Niobium is one of the most important alloying elements in steel. By adding a very small amount of niobium into steel, the strength, mechanical and welding properties and corrosion resistance of steel can be greatly improved. Niobium steel is widely used in many sectors such as Bridges, construction, heavy machinery, ships, rail beams, automobiles, tractors, internal combustion engines, steam turbines, drilling equipment, large boilers, cutting tools, industrial molds and so on.
There are 24 kinds of niobium-bearing steels that have been brought into the standard or identified for production in China, and there are a total of 35 kinds of niobium steels that have been tried in batch production. Its development went through a tortuous process, and it was on the rise from the mid-1960s to the early 1970s. In the mid to late 1970s it was at a low ebb; It has been on the rise since the early 1980s. Up to now, new progress has been made in scientific research, production and application of niobium steel.
The amount of niobium used in low-alloy high-strength steel is the largest, accounting for more than 80% of niobium used in steel industry, generally containing niobium 0.02-0.05%. Adding trace niobium to form stable carbides and carbonitrides, which can refine grain and precipitate out niobium carbide, can also improve steel strength (generally increase 25-30% and creep resistance). For example, the 10MnNb steel plate produced by Shanghai No.1 Steel Plant is used for the construction of 3,000-ton dredger with good performance, meeting the requirements of ZCD36 Marine steel plate, and is prepared for the construction of 3,000-ton oil tanker and 10,000-ton sea vessel. Shanghai Heavy Duty truck Factory USES 10MnNb steel plate as girder of 4 ton crane truck, its stamping performance is excellent, and it continues to be used in 10 ton and 15 ton crane truck. In terms of oil and natural gas transmission pipelines, 10MnNb steel and 10MnVNb steel reached X56 and X60 in the United States. The level of steel is being organized and applied. Low carbon manganese-niobium steel plate may be used as boiler steel to improve its formability and weldability, and is also widely applied in organization.
All steels are of high alloy except low alloy steels, which contain more niobium than low alloy steels, but less than low alloy steels. The additive of high alloy steels containing niobium is usually the metal niobium bar or the iron niobium 50-70% niobium. High-alloy steels containing niobium include stainless steel, heat resistant steel, corrosion resistant steel, etc. For example, lCrllCobMnVNbBN steel has been used in 8-11 class turbine disks and 9-12 class blades of aircraft engines. OCr13Si4NbRe steel is resistant to oxidizable medium corrosion and has been used in valves and pump bodies of concentrated nitric acid production equipment. Niobium stainless steel electrode is mainly ob137 and other grades (electrode and flux are Nb2%), in recent years, the amount of increasing.
