Differences Between Seamless Casing and ERW Casing Pipe

In line with the manufacturing methodology, the metal pipe could be divided into two classes: seamless metal pipe and welded seam metal pipe. Amongst them, ERW metal pipe is the principle number of welded metal pipe. Right now, we primarily discuss two sorts of metal pipes used as uncooked supplies for petroleum Casing pipe: Seamless casing and ERW casing.

Seamless casing – Casing made from seamless metal pipe as uncooked materials;

Seamless metal tubes seek advice from metal tubes manufactured by 4 strategies: scorching rolling, chilly rolling, scorching drawing, and chilly drawing. There aren’t any welds on the pipe physique itself.

ERW casing – Casing made of electrical welded pipe as uncooked materials

ERW (Electrical Resistant Weld) metal pipe refers to a straight seam welded pipe manufactured via a high-frequency resistance welding course of. The uncooked materials metal plate (coil) of ERW welded pipe is made from low-carbon microalloy metal rolled by TMCP (Thermo-Mechanical Management Course of).

1. Outer diameter tolerance

Seamless metal pipe: Sizzling-rolled forming course of is used, and the sizing is accomplished at about 8000C. The uncooked materials composition, cooling situation and cooling state of the curler have an incredible affect on its outer diameter, so the outer diameter management is tough to be correct and fluctuates The vary is bigger.

ERW metal pipe: adopts cold-formed forming and sizing by 0.6% discount. The method temperature is principally fixed at room temperature, so the outer diameter management is correct and the fluctuation vary is small, which is useful to get rid of black leather-based buckles;

2. Wall thickness tolerance

Seamless metal pipe: It’s produced by spherical metal perforation, and the wall thickness deviation is massive. The following scorching rolling can partially get rid of the unevenness of the wall thickness, however essentially the most superior unit can solely be managed inside ±5~10percentt.

ERW metal pipe: utilizing hot-rolled coil as uncooked materials, the thickness tolerance of recent hot-rolling could be managed inside 0.05mm.

3. Look

The outer floor defects of the blanks utilized in seamless metal pipes can’t be eradicated by the recent rolling course of, and the defects can solely be polished off after the completed product is completed; the spiral path left after perforation can solely be partially eradicated within the wall discount course of.

ERW metal pipe makes use of hot-rolled coils as uncooked supplies. The floor high quality of the coils is the floor high quality of ERW metal pipes. The floor high quality of hot-rolled coils is straightforward to regulate and excessive in high quality. Due to this fact, the floor high quality of ERW metal pipes is a lot better than seamless metal pipes.

4. Ovality

Seamless metal pipe: hot-rolled forming course of is adopted. The uncooked materials composition of the metal pipe, the cooling situation and the cooling state of the roll have an incredible affect on its outer diameter, so it’s tough to regulate the outer diameter precisely and the fluctuation vary is massive.

ERW metal pipe: adopts chilly bending forming, so the outer diameter management is correct and the fluctuation vary is small.

5. Tensile check

The tensile efficiency indexes of seamless metal pipes and ERW metal pipes conform to API requirements, however the energy of seamless metal pipes is usually on the higher restrict and the plasticity is on the decrease restrict. Compared, the energy index of ERW metal pipes is in the perfect state, and the plasticity index is 33.3% increased than the usual. The reason being that the efficiency of hot-rolled coils, the uncooked materials of ERW metal pipes, is assured by way of microalloying smelting, out-of-furnace refining, and managed chilly and managed rolling; seamless metal pipes primarily depend on means to extend carbon content material, which is tough to make sure energy and plasticity. Cheap match.

6. Hardness

The uncooked materials of ERW metal pipe, hot-rolled coil, has extraordinarily excessive precision throughout the rolling course of, which might make sure the uniform efficiency of all components of the coil.

7. Grain dimension

The uncooked materials of ERW metal pipe-hot-rolled coils are made from broad and thick steady casting billets, with a thicker fine-grained floor solidification layer, no columnar crystal areas, shrinkage and porosity, small composition deviation, and compact construction; within the subsequent rolling course of The applying of managed chilly and managed rolling know-how additional ensures the grain dimension of uncooked supplies.

8. Anti-collapse check

ERW metal pipe is as a result of traits of its uncooked supplies and pipe making course of. Its wall thickness uniformity and ellipticity are far superior to seamless metal pipes, which is the principle purpose why the collapse resistance efficiency is increased than that of seamless metal pipes.

9. Impression check

Because the influence toughness of the bottom materials of ERW metal pipe is a number of occasions that of seamless metal pipe, the influence toughness of the weld is the important thing to ERW metal pipe. By controlling the impurity content material of uncooked supplies, the peak and course of slitting burrs, the form of forming edges, the welding angle, and the welding velocity , Heating energy and frequency, welding extrusion quantity, intermediate frequency withdrawal temperature and depth, air cooling part size and different course of parameters be sure that the influence vitality of the weld reaches greater than 60% of the bottom steel. If additional optimized, the weld influence vitality could be near the bottom Materials to attain seamless efficiency.

10. Blasting check

The blasting check efficiency of ERW metal pipe is way increased than the usual requirement, primarily as a result of excessive uniformity of wall thickness and uniform outer diameter of ERW metal pipe.

11.Straightness

The seamless metal pipe is shaped in a plastic state, and the straightness of the pipe finish is comparatively tough to regulate with the only ruler (3 to 4 occasions ruler for steady rolling);

ERW metal pipe is cold-worked, and it has on-line straightening within the state of lowering diameter. As well as, it’s infinite occasions, so the straightness is healthier.

12.The consumption of metal for 10,000-meter footage casing

The wall thickness of ERW metal pipe is uniform, and its wall thickness tolerance could be ignored. The management accuracy restrict of seamless metal pipe wall thickness distinction is ±5percentt, and it’s usually managed at ±5-10percentt. With the intention to be sure that the minimal wall thickness can meet the usual necessities and efficiency, the answer can solely be solved by appropriately rising the wall thickness. Due to this fact, within the casing of the identical specification and the identical weight, the ERW metal pipe is 5-10% longer than the seamless metal pipe, or much more, which reduces the metal consumption of the casing for 10,000 meters by 5-10%. Even on the similar worth, ERW casing nearly saves customers 5-10% of buying prices.

To sum up:

So far as the present home and overseas conditions are involved, it’s extra seamless to make use of. As a result of ERW’s present casing metal grade can solely be managed on the highest K55, if the metal grade is increased, China doesn’t have this manufacturing capability. So far as the present ERW market is worried, Japanese manufacturing gear and manufacturing are nonetheless used for casing. The method can attain a sure degree, however it may well solely be produced to N80. If you wish to produce metal grades of P110 or increased, it’s at present tough, so ERW can solely be used for floor casing.

Suggestions: ERW welded pipe is shaped by rolling strip and welding the seam, with tighter dimensional tolerances and fewer weight. The weld seam is warmth handled after welding that no untempered martensite stays, and the weld flash could be faraway from each inside and outer surfaces.

ASTM A53 ERW metal pipe is a typical carbon metal pipe. It’s largely used to convey fluids at low / medium pressures reminiscent of oil, gasoline, steam, water, air and likewise for mechanical functions.