Inferior stainless steel welded pipes are not only unsatisfactory in use but also have a short service life. However, many customers do not know what kind of stainless steel welded pipe is inferior when purchasing. Today Torch has sorted out some content for you, as long as the stainless steel welded pipe appears as follows One of the five problems is inferior products.
Identify Inferior Stainless Steel Welded Pipes at a Glance
1. Shrinkage
What is a shrinkage cavity, shrinkage cavity is when stainless steel molten steel shrinks in the mold in a liquid state, sometimes due to environmental influences, such as air, temperature, etc., some shrinkage cavities are formed. From a professional point of view, it is called a shrinkage cavity.
2, Transverse Crack
Transverse cracking is easier to understand, that is, transverse cracks have occurred on the surface of stainless steel. Generally, transverse cracks occur during the period of steel ingots, but most of them are shallow in depth.
3. Longitudinal Split
Knowing the horizontal split, then the meaning of the vertical split is obvious. Longitudinal cracks are always desired cracks that appear on the surface of the steel ingot, which generally appears in the upper corners, and the longitudinal cracks appearing on the upper side will be deeper.
4. Scarring
As mentioned above, longitudinal cracks may appear in the upper part or corners of the stainless steel, then sometimes there will be shell makeup or metal splashing of tumor makeup in the lower area, which looks like a layer of the scar. So it’s called scarring. But this kind of problem is rare.
5. Surface Pores
Stomatal is also well understood, that is, many small holes can be seen with the naked eye on the surface of stainless steel. Most of these stomata are very shallow, like transverse cracks.
How to Avoid Choosing Inferior Stainless Steel Welded Pipe
1. Material Composition Analysis:
One of the main indicators of the quality of stainless steel welded pipe is its material composition. High-quality stainless steel should contain certain proportions of chromium, nickel, molybdenum, carbon, and other elements. To verify the composition, a spectrometer can be used or a sample sent to a reputable laboratory for analysis. Comparing the results obtained with the expected values for the selected stainless steel grade will confirm its authenticity.
2. Weld Inspection:
The welding process plays a vital role in the integrity of stainless steel tubing. Carefully inspect welds for any irregularities such as cracks, inclusions or lack of fusion. High-quality pipe usually has smooth and consistent welds, while poor-quality pipe may show signs of poor workmanship. Also, check the welds for discoloration, as discoloration may indicate poor heat treatment or the use of substandard filler materials.
3. Surface Finish and Texture:
True stainless steel welded pipe should have a smooth, uniform surface finish. Run your finger along the surface of the pipe to check for rough patches, bumps or uneven texture. These defects may indicate substandard manufacturing workmanship or the use of low-grade stainless steel.
4. Magnetic:
Stainless steel should generally be non-magnetic, especially commonly used grades such as 304 and 316. If the welded pipe exhibits magnetism, it may contain higher levels of ferrite, indicating lower quality or even plain carbon steel can be used instead of true stainless steel.
5. Corrosion Resistance Test:
Corrosion resistance is one of the main advantages of stainless steel. A small section of welded pipe is tested for corrosion resistance using an etchant appropriate for the stainless steel grade. Observe the reaction for the specified time, if evidence of corrosion is evident, it may indicate the presence of impurities or lower-grade material.
6. Pressure and Load Capacity:
High-quality stainless steel welded pipes should be able to withstand predetermined pressures and loads. Pressure testing is performed on pipe samples to assess their strength and resistance to internal forces. If the pipe cannot meet the required pressure or load capacity, it may be a substandard product, which may bring risks in actual application.
In Conclusion:
Identifying poor-quality welded stainless steel pipe is critical to ensuring the safety, reliability, and longevity of industrial installations and infrastructure. By employing these methods of inspection and testing, consumers and businesses can make informed decisions when purchasing stainless steel welded pipe, ensuring they are getting a high-quality product that meets the standards required for their application. Always source materials from reputable suppliers that guarantee the performance and integrity of stainless steel welded pipes for various industries.