There is a situation in the market where 304 or ordinary stainless steel is used to imitate 347 stainless steel pipes. Users can effectively distinguish the authenticity through two methods: material testing and interpretation of the quality guarantee certificate.
In terms of material testing, the most reliable method is to use a spectrometer to detect the chemical composition. The key element content range for 347 stainless steel tubes is as follows: chromium (Cr) 17.0% - 19.0%, nickel (Ni) 9.0% - 13.0%, and niobium (Nb) is 10 times the carbon content and does not exceed 1.10%. If the niobium element content is low or not detected, it may be a counterfeit of 304 or 304L. Additionally, an intergranular corrosion test can be used as an auxiliary judgment - 347 stainless steel tubes still maintain good corrosion resistance after welding or sensitization treatment, while ordinary 304 tubes will show a significant intergranular corrosion tendency under the same conditions.
Interpreting the warranty certificate is another important method for identifying authenticity. A genuine warranty certificate should contain the following information: the manufacturer's name, the applicable standard (such as ASTM A312 or GB/T 14976), the furnace batch number, the measured values of chemical composition (pay special attention to whether the niobium content meets the standard), the measured values of mechanical properties (yield strength, tensile strength, elongation rate, etc.) and the official seal. Users should verify whether the measured data in the warranty certificate meets the standard requirements and pay attention to whether the furnace batch number in the warranty certificate is consistent with that on the actual product. It is recommended to request the supplier to provide the original factory warranty certificate instead of a self-printed copy.
For large-scale purchases or critical applications, it is recommended to entrust a qualified third-party testing institution to conduct re-inspection to ensure the authenticity and reliability of the materials.
Jiangsu Cunrui Metal Products Co., Ltd. The 347 stainless steel pipes we supply are all of genuine quality. We will provide the original factory warranty certificate with the goods, and we also support customers in having the products re-inspected and verified by a third-party testing institution.
If you need any assistance, please feel free to contact our company at any time. We will be more than happy to offer you high-quality products and services.