The successful production of extra thick S690QL cev

The quality of carbon steel is distinguished by the amount of sulfur (s) and phosphorus (P) in the steel. When the S690QL cev sulfur content in carbon steel is not more than 0.050% and the phosphorus content is not more than 0.045%, it is ordinary carbon steel; when the sulfur content and phosphorus content in carbon steel are less than 0.040%, it is high-quality carbon steel; when the S690QL cev sulfur content in carbon steel is less than 0.030% and the phosphorus content is less than 0.035%, it is high-quality carbon steel.

The production method of seamless steel pipe can be roughly divided into cross rolling method (menesmann method) and extrusion method. The cross rolling method (menesmann method) is to pierce the tube blank with the cross roll first, and then extend it with the rolling mill. This method is fast in production, but requires high machinability of tube blank. It is mainly suitable for producing carbon steel and low alloy steel tube, S690QL cev tube.

Titanium microalloying is an element of S690QL cev strengthening complex with carbon and nitrogen. The addition of micro amount of titanium in the steel can fix almost all nitrogen and part carbon in the steel, so as to eliminate the strain aging phenomenon and improve the aging impact performance of the steel. At the same time, it can refine the grains and change the morphology of the compounds. According to the atomic weight ratio of Ti and N in S690QL cev tin formula (Ti = 3.4n), the content of Ti in steel should be controlled between 0.015 and 0.025%. Generally, the amount of ferrotitanium added to each ton of steel is 1kg.

Many people will mix strip steel and steel plate together, which can usually be distinguished from the following points. First of all, the thickness of the steel plate is much thicker, and the thinner the strip steel is required, the better. Secondly, in appearance, the steel strip can be crimped and the steel plate is too thick to bend, even if it is bent, it is difficult to recover, because it is easy to break if it is bent too much. Thirdly, the strength of S690QL cev, steel plate is higher than that of strip steel. The steel plate is suitable for construction engineering, while strip steel is only suitable for processing into hardware products.