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目前我国国产汽车活塞环使用寿命较短,与国外相比较存在相当差距。国外汽车活塞使用寿命达30万公里以上,而我国先进水平是10万公里~[1],对不镀铬的活塞环寿命仅5～6万公里。使用寿命短的原因,除了磨损和折断外,性质的热稳定性差是一个很重要的因素。因此,提高材质的耐磨性和热稳定性是提高活塞环寿命的关键。为此,我们研制了珠光体铌合金铸铁活塞环。 铌合金铸铁活塞环具有良好的耐热耐磨性能。主要是由于铌对铁素体的固溶强化作用而强化了铸铁基体。铌对碳氮有很强的亲和力,在铸铁中呈δ-NbC,δ-Nb（C、N）析出,呈面心立方晶格。它们的熔点很高（NbC的熔点3500℃以上,NbN熔点25730℃）,并均匀分布于基体之中,因而高温性能稳定,耐热性好。碳氨化铌的颗粒大小一般为3～7μ。在加铌量0.3％左右时,每平方毫米面积上析出100个以上,其显微硬度达HV2000～
At present, China’s domestic car piston ring life is shorter, compared with foreign countries there is a considerable gap. Foreign car piston life of up to 30 million kilometers, while China’s advanced level is 100,000 km ~ [1], on the non-chrome-plated piston ring life of only 5 to 60,000 km. Short life reasons, in addition to wear and tear, the nature of the poor thermal stability is a very important factor. Therefore, improving the wear resistance and thermal stability of the material is the key to improve the life of the piston ring. To this end, we developed a pearlite niobium cast iron piston ring. Niobium alloy cast iron piston ring has good heat resistance and wear resistance. Mainly due to the solid solution strengthening effect of niobium on the ferrite and strengthen the cast iron matrix. Niobium has a strong affinity for carbon and nitrogen, and exhibits δ-NbC and δ-Nb (C, N) precipitation in cast iron with a face-centered cubic lattice. Their high melting point (NbC melting point above 3500 ℃, NbN melting point 25730 ℃), and evenly distributed in the matrix, which high-temperature performance and stability, good heat resistance. Carbonitride niobium particle size is generally 3 ~ 7μ. Niobium in the amount of about 0.3%, the precipitation of more than 100 per square millimeter area, the microhardness of HV2000 ~