1. Material issues Many enterprises use the material more irregular, usually refers to nickel content. Although it can be used to distinguish between, but it is obvious that this is a misunderstanding, because the small burden of nickel containing only 7 more can not be distinguished. But the price difference between raw materials is very large, this is one of the false.
In particular, 321 high nickel and 316 high nickel is very serious.
2. Dimension problem Many customers basically do not have the technical support of inspection. For example, 90-degree elbow, the conventional is r=1.5d, but throughout the Wenzhou market basically produces more than 1.25D of mold, do not underestimate the weight of the material inside the 0.25d~~ is very different.
The so-called factory standard is much shorter than the standard.
3. Thickness problem Of course, now the customer is very smart, will use caliper to measure thickness, although sometimes customers feel reluctantly after testing, but overlooked a point, is not the thickness of the back arc!!! Because the elbow push process will have to reduce the wall, so the caliber is barely up to standard, and the back solitary is basically unqualified, the general expert more understanding, 114x3.5 elbow more will use 114x4 thick pipe to produce.
If the manufacturer buys a bit thinner, the natural loss reduces a lot, but the product also becomes above the superficial appearance, the surface standard only.
4. Solid solution treatment and nondestructive testing sand treatment and sandblasting treatment
Many manufacturers on the market do not do solid solution treatment and hundred-percent penetration nondestructive testing, there are many use sand blasting instead of sand, save these several steps, greatly reduce the cost.
5. Welding Seamless
Welding seamless, is to do the welding elbow, after grinding and pickling blasting, the surface without any signs of welding, even the use of advanced flaw detection equipment can not see it is welded elbow.
6. Spot welding, repair welding Elbow push process will appear thinning, so under normal circumstances, manufacturers will use more thick pipe. If the use of thin raw materials, the production is certainly unqualified.
In general, the thinning has about 40 silk, such as poor technical or use of drawn tubing, the thickness is significantly lower than the standard many. At this point if the welding wire with the same material thickness is insufficient, welded to a certain thickness of the sand blasting, there are cracks in the place to take the repair welding, even if the opening of a large cut pipe, can be made up.