[0005] Chinese patent CN200680006324.X discloses a "steel with excellent sulfuric acid dew point corrosion resistance", which is cold-rolled steel. In the laboratory, a 50kg steel ingot is smelted in a vacuum smelting furnace, and then hot-rolled, cold-rolled and annealed to obtain a coil; China Patent CN201010116893.8 discloses a "Sulfuric Acid Dew Point Corrosion Resistant Steel KNS and Its Rolling Method", which involves a 4mm thin gauge steel coil, and does not give the specific properties of the steel and sulfuric acid dew point corrosion resistance; Chinese patent CN201110268721.7 A "sulfuric acid dew point corrosion-resistant steel with tensile strength ≥ 800MPa and its preparation method" is disclosed, which involves a coil whose composition design does not add Nb and Sb elements, and the steel coil produced has a low elongation and does not give impact performance, only the dew point corrosion resistance of sulfuric acid at 20°C and 20% sulfuric acid is given; Chinese patent CN201310568537.3 discloses a "wear-resistant sulfuric acid dew point corrosion-resistant hot continuous rolling steel and its manufacturing method", which involves a wear-resistant Sulfuric acid dew-point corrosion-resistant hot-rolled steel strip (coil) and its manufacturing method, using a hot-tandem rolling mill to produce a hot-rolled steel strip (coil) that meets wear resistance and sulfuric acid dew-point corrosion resistance, and does not add Cr in its composition design , Ni element, only the acid resistance performance under the condition of 30°C and 20% sulfuric acid is given, and its mechanical properties are not given; China CN201310595866.7 discloses a "low-cost low-alloy steel for sulfuric acid dew point corrosion resistance and its production process and use", involving a round steel produced by hot continuous rolling process, its composition design adopts low carbon, low manganese, high chromium, no niobium element is added, the strength level is Q320-340, and only 70 ℃, 50% sulfuric acid is given Acid resistance under conditions
The appearance and appearance of the steel products of the above five patents are thin gauge coils / steel strips and round steel respectively. It is difficult to make wide and thick coils, and its application is relatively narrow; its production process is the same as the "thick gauge Q420 grade" of this application High temperature sulfuric acid dew point corrosion resistance of hot-rolled steel sheets is quite different, and the composition design is also different
[0006] Chinese patent CN200910187512.2 discloses a "low-alloy sulfuric acid dew-point corrosion-resistant steel plate and its manufacturing method". Bi element is added to its composition design, and Sb element is not added. The implementation example is an 80kg steel ingot completed in the laboratory Its smelting and rolling, its strength is Q370-420 level, and only gives the acid resistance under the condition of 70°C and 50% sulfuric acid; Chinese patent CN 201010211471.9 discloses a kind of "a kind of rare earth low alloy steel resistant to high temperature sulfuric acid dew point corrosion" , adding RE (La, Ce) in alloy design, without adding Sb element, but did not give the production process, appearance and mechanical properties of the product; Chinese patent CN 201110418531.9 discloses "a Zr-containing sulfuric acid dew point corrosion resistant steel plate and its manufacturing method", its alloy design has added rare Zr elements, and its implementation examples have been smelted and rolled in the laboratory, and only the dew point corrosion resistance of sulfuric acid at 20°C and 20% sulfuric acid is given
[0008] Chinese patent application CN 201510272614.X announced a "high-performance sulfuric acid dew point resistant steel plate and its manufacturing method", but its composition design and production process are quite different from this patent application: the alloy composition design uses low Carbon, high copper, high nickel, high chromium, the alloy cost is relatively high, and the controlled rolling + tempering process is used to produce, increasing the tempering process will inevitably increase the production cost; the strength and low temperature impact energy of the steel plate with a thickness specification > 30mm are both It is relatively low, and it only gives the relative corrosion rate, and does not give the corrosion conditions and comparative steel types
[0009] Chinese patent application CN 201510870140.9 discloses a "low-cost Nb-free thin-gauge sulfuric acid dew-point corrosion-resistant steel and its production method", which only involves thin-gauge 8-12mm steel plates, adding V elements in the composition design, and not adding Nb element; and its strength is low, no impact performance and sulfuric acid dew point corrosion resistance are given
[0011] Chinese patent application CN 201410551555.5 discloses a "sulfuric acid dew point corrosion-resistant steel plate and its manufacturing method". This patent application does not add Sb element in alloy design, but adds V element, and adopts relatively low carbon and high Manganese; its thickness can only reach a maximum of 32mm, and only gives the corrosion resistance at a temperature of 70°C and 50% sulfuric acid
[0012] Among the steel products in the prior art, there is no high-grade sulfuric acid dew point corrosion resistant steel plate with low cost, comprehensive mechanical properties, excellent sulfuric acid dew point corrosion resistance, welding performance, and formability under high temperature and high pressure conditions.