Causes of ASTM A53 seamless steel pipe crack:
First, the reasons for the tube (round) mostly, the internal contains more cracks, inclusions, air bags and so on. Uneven organization of the tube is the reason, pay attention to the choice of the implementation of tube standard, there is a certain size of the manufacturer of the round bar on the line.
Second, the perforation temperature, process adjustment can not be ignored, if the piercing temperature is low, improper adjustment, can also cause the tearing of the capillary tube internal organization.
Third, the finish annealing temperature is suitable. Perforated heating temperature 1180 ~ 1230 ℃, low, this is the temperature of carbon steel, take 1230-1250 was appropriate. Furnace time is generally more than 60min.
2017年1月17日星期二
Control Measures of ASTM A53 Seamless Steel Tube Side
In all steel pipe, ASTM A53 seamless steel tube occupies a large proportion, but the actual production of seamless steel pipe is often used in controlled rolling and cooling technology, easy to control the process of cooling due to uneven cooling plate defects, seriously affecting product quality and contract cash . Plate side wave is one of the more serious one.
Seamless steel tube side of the wave-shaped defects are due to uneven cooling caused by lateral. On-site tracking found that there are obvious on both sides of the side wave plate "band-shaped supercooled" area. The transverse cooling caused by uneven factors are:
1) There are transverse temperature differences between the center and the sides of the seamless tube.
2) seamless steel pipe in the controlled rolling process, the middle and edge there is a large temperature difference.
3) The finish rolling mill adopts "CVC" rolling process, which is caused by the difference of the two sides of the steel plate and the middle extension, which causes the internal stress of the steel plate, which does not reach the degree of bilateral wave shape. , But is further increased during the subsequent cooling.
4) In the process of controlling the cooling process of seamless steel pipe, not only the transformation of the structure occurs with the change of temperature, but also the complex stress change occurs.
Seamless steel tube side of the wave-shaped defects are due to uneven cooling caused by lateral. On-site tracking found that there are obvious on both sides of the side wave plate "band-shaped supercooled" area. The transverse cooling caused by uneven factors are:
1) There are transverse temperature differences between the center and the sides of the seamless tube.
2) seamless steel pipe in the controlled rolling process, the middle and edge there is a large temperature difference.
3) The finish rolling mill adopts "CVC" rolling process, which is caused by the difference of the two sides of the steel plate and the middle extension, which causes the internal stress of the steel plate, which does not reach the degree of bilateral wave shape. , But is further increased during the subsequent cooling.
4) In the process of controlling the cooling process of seamless steel pipe, not only the transformation of the structure occurs with the change of temperature, but also the complex stress change occurs.
2017年1月4日星期三
Notes in Making API 5L Seamless Steel Tube Equipment
Notes in making API 5L seamless steel tube equipment
A. Oil Marking: Water pressure testing machine after passing the steel pipe to prevent oil corrosion, and marking in accordance with user requirements.
B. Leveling Milling: The original steel plate is flattened by an anvil press, and then the two edges of the steel plate are milled by the edge milling machine to achieve the required plate width, parallelism and groove shape.
C. Shear forming: the steel plate in the production line spiral along the outer curl into a tube.
D. Butt welding: Seamless steel pipe equipment market uses advanced double-sided submerged arc welding technology for pre-welding, welding, external welding. The welded steel pipe is cut to a gauge length using a plasma bar.
E. Visual inspection: Some basic parameters are checked by professional technicians.
F. Ultrasonic flaw detection: the development of scrap steel on both sides of the internal and external welds and base metal 100% inspection.
G. X-ray inspection: 100% of the internal and external weld X-ray industrial television inspection, the use of image processing systems to ensure the detection sensitivity.
H. Pressure test: in the hydraulic pressure testing machine on the steel pipe to the root-by-root test to ensure that the steel pipe to achieve the required standard test pressure.
I. Chamfer flat head: seamless steel pipe equipment will be tested after the pipe end pipe processing, to achieve the required pipe end (spiral welded pipe unit) groove size.
J. Final inspection: the straightening machine again ultrasonic and X-ray inspection and the end of the magnetic powder test to check the existence of welding problems and pipe-end defects.
K. Uncoiler plate exploration: After the steel plate is opened into the production line, the first full-plate ultrasonic inspection.
A. Oil Marking: Water pressure testing machine after passing the steel pipe to prevent oil corrosion, and marking in accordance with user requirements.
B. Leveling Milling: The original steel plate is flattened by an anvil press, and then the two edges of the steel plate are milled by the edge milling machine to achieve the required plate width, parallelism and groove shape.
C. Shear forming: the steel plate in the production line spiral along the outer curl into a tube.
D. Butt welding: Seamless steel pipe equipment market uses advanced double-sided submerged arc welding technology for pre-welding, welding, external welding. The welded steel pipe is cut to a gauge length using a plasma bar.
E. Visual inspection: Some basic parameters are checked by professional technicians.
F. Ultrasonic flaw detection: the development of scrap steel on both sides of the internal and external welds and base metal 100% inspection.
