Familiarity with Mannesmann's tube

لوله مانیسمان چیست ؟

This type of pipe was first used by a German engineer named Manisman and was known by this name in Iran. As mentioned above, the seamlessness of Manisman pipes sets them apart from other types of pipes. The weld line in seamed pipes, even under ideal conditions for the welding process, can act as the starting point for cracking and growth, that's why this line has less strength than other parts of the pipe and works weaker. However, Manisman pipe does not have any welding lines or other connections and the pipe body has a uniform structure. As a result, it has higher quality in terms of mechanical strength, corrosion resistance, resistance to heat and high pressures, and it will work more successfully for parts of the industry that require high precision in these features. In general, in the steel industry, pipes are produced in two forms, seamed and seamless. Seamless pipes are called Manisman. The difference between this type of pipe and seamed pipes is that due to not having any seams, its strength is very high. This is while the seamed pipes, no matter how carefully and obsessively they are welded, there is still a possibility for them to crack.

Each factory produces Manisman pipes with a special standard and certificate. Also, the price of the pipe depends on various factors and it is possible that each factory offers a different price in the market. In general, for Mannheim or seamless pipe, there are the following two standards:

Steel pipes with ASME B36.10 standard
Steel pipes with ASME B36 standard. 19

Each of these standards consider a specific diameter, thickness and length for seamless pipes. Therefore, any factory that claims to produce its products according to one of these standards must have acted according to the same criteria.

Manisman pipe is a type of seamless pipe, which, due to the lack of welding, is widely used in parts of the industry where the seamed pipe cannot be answered. These pipes are produced in different types and sizes, of course, the main reason for the difference in the price of each is the same difference in their thickness and size.

مشخصات لوله‌های مانیسمان

Currently, Manisman pipes are procured from domestic and foreign factories inside the country. But they all have the same technical specifications that use ASME B36.10 construction standard for steel pipes and ASME B36.19 construction standard for steel pipes. According to these standards, a range is defined for each of the features and specifications of Manisman pipes, which the final product must comply with. One of these characteristics is the working pressure of the pipe. The working pressure of Manisman pipes is defined according to its size, thickness and working temperature. But considering that at a certain temperature and size, this pressure is the same for all pipes, this characteristic can be checked. For Manisman pipes with a thickness of 1 to 10 inches, and at different temperatures, the amount of this working pressure is given in the relevant standard tables.

Another characteristic of Manisman pipes is its thickness or in technical terms, its grade. Thicknesses are also produced based on different standards. Categories 20, 40 and 80 are the most used thicknesses. Category 20 is also called light pipe. Category 80, which has higher strength, is used in high-pressure and corrosive conditions and is considered one of the heavy pipes. These pipes are produced from 1/8 inch to 26 inch. In almost all cases of the industry, sizes above 26 inches are usually used to transfer long and low-pressure lines, and in these cases there is no significant difference in properties between seamed and seamless pipe. For this reason, it is preferred to use a seamed pipe with a lower price, and as a result, producing a pipe with a size larger than 26 inches will not be economical.

The international standards of Manisman pipes are: ASTM – JIS – DIN