1. Fake and inferior hot-rolled large-diameter seamless steel pipes are easy to scratch. The reason is that the facilities of the fake and inferior hot-rolled large-diameter seamless steel pipe manufacturers are simple and easy to produce burrs and scratch the surface of the steel. Deep scratches reduce the strength of steel.
2. Fake and inferior hot-rolled large-diameter seamless steel pipes have no metallic luster and are light red or similar to pig iron.
3. The cross ribs of the fake and inferior hot-rolled large-diameter seamless steel pipes are thin and low, and the phenomenon of dissatisfaction often occurs. The reason is that the manufacturer has to achieve large negative tolerances. Type full of dissatisfaction.
4. The cross-section of the fake and inferior hot-rolled large-diameter seamless steel pipe is elliptical. The reason is that in order to save material, the reduction of the first two passes of the finished roll is too large. The strength of this hot-rolled large-diameter seamless steel pipe will decrease. And it does not meet the standard of the external dimensions of hot-rolled large-diameter seamless steel pipes.
5. The composition of good hot-rolled large-diameter seamless steel pipes is uniform, the tonnage of the cold shearing machine is high, and the end face of the cutting head is smooth and neat, while the inferior hot-rolled large-diameter seamless steel pipe is often cut off due to poor material The phenomenon is that it is uneven and has no metallic luster. Moreover, because of the few cuts of the shoddy products, big ears will appear in the head and tail.
6. The material of fake and inferior hot-rolled large-diameter seamless steel pipe contains many impurities, the density of the steel is too small, and the size is severely out of tolerance, so it can be weighed and checked without a vernier caliper. Generally speaking, weighing mainly considers the problem of cumulative error and probability theory.
Tips:ASTM A500-Standard Specification for Cold-Formed Welded and Seamless Carbon Steel Structural Tubing in Rounds and Shapes.
According to ASTM A500, the weld seam location for square, rectangle and other specially shaped tubing shall not be located within the corner radius, unless specified by the customer or manufacturer.
Under ASTM A500, the corner radius for square and rectangular tubing shall not exceed three times the corner radius.
2. Fake and inferior hot-rolled large-diameter seamless steel pipes have no metallic luster and are light red or similar to pig iron.
3. The cross ribs of the fake and inferior hot-rolled large-diameter seamless steel pipes are thin and low, and the phenomenon of dissatisfaction often occurs. The reason is that the manufacturer has to achieve large negative tolerances. Type full of dissatisfaction.
4. The cross-section of the fake and inferior hot-rolled large-diameter seamless steel pipe is elliptical. The reason is that in order to save material, the reduction of the first two passes of the finished roll is too large. The strength of this hot-rolled large-diameter seamless steel pipe will decrease. And it does not meet the standard of the external dimensions of hot-rolled large-diameter seamless steel pipes.
5. The composition of good hot-rolled large-diameter seamless steel pipes is uniform, the tonnage of the cold shearing machine is high, and the end face of the cutting head is smooth and neat, while the inferior hot-rolled large-diameter seamless steel pipe is often cut off due to poor material The phenomenon is that it is uneven and has no metallic luster. Moreover, because of the few cuts of the shoddy products, big ears will appear in the head and tail.
6. The material of fake and inferior hot-rolled large-diameter seamless steel pipe contains many impurities, the density of the steel is too small, and the size is severely out of tolerance, so it can be weighed and checked without a vernier caliper. Generally speaking, weighing mainly considers the problem of cumulative error and probability theory.
Tips:ASTM A500-Standard Specification for Cold-Formed Welded and Seamless Carbon Steel Structural Tubing in Rounds and Shapes.
According to ASTM A500, the weld seam location for square, rectangle and other specially shaped tubing shall not be located within the corner radius, unless specified by the customer or manufacturer.
Under ASTM A500, the corner radius for square and rectangular tubing shall not exceed three times the corner radius.
