How to distinguish between good and bad 304 stainless steel tubes?

When we use 304 stainless steel tube, sometimes we will find that the surface brightness is not enough, which will not only affect the appearance of 304 stainless steel tube aesthetics, the same can affect its use effect, about the factors affecting the surface brightness of 304 stainless steel tube are as follows.
1. The oil content in the emulsion is too high, the emulsion used in the cold rolling mill is composed of water, emulsifier and oil, the emulsion has both cooling and smooth effect, and 304 stainless steel seamless tube at high temperature will crack into carbon, if these carbon can not be removed in time, thus the oil content in the emulsion is one of the important elements affecting the quality of 304 stainless steel tube.
2. Maintenance cover wall attached to many carbon black, because the emulsion contains a high amount of oil, after the hooded furnace annealing will occur after the carbon phenomenon, so the carbon in the maintenance cover on the inner wall of the accumulation, and with the annealing furnace times increase, carbon black add, if not removed in real time, inevitably, carbon black and will be scattered to other steel coil, after processing, so that carbon attached to the 304 stainless steel pipe with the exterior.
3. HNX annealing furnace recovery function is poor, because HNX annealing furnace in the maintenance of gas Hugh blowing range of only about 20-25 cubic meters (norm) / h, so, in the heating stainless steel tube manufacturer process, gasification of the oil is often difficult to blow net, to the outer ring of the steel coil is still early black band.
In the application of stainless steel tube, 304 stainless steel is one of the most common raw materials, but there are many people do not know how to select 304 stainless steel tube, so how to distinguish the advantages and disadvantages of 304 stainless steel tube?

Stainless steel tube material is the basis for determining the quality of stainless steel tube. Bewell® 316 stainless steel tube has the best corrosion resistance and oxidation resistance. 316 stainless steel tube has the highest price. 304 stainless steel tube is relatively poor, 304 stainless steel tube is slightly cheaper. 201 stainless steel tube material is slightly worse than 304 stainless steel tube, 201 price is also the lowest. The material of stainless steel tube is difficult to distinguish with the naked eye. So, how do we identify the material of stainless steel pipe? The following methods can be used.

Magnetic test: 
316 stainless steel tube and 304 stainless steel tube magnetic low, 201 stainless steel tube magnetic strong, you can test these magnets, but the accuracy is not high, not recommended for everyone to use!

Nitric acid point test: 
Through the nitric acid point test to test the corrosion resistance of the substrate, is the most intuitive test method for stainless steel piping. In general, good 304 stainless steel pipes will only be slightly corroded during the test, with the lowest corrosion resistance and oxidation resistance. Stainless steel piping will have visible signs of corrosion.

Stainless steel measuring solution: 
Also known as stainless steel tube testing potion. First, ensure that the surface of the 304 stainless steel pipe is free of stains. After grinding off the surface coating, a drop of measuring solution to remove the coating, observe the colour change of the 304 stainless steel pipe in the test area, you can judge the colour or the time it turns red.

Spark observation: 
304 stainless steel tube cutting or welding sparks and hardness can also distinguish the quality of stainless steel tube.

Zhejiang Bewell® Steel Industry Co.,Ltd.  is a professional manufacturer, processor and seller of seamless pipes, welded pipes, pipe fittings, flanges, steel rods and other finished products made of Bewell® stainless steel, duplex steel, high nickel alloy and other materials in China. We have specialized in steel manufacturing for nearly 10 years, and have won the trust of our customers with strong technical support, good quality and service timely and accurate delivery, and have developed a business pattern of dual-driven foreign trade and domestic sales.Welcome new and old customers to come and buy.