Features And Causes Of Eight Defects Of Seamless Steel Pipe

Features and causes of eight defects of seamless steel pipe:folding, crack, scratches, pit, pitted floor, spots, warped pores and skin, scar.

If there are some defects within the seamless steel pipe, it’s going to undoubtedly have a fatal affect on the quality of our merchandise. So how one can keep away from these defects? Then you definitely want to grasp the reasons for these defects. Permanent Steel Manufacturing Co.,Ltd will work with you to discuss the particular causes for the 8 defects of seamless steel pipes:

1. Seamless steel pipe-folding

It is a linear or spiral, continuous or discontinuous state that exists on the outer or inside floor of seamless steel pipe. The primary cause for the folding is poor high quality of the pipe material, folding itself, or inclusions, serious scratches and cracks on the surface, edges and corners in the grinding place, and folding after drawing. So as to avoid folding, the standard of the pipe materials must be improved and a spotlight ought to be paid to inspection and grinding.

2. Seamless steel pipe-crack

Refers to the small cracks on the inner and outer surfaces of the seamless steel pipe which might be distributed in a straight line or a spiral, with a depth of 1 mm or more, continuous and discontinuous. In keeping with the analysis of Permanent Steel Manufacturing Co. If you beloved this article and you would like to collect more info relating to seamless steel tube price kindly visit the web page. , Ltd, the trigger is: the hot-rolled tube clean has subcutaneous bubbles and subcutaneous inclusions, and there are cracks or deep pits on the steel pipe earlier than drawing. During the recent rolling or chilly drawing processes Longitudinal scratches or scratches occurred throughout the operation. Preventing the formation of cracks additionally lies in bettering the standard of the tube blank and strengthening the inspection and grinding of the tube material. At the same time, pitting, scratches and scratches needs to be prevented throughout the chilly drawing manufacturing process.

3. Seamless steel pipe-scratches

The characteristic of the defect is that there are longitudinally linear scratches of varying lengths on the interior and outer surfaces of the seamless pipe. Most of them are groove-formed, however they could even be raised stripes. The primary reason for the scratches (cutting) is: there are internal markings on the pipe material, which can’t be eliminated throughout drawing, the iron oxide movie stays on the steel pipe and the mold sticks to the steel, and the power and hardness of the mold are insufficient or uneven. Fragmentation and wear occur, the hammer head is defective, and the sharp edges and corners of the hammer head transition half injury the mold. In order to prevent scratches and scratches, the quality of each preparation process before drawing ought to be improved, and molds with excessive strength and hardness and good smoothness ought to be used.

4. Seamless steel pipe-pit

This is one in every of the most common surface defects of seamless pipes. Local depressions with different areas are distributed on the floor of the steel pipe. Some of them are periodic and a few are irregular. The pits are brought on by iron oxide scale or different arduous dirt pressed into the floor of the steel pipe throughout the drawing or straightening process, or the peeling of the unique peeling on the floor of the steel pipe. Shandong Jute Pipe Industry identified that the measures to stop pits are to fastidiously inspect the pipe material and remove defects reminiscent of warping, keep the work site, instruments and lubricants clean, and prevent oxide scale and dirt from falling on the floor of the steel pipe.

When there are clean or sharp spiral marks on the outer floor of the seamless steel pipe, the straightening machine must be checked. As a result of incorrect place and angle of the straightening roller, the steel pipe rubbed the shoulders on the sting of the straightening roller during straightening. There are worn grooves on the straightening roller, and both ends of the steel pipe might seem on the outer surface of the steel pipe. Pits.

5. Seamless steel pipe-pitted floor

It is characterized by small pits within the type of items and dots on the surface of the steel pipe. The main cause for the pitting floor is pitting corrosion during pickling. After annealing, the oxide scale is simply too thick and straightened and pressed into the floor of the steel pipe to kind a pitted surface; the steel pipe is kept in a humid environment, and even pitted rust happens after water enters. After eradicating the rust spots Form pitted floor.

6. Seamless steel pipe-spots

Since seamless steel pipes are involved with water (or water vapor) during processing or storage and should not treated in time (comparable to drying), the traces left by water evaporation are referred to as water spots, reminiscent of lengthy contact with water or corrosive water Rust spots are formed when the substance is Water spots usually have no depth, and rust spots usually corrode the floor of the steel pipe, and there’ll nonetheless be pitted surfaces after removal.

7. Seamless steel pipe-warped skin

It’s characterized in that the inside and outer surfaces of the seamless steel pipe are partially separated from the steel substrate, and the person items are lumpy, discontinuous, rooted or not rooted on the pipe wall, but can not peel off naturally. The explanations are poor steel high quality, the existence of subcutaneous bubbles, that are exposed after cold drawing; the warping produced during hot rolling isn’t eliminated on the tube billet to chilly drawing; the unique deep and angular transverse pits on the steel tube After drawing, it types a warped skin.

8. Seamless steel pipe-scar

The inner and outer surfaces of the steel pipe weren’t eliminated in time attributable to defects similar to folding and warping. In the following processing, thin slices that couldn’t be separated from the metal substrate had been formed. A few of them have been lumpy, discontinuous, and rooted or not rooted on the pipe wall, but they couldn’t peel off naturally. , Called scarring. Surface defects should be checked and removed in time to eradicate scars.

Tips: ASTM A53 Grade B is extra fashionable than different grades. These pipes may be naked pipes with none coating, or it may be Hot-Dipped or Zinc-Coated and manufactured by Welding or by a Seamless manufacturing course of. In Oil and Gas, A53 grade pipes are used within the structural and non-essential functions.

In the appliance of submarine oil and fuel pipeline engineering, ERW welded pipes are safe and economical.






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