The seamless pipe production process starts with selecting steel billets. The stainless steel billets come in different sizes. Manufacturers choose superior billets so that they can produce high-quality products. Next in the process is to heat the billets to make them malleable. Pipe suppliers use mandrels to pierce the heated billets and create the mother hollow.
Once they create the hollow, they increase the diameter of the pipes depending on the industry the pipes will cater to. Seamless tubes and pipes are produced using two processes – hot rolling and cold drawing.
Some common errors occurring during seamless pipe manufacturing:
Manufacturers use these two methods to produce circular pipes or tubes with different shapes. Even though pipe providers use upgraded tools and follow the steps meticulously, sometimes they come across some errors. Knowing the errors can help seamless pipe suppliers deal with them effectively and prevent them.
Out-of-tolerance diameters:
One of the most common errors occurring during the seamless pipe manufacturing process is the out-of-tolerance diameters. When the molds do not match during cold drawing, it results in an out-of-tolerance diameter.
The same problem can also occur when the mold lacks hardness, or the manufacturers ignore the difference in mold extubation. Sometimes the straightening roller excessively reduces the diameter of the pipes. It is also responsible for out-of-tolerance diameters.
Inclusions:
Many a time, seamless steel pipe suppliers have to scrap their products because of the surface cracks. These surface cracks are the result of inaccurate smelting, heat treatment, and casting processes. If pipe providers cannot find the problem after heat treatment, the inclusions get embedded in the pipes during annealing.
The best way to deal with the problem is to inspect the pipes thoroughly after heat treatment, casting, and smelting. Seamless pipe manufacturers may need to employ multiple inspection methods to identify the issues. When they find inclusions, they can straighten and remove the surface cracks before moving to anneal the pipes and tubes.
Out-of-tolerance wall thickness:
Seamless tubes and pipes generally have thicker walls in comparison with other types of pipes. However, sometimes the wall thickness of the tubes can be out of proportion. The reason behind the error is an improper cold drawing of the tubes. Low wear resistance and mold hardness can also be the reasons behind the issue.
Sometimes pipe fabricators ignore minor changes in the mold size due to wear and tear. As a result, they position the mandrel incorrectly. They may use a shorter and thinner mandrel to pierce the tubes. The result is obvious – out-of-tolerance wall thickness.
If manufacturers want to avoid the situation, they should match the mold and the mandrels correctly during the seamless pipe manufacturing process. They should also check the wall thickness of the steel pipes to ensure the mandrels fit them properly to produce accurate wall thickness.
Uneven wall thickness:
The previous point brings us to the following common error, which is uneven wall thickness. The tube blank can be too small or too large, and the drawing line along with the axis can be inconsistent. Manufacturers can reduce the problems by checking the molds properly. Also, they should adjust the mandrels and check whether they are small or large for the pipes.
Conclusion:
One of the primary concerns of seamless pipe fabricators is the errors in the seamless piping and tubing production process. Even though they use superior materials, sometimes errors occur during the multiple stages of production. Checking the pipes after each step is completed and measuring the diameters, wall thicknesses, etc., of the pipes, is mandatory to reduce errors.
