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Purchase pipe fittings need to pay attention to several issues
Feb 11, 2019
  1. Material problem

The material that a lot of enterprises use is more informal, often point to contain nickel content.Although you can use the liquid to distinguish, but it is obvious that this is a mistake, because the small furnace charge containing nickel only 7 more is not able to distinguish.But the price difference of raw material is very big however, this is one of make false.Especially 321 high nickel and 316 high nickel are very serious to fake.


2. Size problem


Many customers have little or no technical support for testing.For example, 90 degree elbow, the conventional is R= 1.5d, but throughout the wenzhou market basically produce mold is 1.25d, do not underestimate the weight of this 0.25D~~ inside the material is very different.That is to say, the factory standard is much shorter than the standard.


3. Thickness problem


Of course, now the customer is very smart, will use calipers to measure the thickness, although sometimes the customer after the test feel reluctantly up to the standard, but ignored a point, is the thickness of the back arc is not enough!!!Because there will be wall reduction in the process of elbow pushing, the caliber is barely up to the standard, while the back end is basically unqualified, as the general experts know, 114x3-5 elbow will mostly use 114X4 thick pipes to produce.If the manufacturer purchases a little thinner, the natural loss will be reduced a lot, but the product will become more than a facade, the surface standards.


4. Solid solution treatment and nondestructive testing


Many manufacturers in the market do not do solid solution treatment and 100% penetration of non-destructive testing, which have a lot of sandblasting instead of rolling sand, save these steps, greatly reduce the cost.


5. Seamless welding


Welding seamless, is to do welding elbow, after grinding and pickling sand blasting, the surface without any signs of welding, even using advanced flaw detection equipment can not be seen that it is a welding elbow.


6. Spot welding and repair welding


Elbow push process will appear in the thin, so generally manufacturers will use a little thicker pipe.If the use of thin raw materials, the production will certainly not qualified.Reduce commonly thin have 40 silk left and right sides, if the technology is bad or use the pipe material that draw, ply is under standard apparently a lot of.


At this time, if the same material welding wire spot welding thickness is insufficient, to a certain thickness of grinding sand blasting, cracks in the place to take the repair welding, even with a large hole in the steel tube, can be made up for a time.