The seamless steel pipe has a hollow section, which is widely used to transport fluid, such as oil, natural gas, coal gas and water. Compared with solid steel like round steel, the steel pipe has the same bending, torsion strength but lighter weight. It is a kind of economic section steel, which is widely used in the manufacture of structural parts and mechanical parts, such as petroleum drill pipes, automobile transmission shafts, bicycle frames and steel scaffolds in construction.
The seamless steel pipe is a kind of long steel with hollow section and no seam around. It is made of steel ingot or solid tube blank by piercing, and then by hot rolling, cold rolling or cold drawing. The following introductions are the relevant knowledge of seamless steel pipes.
Applications of seamless steel pipes
1. Seamless steel pipe is widely used. The general seamless steel pipe is rolled by common carbon structural steel, low alloy structural steel or alloy structural steel with the largest output. They are mainly used as pipes or structural parts for conveying fluid.
2. It can be divided into three types according to different uses:
a. It can be supplied according to chemical composition and mechanical properties.
b. It can be supplied by only the mechanical properties.
c. It can be supplied as per the hydrostatic test. If the steel pipe is supplied according to the above class a and class b, it is used to bear liquid pressure, and the hydrostatic test should also be conducted.
3. There are many kinds of seamless pipes for special applications, such as boiler seamless pipes, geological seamless pipes and petroleum seamless pipes.
Identification of seamless steel pipes
1. The fake seamless steel pipe is easy to scratch because the equipment of the fake seamless steel pipe manufacturer is poorly equipped. There will be burrs produced to scratch the steel surface. The deep scratches reduce the strength of steel.
2. The fake seamless steel pipe has no metallic luster and it is light red.
3. The transverse reinforcement of the fake seamless steel pipe is thin and low, and the phenomenon of insufficient filling often occurs. The reason is that in order to achieve large negative tolerance, the reduction of the first few passes of the finished product is too large. The iron mold is too small. And the pass is not fully filled.
4. The cross section of the fake seamless steel pipe is oval, because the reduction of the first two rolls of the finished product is too large in order to save materials. The strength of this kind of seamless steel pipes is greatly reduced. It does not meet the standard of the overall size of seamless steel pipes.
5. The composition of high-quality seamless steel pipe is uniform. The tonnage of cold shear is high, and the end face of the cutting head is smooth and neat. However, due to the poor material quality, the phenomenon of meat falling often occurs at the end face of the cutting head of fake and inferior seamless steel pipes, that is, uneven and no metallic luster.
6. The material of fake seamless steel pipes contains many impurities. The density of the steel is small, and the size is seriously out of tolerance, so it can be weighed and checked without a vernier caliper. Generally speaking, the whole weighing effect will be better.