Complete solution of main hardness index of spiral welded pipe

Spiral welded pipe refers to the steel pipe whose outer diameter and wall thickness ratio is less than 20 as spiral welded pipe. Mainly used for petroleum geological drilling pipes, petrochemical industry cracking pipes, boiler pipes, bearing pipes and high-precision structural pipes for automobiles, tractors, aviation, etc. Then, let’s learn about the main hardness indicators of spiral welded pipes.

Spiral welded pipe is a common product in machining at present. Spiral welded pipe is the most expensive product in steel products. Therefore, the development of spiral welded pipe has attracted the attention of the majority of traders and end users. According to the material of the spiral welded pipe, it can be divided into two types: carbon steel spiral welded pipe and alloy spiral welded pipe.

Carbon steel spiral welded pipe is divided into two categories: 20# and 45#. Carbon steel spiral welded pipe is one of the most widely used spiral welded pipe products at present. Customers are welcome to come to our company to order various carbon steel spiral welded pipe and alloy spiral welded pipe products!

The difference between the spiral welded pipe and the thin-walled steel pipe is that the thickness of the steel pipe wall is distinguished by the unit of measurement. The wall thickness/pipe diameter equal to 0.02 is the watershed between the spiral welded pipe and the thin-walled steel pipe, and the pipe diameter less than 0.02 is the thin-walled steel pipe, and the pipe diameter greater than 0.02 is the thin-walled steel pipe. Spiral welded pipes, generally thin-walled steel pipes are cold-drawn technology, while spiral welded pipes generally use hot-rolled technology. It is generally believed that thin-walled steel pipes are mostly used for pipes. Under pressure, it is used on important piping.

The main hardness index of spiral welded pipe: Vickers hardness method, which overcomes their basic shortcomings, but is not as simple as the Rockwell method. The Vickers method is rarely used in steel pipe standards. It can be used to determine the hardness of thin metal materials and surfaces. It has the main advantages of Brinell method and Rockwell method. Rockwell hardness can be applied to the measurement of soft metal materials to hard metal materials. This makes up for the shortcomings of the Pasteur method. The Brinell hardness in the steel pipe specification is widely used, and the indentation diameter d is used to represent the hardness of the material, which is intuitive. Convenience. Easier than the Pasteur method, the hardness value can be read directly from the dial of the hardness tester. However, due to the small indentation, the hardness value is not as accurate as the Brinell method.

Introduction of Vickers hardness test of spiral welded pipe: after the specified holding time, the test force is eliminated, and the length of the double diagonal line of the indentation is measured. The Vickers hardness test is also an indentation test method. A regular quadrangular pyramid diamond indenter (f ) with a relative face angle of 1360 is used to indent into the test surface. The Vickers hardness value is the quotient of the test force divided by the indentation surface area, and its calculation formula is In, HV--Vickers hardness symbol, n/mm2 (MPa); F--test force, n; d-- arithmetic mean of indentation double diagonal, mm. Vickers hardness includes 5 (49.03), (10) (98.07), (20) (196.1), (30) (294.2), (50) (490.3), (100) (980.7) and other 6-level hardness test force .

The range of the spiral welded pipe is 5~1000HV. According to the test method and scope of application, hardness is divided into Brinell hardness, Rockwell hardness, Vickers hardness, Shore hardness, microhardness, high temperature hardness, etc. Hardness refers to the resistance of a metal material to a hard object sinking into the surface, called hardness.

The above is the complete solution of the main hardness indicators of the spiral welded pipe. If you want to know more, please feel free to contact us!