Stainless steel seamless pipe is a long steel strip with a hollow cross-section and no seams around it. The thicker the wall thickness of the product, the more economical and practical it is. The thinner the wall thickness, the higher the processing cost.
The process of this product determines its limited performance.
Generally, seamless steel tubes have low precision: uneven wall thickness, low brightness of the inner and outer surfaces of the pipe, high cost of cutting, and pitting and black spots on the inner and outer surfaces are difficult to remove; its detection and shaping must be processed offline. Therefore, it has demonstrated its superiority in high pressure, high strength, and mechanical structure materials.
What are the common quality problems of stainless steel seamless pipes?
As an important industrial material, stainless steel seamless pipes are widely used in petroleum, chemical, electric power, medicine and other fields. However, during the production and use process, stainless steel seamless pipes may encounter some common quality problems, which not only affect the performance and service life of the pipes, but also may pose a potential threat to production and safety.
The following are common quality problems of stainless steel seamless pipes and their causes:
1. Chemical composition does not meet the standards
The chemical composition of stainless steel seamless pipe is the key factor determining its performance. If the chemical composition does not meet the standard, such as the content of carbon, chromium, nickel and other elements do not meet the standard requirements, the corrosion resistance and mechanical properties of the pipeline will be affected. The reasons for this problem may be poor quality of raw materials, improper control of smelting process, etc.
2. Dimensional accuracy does not meet requirements
The dimensional accuracy of stainless steel seamless pipes includes outer diameter, wall thickness, length, etc. If the dimensional accuracy does not meet the requirements, it will affect the installation, connection and use of the pipeline. The reasons for this problem may be improper production process control, insufficient equipment accuracy, etc.
3. Poor surface quality
The surface quality of stainless steel seamless pipes directly affects their appearance and performance. Common surface quality problems include cracks, pits, scratches, rust, etc. These problems not only affect the aesthetics of the pipeline, but may also reduce its corrosion resistance and mechanical properties. The cause of this problem may be improper operation of rolling, pickling, polishing, etc.
4. Internal defects
The internal defects of stainless steel seamless pipes mainly include inclusions, bubbles, cracks, etc. These defects can reduce the strength and toughness of the pipeline and increase the risk of pipeline rupture. The cause of this problem may be improper control during the smelting and rolling process, or quality problems of the raw materials themselves.
5. Performance not up to standard
The performance of stainless steel seamless pipes includes corrosion resistance, mechanical properties, high temperature performance, etc. If the performance does not meet the standards, it will affect the use effect and life of the pipe. The cause of this problem may be that the chemical composition, heat treatment process, etc. do not meet the requirements.
6. Problems during packaging and transportation
During packaging and transportation, stainless steel seamless pipes may be damaged by extrusion, collision, etc., resulting in pipe deformation, scratches and other problems. In addition, if the packaging materials do not meet the requirements or the packaging method is improper, the pipeline may be damaged during transportation.
How to detect the quality of stainless steel seamless pipes？
The quality identification of stainless steel seamless pipes involves many aspects, from appearance inspection to chemical composition analysis to mechanical property inspection, each step is crucial. The following will introduce in detail how to identify the quality of stainless steel seamless pipes in all aspects.
1. First of all, appearance inspection is the first step in quality identification of stainless steel seamless pipes. The surface should be carefully checked to see if it is smooth and free of defects such as cracks, folds, interlayers and bubbles. The surface should be clean and flat, without scratches, indentations, oil stains and other defects. In addition, the dimensions such as outer diameter, wall thickness and length should also comply with relevant standards.
2. Secondly, chemical composition analysis is an important means to identify the quality of stainless steel seamless pipes. Commonly used chemical composition detection methods include spectral analysis, electrochemical analysis, flame atomic absorption spectrometry and X-ray fluorescence analysis, etc. These methods can accurately detect the content of various elements in stainless steel seamless pipes, so as to determine whether they meet the requirements of product standards.
3. Again, mechanical properties testing is also an indispensable link. Tensile strength, bending performance and hardness are important mechanical properties of stainless steel seamless pipes. Tensile strength can be tested by tensile testing, flexural properties can be assessed by three-point bending tests, and hardness can be tested using methods such as Brinell hardness, Vickers hardness, and Rockwell hardness. These tests can ensure that the stainless steel seamless pipe has sufficient strength and plasticity to meet the design requirements.
4. In addition to the basic inspection methods mentioned above, there are also some specific identification methods. For example, the material and quality of stainless steel seamless pipes can be roughly judged through methods such as potency testing, magnetic adsorption properties testing, knocking testing, salt water testing and white rice vinegar testing. These methods are simple and quick to operate, but the results can only be roughly known and cannot quantitatively analyze and measure the composition of the material.
5. In addition, the acceptance criteria for stainless steel seamless pipes should also include pressure testing. By conducting hydraulic or pneumatic pressure tests on stainless steel seamless pipes, their pressure resistance can be verified to ensure that the product will not leak or rupture under the design pressure.
6. Then, in order to more accurately detect the quality of stainless steel seamless pipes, some testing equipment can also be used, such as infrared CS instrument, direct reading spectrometer, etc. These devices can analyze the content of specific elements in stainless steel seamless pipes, or check their geometric dimensions and shapes.
Read more：Advantages and Disadvantages of Stainless Steel Seamless Pipes
