The Difference Between Cold Drawn Pipe And Ordinary Seamless Steel Pipe

1. Cold-drawn tubes will cause the material lattice dislocations and other micro-defects and increase the surface roughness, and induce martensite transformation and carbide precipitation. For example, austenitic steel exhibits an increase in magnetic properties after cold working.

2. The dislocation or phase change of the material lattice occurs on the surface, which will become the starting point of local corrosion such as pitting corrosion. This phenomenon of cold drawn pipes will have a direct adverse effect when the degree of deformation reaches 20% minus the section rate.

3. The cold-drawn pipe will leave residual stress in the material after cold processing, which is extremely unfavorable to the stress corrosion cracking resistance of the material. Any degree of cold working of the cold drawn steel pipe will greatly increase the SCC sensitivity of the cold drawn steel pipe material.

4. The degree of cold working also has an adverse effect on the high temperature durability of cold drawn steel pipes. Generally, the higher the working temperature or the higher the fracture life of cold drawn pipes, the lower the allowable degree of cold working.

The difference between cold drawn pipe and ordinary seamless steel pipe:

1. The main feature of ordinary seamless steel pipes is that they have no welded seams and can withstand greater pressure. The product can be very rough cast or cold drawn parts.

2. Cold drawn pipes are products that have appeared in recent years, mainly because the inner hole and outer wall dimensions have strict tolerances and roughness.

Cold-drawn tube pickling is to soak the carrier with 6mol/L hydrochloric acid for 2 hours or heat and soak with concentrated hydrochloric acid for 30 minutes, filter, wash with water to neutrality, and dry. Pickling can remove iron, aluminum, calcium, magnesium and other impurities on the surface, but not silanol groups. The pickling carrier is suitable for analyzing acidic samples.

Degrease and rust the surface of precision seamless steel pipes to prepare for the next process. In the production process, the pickling process is to remove the surface oxide scale, then go through lubrication treatment, and then carry out deep drawing processing.

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