Q690C low-alloy high-strength steel plate is a low-carbon, low-alloy, high-strength engineering structural steel. In Q690C steel, Mn and Mo are the main alloying elements, and some are supplemented with V, Cr, Ni, B, etc. to improve the hardenability of the steel through the addition of alloying elements, thereby further improving the strength and toughness of the steel.
The content of main alloying elements such as C, Si and Mn in low alloy high strength steel is 5% lower. The 690MPa low-alloy high-strength steel adopts controlled rolling and controlled cooling technology, and the rolled steel plate is subjected to the modulation treatment of quenching and tempering, which realizes the design of lower carbon equivalent and low alloy composition, and has a higher Strength and toughness, excellent comprehensive mechanical properties. Its matrix structure is mainly bainite and a small amount of martensite.
As the main equipment for offshore oil and gas development, offshore drilling platforms are gradually developing into the deep sea, and the thickness of steel used for platforms is gradually increasing, and the strength is also getting stronger. As the main bearing structure of offshore platforms, the welding quality of pile legs will directly affect the safety and use effect of platform lifting. The rack plate on the leg is the core of the platform lifting, so the butt welding of the leg rack is the focus and key of the lifting offshore drilling platform.
In view of the excellent performance of Q690C low-alloy high-strength steel and the current large-scale equipment to reduce their own weight and meet the strength level requirements, low-alloy high-strength steel is more and more used in the manufacture of large-scale structures such as drilling platforms, nuclear power equipment, and crane jibs. Come.
