1, high strength tempered structural steel. Has high strength and toughness, high hardenability, cold deformation plasticity medium, good cutting performance. There is a tendency to temper brittleness, transverse impact toughness is poor. Welding performance is good, but the thickness is greater than 3mm, should be preheated to 150 ℃, after welding heat treatment. General use after tempering;
2, heat-treated with good overall mechanical properties, high strength, adequate toughness, hardenability, weldability (preheating before welding), machining and forming are better, but low corrosion resistance and oxidation resistance, generally low-temperature tempering or isothermal quenching after use;
3, low-alloy high-strength steel is the most significant feature of high strength. In the hot-rolled or normalized state, low-alloy high-strength steel is generally higher than the corresponding carbon engineering structural steel strength can be 30% to 50%. Thus, it can withstand larger loads. Engineering structures are generally large or giant for more, the weight of the component itself often becomes an important part of the load, structural materials to improve the strength at the same time can significantly reduce the weight of the component and its ability to withstand other loads to further improve. Not only that, this good effect also greatly improves the compactness of engineering components so that its reliability is further improved, while reducing the consumption of raw materials, reducing costs and saving resources.