G. X-ray inspection: 100% of the internal and external weld X-ray industrial television inspection, the use of image processing systems to ensure the detection sensitivity.
H. Pressure test: in the hydraulic pressure testing machine on the steel pipe to the root-by-root test to ensure that the steel pipe to achieve the required standard test pressure.
I. Chamfer flat head: seamless steel pipe equipment will be tested after the pipe end pipe processing, to achieve the required pipe end (spiral welded pipe unit) groove size.
J. Final inspection: the straightening machine again ultrasonic and X-ray inspection and the end of the magnetic powder test to check the existence of welding problems and pipe-end defects.
K. Uncoiler plate exploration: After the steel plate is opened into the production line, the first full-plate ultrasonic inspection.
Status Analysis of API 5L Seamless Steel Pipe
API 5L seamless tube is characterized by a large diameter, wall thickness is relatively thick, so according to this feature make full use of ultrasonic detection of eddy current and internal and secondary surface detection features combined to achieve "no blind spot" testing. Through the use of "steel pipe rotation, detection probe forward combination", not only solve the problem of detecting the title, but also solve the space occupied by narrowing the space.
Therefore, at home and abroad for the seamless pipe testing, the general use of magnetic flux leakage test or water pressure. In China, there is no good performance for the seamless magnetic flux leakage detection equipment produced, once the use of that need to import. Imported magnetic flux leakage testing equipment is expensive, the majority of domestic enterprises difficult to accept; and water pressure test efficiency is low, labor-intensive, especially when the operator responsibility is not high, the water pressure test in name only. Can be seen, to achieve large-diameter seamless steel pipe inspection has become a metallurgical steel pipe industry to be solved.
Sink ultrasonic testing is the use of steel spiral forward, ultrasonic probe fixed. Through the sink and the bottom of the steel pipe was fully coupled to the characteristics of the coupling layer thickness to ensure the same. But because the main detection of internal defects on the surface of the surface and sub-surface defects in the existence of blind spots, resulting in undetectable, coupled with the use of spiral-type, for 12m long steel pipe needs space 30m and other deficiencies, has affected the choice of steel detection methods and Promotion.
The through-coil eddy current detects a circumferential surface of the steel pipe surface. In the use of through-coil eddy current inspection, the greater the diameter of the pipe being detected, the greater the area of the coil to detect the circle, the lower the signal to noise ratio. It is for this reason, eddy current testing standards, the use of through-coil eddy current testing, the size of its foreign economy shall not exceed 140mm. In addition, the seamless pipe through the type of testing, the magnetization and demagnetization of steel and so there is a certain degree of difficulty.
At present, China's metallurgical industry for high-pressure boiler seamless steel pipe testing mainly concentrated in the following specifications φ160mm, and most of the traditional through-coil eddy current testing or independent tank ultrasonic testing method. For more than φ160mm seamless steel pipe using the traditional through-type eddy current method for testing, there are a lot of title, but also the national standards are not allowed. Such as the use of independent ultrasonic testing, the existence of a certain depth of the ultrasonic detection mechanism of the blind spot, can not guarantee the reliability of the overall test results.
Therefore, at home and abroad for the seamless pipe testing, the general use of magnetic flux leakage test or water pressure. In China, there is no good performance for the seamless magnetic flux leakage detection equipment produced, once the use of that need to import. Imported magnetic flux leakage testing equipment is expensive, the majority of domestic enterprises difficult to accept; and water pressure test efficiency is low, labor-intensive, especially when the operator responsibility is not high, the water pressure test in name only. Can be seen, to achieve large-diameter seamless steel pipe inspection has become a metallurgical steel pipe industry to be solved.
Sink ultrasonic testing is the use of steel spiral forward, ultrasonic probe fixed. Through the sink and the bottom of the steel pipe was fully coupled to the characteristics of the coupling layer thickness to ensure the same. But because the main detection of internal defects on the surface of the surface and sub-surface defects in the existence of blind spots, resulting in undetectable, coupled with the use of spiral-type, for 12m long steel pipe needs space 30m and other deficiencies, has affected the choice of steel detection methods and Promotion.
The through-coil eddy current detects a circumferential surface of the steel pipe surface. In the use of through-coil eddy current inspection, the greater the diameter of the pipe being detected, the greater the area of the coil to detect the circle, the lower the signal to noise ratio. It is for this reason, eddy current testing standards, the use of through-coil eddy current testing, the size of its foreign economy shall not exceed 140mm. In addition, the seamless pipe through the type of testing, the magnetization and demagnetization of steel and so there is a certain degree of difficulty.
At present, China's metallurgical industry for high-pressure boiler seamless steel pipe testing mainly concentrated in the following specifications φ160mm, and most of the traditional through-coil eddy current testing or independent tank ultrasonic testing method. For more than φ160mm seamless steel pipe using the traditional through-type eddy current method for testing, there are a lot of title, but also the national standards are not allowed. Such as the use of independent ultrasonic testing, the existence of a certain depth of the ultrasonic detection mechanism of the blind spot, can not guarantee the reliability of the overall test results.
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