Former factory manufactures cold drawn seamless pipes have to do some tests, such as the composition of seamless steel goods, precision seamless steel pipe product specifications, and pressure testing, flaw detection and other aspects of the spectrometer detection. Like seamless steel tubes, cold drawn seamless commodity enterprise applications in the acquisition of seamless pipe, cold drawn seamless tube of goods but also to do some simple project acceptance, seamless steel models standard query, cold drawn seamless tube specifications model verification, accurate measurement of precision seamless tube specifications and verification acceptance of seamless steel tubes total.
of the water content of harmful metals AsSnSbBiPb vapor and the like NHO clear that the provisions to enhance the purity of the symmetry and the steel component of steel, non-metallic materials to reduce debris finishing reference tube and improve their situation around, often chosen for molten steel refining equipment to carry out scouring, and even the choice of electroslag remelting furnace to carry refined to finish tube.
2. Specification precision and appearance design
The geometric specifications of seamless steel pipe include the diameter, wall thickness, ovality, length, bending degree, inner hole inclination, weld angle and blunt edge of seamless steel pipe, cross section specifications of foreign friend seamless steel pipe, etc.
3. Process performance
Cold drawn seamless pipe The specification requires the "surface finish" of seamless pipe. The common defects are: crack, hairline, internal fold, external fold, rolling break, internal straight path, external straight path, delamination, scab, dent, convex hull, pockmark (surface), scratch (scratch), internal spiral path, external spiral path, green line, concave correction, roller printing, etc. Among them, the risk defects of crack, internal fold, external fold, rolling break, delamination, scab, dent, convex hull alignment; the general defects of seamless steel pipe are the surface, blue line, scratch, slight internal and external straight track, slight internal and external spiral, concave alignment and roll printing.
4. Physical characteristics
It includes the physical properties at room temperature and at a certain temperature (thermal strength and ultra-low temperature characteristics) and corrosion resistance (such as oxidation resistance, water corrosion resistance, strong acid and alkali resistance, etc.) generally, the composition, mechanism characteristics, purity of steel and the heat treatment method of steel. In some cases, the cold rolling temperature and deformation level of seamless steel tube will also cause harm to the characteristics of seamless steel tube.5.
comprising a seamless steel pipe flaring, flat extrusion, curling, bending, welding, and welding characteristics cyclamate.
6. Alloy composition
It includes high-power mechanism and low-power mechanism of seamless steel pipe.
Characteristics of precision seamless pipe
1. High precision, saving the loss of machining materials.
2. It has many specifications and wide application range.
3. Cold rolled products have high precision, good surface quality and good straightness.
4. The inner diameter of steel pipe can be made into hexagon.
5. The performance of steel pipe is superior, and the metal is relatively dense. Compared with solid steel such as round steel, seamless steel tube is a kind of economic section steel, which is widely used in manufacturing structural parts and mechanical parts.
Main uses of cold drawn seamless pipe:
Cold drawn seamless pipe is widely used. The general purpose cold drawn seamless pipe is rolled by common carbon structural steel, low alloy structural steel or alloy structural steel, with the largest output. It is mainly used as the pipe or structural part for conveying fluid.
Maintenance of cold drawn seamless pipe:
In the passivation film of cold drawn seamless pipe, the parts with weak corrosion resistance form pitting corrosion reaction due to self-excited reaction, and form small holes. In addition, the chloride ions are close to each other, forming strong corrosive solution, accelerating the speed of corrosion reaction. There are also intergranular corrosion cracking in stainless steel, all of which destroy the passivation film on the surface of stainless steel plate. Therefore, the surface of cold drawn seamless pipe must be cleaned and maintained regularly to keep its gorgeous surface and extend its service life.
Surface treatment process of precision seamless pipe:
1. Degreasing of precision seamless pipe
Before passivation and pickling treatment, the surface of precision seamless pipe must be degreased and degreased, and further components must be welded in degreasing treatment line to avoid carbon in high temperature.
2. Passivation of precision seamless pipe
Passivation process can only deal with precision steel pipe and stainless iron. The primary purpose of passivation is to avoid surface oxidation and corrosion of precision seamless pipe.
3. Pickling of precision seamless pipe
The purpose of pickling treatment of precision seamless pipe is to remove the oxide skin on the surface of precision seamless pipe after high temperature welding, heat treatment or heat processing. It can also eliminate the pollution of steel or iron or steel particles corroded by red rust. But pay attention to clean the acid on the surface of precision seamless pipe in time after pickling, otherwise the surface of steel pipe will start to rust soon. This results in a decrease in the corrosion resistance of the steel pipe surface below.