The difference between seamless stainless steel pipe and welded stainless steel pipe:

1. The pipe making process is different.

Seamless stainless steel pipe, also known as seamless stainless steel pipe, is made of steel ingot or solid billet by piercing into a rough tube, and then made by hot rolling, cold rolling or cold dialing.

Welded stainless steel pipe is made of stainless steel plate.

2. welded seam.

Decorative 304 stainless steel welded pipe due to the pipe making process to see is a welded seam, but seamless steel pipe like its name is no welded seam. Good quality decorative stainless steel welded pipe, welded seams all do nitrogen internal protection.

3. Thickness.

Stainless steel welded pipe raw material steel strip are calendered, the thickness is more uniform, welded pipe finished specifications, the thickness is a thin tube has a thick tube. But the thickness of seamless stainless steel tube is often uneven, and are thicker tubes.

4. Welding performance.

Usually, the general 304 seamless stainless steel pipe and seamless stainless steel pipe chemical composition there are some differences. Production of seamless stainless steel pipe steel composition is only to meet the basic requirements of astm. For the production of welded stainless steel pipe steel, contains chemical composition suitable for welding, such as silicon, sulfur, manganese, oxygen and ferrite and other elements in a certain proportion of the mixture can be produced in the welding process of an easy to transfer the heat of the weld fusion, thus making the entire weld weld penetration. Seamless stainless steel pipe, due to the lack of the above elements, in the welding process will produce a variety of unstable factors, not easy to weld and weld through.

4. Corrosion resistance.

In general, the same material material two stainless steel pipe and seamless pipe corrosion resistance, basically the same.

5. Price.

Seamless steel pipe price is higher than the welded stainless steel pipe.

6. Comprehensive quality

Generally speaking, the quality of 304 seamless stainless steel pipe is better than seamless stainless steel pipe. This is because the welded stainless steel pipe is made of precise cold rolled plate that has been tested and passed, so the defects are basically in the welds. While the 304 seamless stainless steel pipe is made of stainless steel billet stamped by a punch, resulting in many tears in the wall of the pipe formed by extrusion. Eddy current testing has shown that the defective rate of seamed stainless steel pipe will usually be lower than the defective rate of seamless stainless steel pipe.

6. Surface.

Seamless tube surface requirements are not strict, there will be less obvious spots. Stainless steel decorative tube surface treatment requirements are more stringent.

7. Use.

Seamless pipe is mainly industrial pipe. Decorative tube is more widely used, mainly in the field of decorative welding, but as the decorative stainless steel tube process is getting better and better, there is also a thick-walled decorative tube will replace some of the seamless steel tube.

Integrity management! :

Stainless steel seamless steel pipe is a kind of long steel with a hollow cross section and no seams around it.

Stainless steel welded steel pipe is also a kind of steel with a hollow cross-section, only it is welded through the plate rolled into a steel pipe, so the welded steel pipe has a welding seam.

Stainless steel seamless pipe features

First, the thicker the wall thickness of the product, the more economic and practical it is, the thinner the wall thickness, its processing costs will rise substantially; Second, the product's process determines its limitations performance, the general seamless steel pipe precision is low: wall thickness is not uniform, the tube inside the appearance of the brightness is low, the cost of sizing is high, and the inside appearance and the pockmarks, black dots is not easy to remove; Third, it must be detected and shaping the offline processing. Therefore, it is in the high-pressure, high-strength, mechanical structure of the material reflects its superiority.

Types of stainless steel tube

Joint rolling method is divided into hot rolling, hot extrusion and cold drawn (rolled) stainless steel pipe.

According to the different stainless steel metallurgical organization of half-ferritic half-martensitic stainless steel tube, martensitic stainless steel tube, austenitic stainless steel tube, austenitic-ferritic stainless steel tube and so on.

Stainless steel pipe specifications and appearance quality

A, according to GB14975-94 “stainless steel seamless steel pipe” provisions, the usual length of the steel pipe (indefinite length) hot rolled steel pipe 1.5 ~ 10m, hot extrusion steel pipe equal to and greater than 1m. cold drawn (rolled) steel pipe wall thickness of 0.5 ~ 1.0mm, 1.0 ~ 7m; wall thickness greater than 1.0mm, 1.5 ~ 8m.

B, hot-rolled (hot-extruded) steel pipe diameter 54 ~ 480mm a total of 45 kinds; wall thickness 4.5 ~ 45mm a total of 36 kinds. Cold-drawn (rolled) steel pipe diameter 6 ~ 200mm total 65 kinds; wall thickness 0.5 ~ 21mm total 39 kinds.

C, the internal and external surfaces of the steel pipe shall not have cracks, folding, cracks, cracks, rolled folding, delamination and scarring defects exist, these defects should be completely removed (except for machining tubes), removal shall not make the wall thickness and outside diameter exceeds the negative deviation. Where not more than the permissible negative deviation of other minor surface defects may not be removed.

D, the permissible depth of the straight channel. Hot-rolled, hot-extruded steel pipe, diameter less than and equal to 140mm

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