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

If there are some defects within the seamless steel pipe, it can undoubtedly have a fatal influence on the quality of our merchandise. So how to avoid these defects? You then want to know the explanations for these defects. Permanent Steel Manufacturing Co.,Ltd will work with you to debate the particular reasons for the 8 defects of seamless steel pipes:

1. Seamless steel pipe-folding

It’s a linear or spiral, continuous or discontinuous state that exists on the outer or inner surface of seamless steel pipe. The principle motive for the folding is poor quality of the pipe materials, folding itself, or inclusions, serious scratches and Alloy Tube Supply cracks on the surface, edges and corners in the grinding place, and folding after drawing. In order to avoid folding, the standard of the pipe materials should 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 inside and outer surfaces of the seamless steel pipe which can be distributed in a straight line or a spiral, with a depth of 1 mm or more, continuous and discontinuous. In line with the evaluation of Permanent Steel Manufacturing Co., Ltd, the cause is: the new-rolled tube blank has subcutaneous bubbles and subcutaneous inclusions, and there are cracks or deep pits on the steel pipe before drawing. During the hot rolling or cold drawing processes Longitudinal scratches or scratches occurred in the course of the operation. Preventing the formation of cracks additionally lies in enhancing the standard of the tube clean and strengthening the inspection and grinding of the tube materials. At the identical time, pitting, scratches and scratches must be averted through the chilly drawing production process.

3. Seamless steel pipe-scratches

The characteristic of the defect is that there are longitudinally linear scratches of various lengths on the inside and outer surfaces of the seamless pipe. Most of them are groove-formed, but they might even be raised stripes. The primary reason for the scratches (chopping) is: there are inner markings on the pipe materials, which cannot be eliminated during drawing, the iron oxide movie remains on the steel pipe and the mold sticks to the steel, and the energy and hardness of the mold are inadequate 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 forestall scratches and scratches, the quality of each preparation process earlier than drawing ought to be improved, and molds with excessive strength and hardness and good smoothness must be used.

4. Seamless steel pipe-pit

This is one in all the most typical surface defects of seamless pipes. Local depressions with different areas are distributed on the floor of the steel pipe. A few of them are periodic and some are irregular. The pits are attributable to iron oxide scale or different laborious dirt pressed into the surface of the steel rod pipe during the drawing or straightening process, or the peeling of the original peeling on the surface of the steel pipe. Shandong Jute Pipe Industry identified that the measures to stop pits are to rigorously examine the pipe materials and remove defects such as warping, keep the work site, instruments and lubricants clean, and stop oxide scale and dirt from falling on the floor of the steel pipe.

When there are easy or sharp spiral marks on the outer floor of the seamless steel pipe, the straightening machine needs to be checked. Because of the incorrect position and angle of the straightening roller, the steel pipe rubbed the shoulders on the sting of the straightening roller throughout straightening. There are worn grooves on the straightening roller, and each ends of the steel pipe might seem on the outer floor of the steel pipe. Pits.

5. Seamless steel pipe-pitted surface

It is characterized by small pits within the form of items and dots on the surface of the steel pipe. The primary motive for the pitting floor is pitting corrosion during pickling. After annealing, the oxide scale is just too thick and straightened and steel pipe pressed into the floor of the steel pipe to kind a pitted floor; the steel pipe is kept in a humid surroundings, and even pitted rust happens after water enters. Here’s more in regards to alloy tube supply visit our own web site. After removing the rust spots Form pitted surface.

6. Seamless steel pipe-spots

Since seamless steel pipes are involved with water (or water vapor) throughout processing or storage and should not treated in time (equivalent to drying), the traces left by water evaporation are known as water spots, akin to long contact with water or corrosive water Rust spots are formed when the substance is Water spots usually haven’t any depth, and rust spots typically corrode the floor of the steel pipe, and there will still be pitted surfaces after elimination.

7. Seamless steel pipe-warped skin

It is characterized in that the internal and outer surfaces of the seamless steel pipe are partially separated from the steel substrate, and alloy pipe the person pieces are lumpy, discontinuous, rooted or not rooted on the pipe wall, but cannot peel off naturally. The explanations are poor steel high quality, the existence of subcutaneous bubbles, that are exposed after chilly drawing; the warping produced throughout 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 pores and skin.

8. Seamless steel pipe-scar

The inside and outer surfaces of the steel pipe were not removed in time because of defects akin to folding and warping. In the following processing, skinny slices that could not be separated from the metallic substrate had been formed. A few of them were lumpy, discontinuous, and rooted or not rooted on the pipe wall, but they could not peel off naturally. , Called scarring. Surface defects have to be checked and removed in time to eliminate scars.

Tips: ASTM A53 Grade B is more well-liked than other grades. These pipes might be naked pipes with none coating, or it could also be Hot-Dipped or Zinc-Coated and manufactured by Welding or by a Seamless manufacturing process. In Oil and Gas, A53 grade pipes are used within the structural and non-essential applications.

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


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