1. Material problem

Many enterprises use irregular materials, usually referring to the nickel content. Although liquid medicine can be used to distinguish, it is obvious that this is a misunderstanding, because only more than 7 nickel in small furnace charge can not be distinguished. However, the price of raw materials varies greatly, which is one of fraud. In particular, the counterfeiting of 321 high nickel and 316 high nickel is very serious.

2. Dimension problem

Many customers basically do not have technical support for inspection. For example, 90 degree elbow, the conventional is r = 1.5D, but looking at the Wenzhou market, most of the production molds are 1.25d. Don't write this 0.25D ~ ~ but the weight of the materials in it is very different. That is, the so-called factory logo is much shorter than the standard.

3. Thickness problem

Of course, today's customers are very smart and can measure the thickness with a caliper. Although sometimes customers feel that they are barely up to the standard after inspection, they ignore that the thickness of the back arc is not enough!!! Because the wall of the elbow will be reduced during the pushing process, the caliber is barely up to the standard, while the back is basically unqualified. Generally, experts know that 114x4 thick pipes are mostly used for the production of 114x3.5 elbows. If the manufacturer purchases thinner products, the natural loss will be reduced a lot, but the products will become more superficial and meet the surface standards.

4. Solution treatment and NDT, sand rolling treatment and sand blasting treatment

Many manufacturers in the market do not do solid solution treatment and 100% penetration nondestructive testing, and many of them use sand blasting instead of rolling sand. After these steps are omitted, the cost is greatly reduced.

5. Seamless welding

Seamless welding means that the welded elbow is sandblasted after grinding and pickling, and there is no sign of welding on the surface. Even with advanced flaw detection equipment, it can not be seen that it is a welded elbow.