1. Material problem of SMLS pipe material
Many companies use more materials and materials, usually referring to the amount of nickel. Although it can be used to distinguish medicine, it is obvious that this is a misunderstanding, because small charge can only be identified by more than 7 nickel. But the price difference between raw materials is very large. This is one of the fake products. In particular, 321 of high nickel and 316 of high nickel forgery are very serious.
2. SMLS pipe size problem
Many customers have basically no technical support for testing. For example, 90 degree elbow, the traditional is R = 1.5 D, but the Wenzhou market is basically more than 1.25D mold production, do not underestimate the weight of the 0.25D~~ inside, but the difference is very big. This is the so-called factory standard, far below the standard.
Three. The thickness of SMLS pipe material
Of course, now the customer is very smart, will use a caliper to measure the thickness, although sometimes the customer feels reluctant to observe, but neglects a little, that is to say, the thickness of the back arc is not enough! Because the elbow pushing process will be cut off, so the caliber is barely observed.
4. SMLS pipe
sand treatment and sandblasting treatment and NDT
Many manufacturers do not carry out solution treatment and 100% osmosis nondestructive testing in the market. This also has a large amount of sand blasting instead of sand, which saves these steps and greatly reduces the cost.
5. Seamless welding
Welding seamless, is to do welding elbow, after grinding and acid washing after the sand, there is no sign of the surface of the welding, even the use of advanced testing equipment can not see it is the welding elbow.
6. Spot welding and repair welding
The elbow pushing process will become thinner, so in general, manufacturers will use thicker pipes. If you use thin raw materials, it is definitely not qualified. Under normal circumstances, the filament is about 40, which is much lower than the standard if the process is poor or the drawing tube is used.