling Billet straightening Hydrostatic test Marking Warehousing.

Seamless steel tube round tube billet heating, perforation, heading, annealing, pickling, oiling, multi-pass cold drawing, billet tube, heat treatment, straightening, hydrostatic test, marking, warehousing.

After hot rolling, the non-metallic inclusions (mainly sulfides and oxides, as well as silicates) inside the steel are pressed into thin sheets, resulting in delamination (interlayering). Delamination greatly deteriorates the tensile properties of the steel along the thickness direction, and interlaminar tearing is possible when the weld shrinks. The local strain induced by weld shrinkage often reaches several times of the yield point strain, which is much larger than the strain caused by the load.

Steel pipes are the building materials we often use in our daily life, among which the more common ones are hot-rolled steel pipes and cold-rolled steel pipes. What is the difference between these two kinds of steel pipes?

First of all, the manufacturing process of hot-rolled steel pipe and cold-rolled steel pipe is different. The hot-rolled steel pipe is formed by pressing the billet hot roll at high temperature, at this time, the steel is more flexible due to the high temperature, and then combined with the strong extrusion of the pressure roller, a steel pipe with a smooth appearance and rough internal particles is formed. The cold-rolled steel pipe is made by rolling the steel at a relatively low temperature and surface treatment, in this manufacturing process, the surface of the steel pipe is relatively smooth, showing a hollow feeling, and it is more convenient and beautiful to use.

Secondly, the performance of hot-rolled steel pipes and cold-rolled steel pipes is also different. Because the internal particles of hot-rolled steel pipes are relatively coarse, and there are many impurities inside, they are not suitable for use in the field of fine manufacturing. Cold-rolled steel pipes, on the other hand, have a smooth surface and a compact internal structure, so they perform better and are more decorative when used in fine manufacturing fields.

In general, although hot-rolled steel pipes and cold-rolled steel pipes are both steel materials, there are great differences in manufacturing processes and properties, and they should be selected and used according to specific application scenarios.