When the steel or sample of the spiral pipe equipment is stretched, when the stress exceeds the elastic limit, even if the stress is no longer added, and the steel or the sample continues to undergo significant plastic deformation, the manufacturer of the spiral pipe equipment calls this phenomenon a yield, and The minimum stress value at the time of seizure is the point of compliance.
Submission strength. The yield point of some metal materials is extremely inconspicuous and has difficulty in measurement. Therefore, in order to measure the yield characteristics of the data, the stress at the time when the permanent plastic deformation of the rule is equal to a certain value is called the conditional yield strength or simply the yield strength σ0. .2 .
Yield ratio. The ratio of the yield point of the steel to the tensile strength is called the yield ratio. The higher the yield ratio, the higher the reliability of the structural parts. The general carbon steel yield ratio is 0.6-0.65, and the low alloy structural steel is 0.65-0.75 alloy structural steel is 0.84-0.86.
tensile strength. The maximum stress value reached during the stretching process from the beginning to the onset of cracking. It shows the ability of steel to resist cracking. Corresponding to the tensile strength, there are compressive strength, bending strength, and the like.
Elongation. After the data is broken, the length of the plastic elongation and the length of the original sample are called elongation or elongation.
Hardness. Hardness indicates that the data resists the ability of a hard object to press into its appearance. It is one of the important performance goals of metal materials. Generally, the higher the hardness, the better the wear resistance. Commonly used hardness targets are Brinell hardness, Rockwell hardness, and Vickers hardness. Brinell hardness: press a hardened steel ball of a certain size into the outer surface of the data with a certain load. After a period of time, after loading, the ratio of the load to the area of the indentation is the Brinell hardness value in kilograms/mm2. . Rockwell hardness: When HB>450 or the sample is too small, the Brinell hardness test cannot be used instead of Rockwell hardness measurement. It uses a diamond cone with a apex angle of 120° or a steel ball with a diameter of 1.59 and 3.18 mm. The steel is pressed into the surface of the measured data under a certain load, and the hardness of the data is determined from the depth of the indentation. According to the hardness of the experimental data, there are three different scales to indicate:
HRA: It is the hardness obtained by using 60kg load and diamond cone indenter for the extremely high hardness data.
HRB: It is a steel ball that is hardened with a load of 100 kg and a diameter of 1.58 mm. The hardness is obtained for low hardness data.
HRC: is the hardness obtained by using 150kg load and diamond cone indenter for high hardness data.
Vickers hardness: Pressed into the data surface with a load of 120 kg or less and a diamond square cone presser with a apex angle of 136°, and the load value is divided by the external product of the data indentation pit, which is the Vickers hardness value.
What are the differences in the production process of spiral welded pipes? Straight welded pipes and spiral welded pipes are all kinds of welded steel pipes. They are widely used in the production of national products. Straight welded pipes and spiral welded pipes have many differences due to different production processes. The following is a detailed comment on the difference between straight seam welded pipe and spiral welded pipe.

The production process of straight seam welded pipe is relatively simple. The primary production process includes high-frequency welding straight seam welded pipe and submerged arc welded straight seam welded pipe. The straight seam pipe has high production efficiency, low cost and quick development.

The strength of the spiral welded pipe is generally higher than that of the straight welded pipe. The primary production process is submerged arc welding. The spiral welded pipe can produce welded pipes with different pipe diameters by using blanks of the same width, and can also produce welded pipes with larger diameters by using narrower blanks.

The manufacturer of spiral tube equipment introduces you to the differences in the production process of straight seam welded tubes and spiral welded tubes:

Compared with the straight pipe with the same length, the spiral welded pipe adds 30~100% of the weld length and the production speed is low. Therefore, most of the smaller diameter welded pipes are straight seam welded, and the large diameter welded pipes are mostly spiral welded. In the production of large-diameter self-welding pipes in the industry, the T-welding technology will be used to connect a short straight seam welded pipe to a length that meets the requirements of the project. The probability of defects in the T-weld straight seam welded pipe is also greatly improved, and the T-shape The welding residual stress at the weld is large, and the weld metal is often in a three-way stress condition, adding the possibility of cracking.