| In order to study the influence of V, Cr addition to the low-carbon steel on microstructural transformation and mechanical properties , on the basis of the 0# steel for 26×92 C grade round link chains,five kind experimental steels with different V, Cr content had been prepared. Microstructure observation of experimental steels in different heat treatment processes have been carried out by optics microscope and SEM. The CCT curves of the experimental steels addition V(0.17%) was investigated by means of full automatic phase transformation tester of Formaster-IV. The mechanical property measurements in different conditions,the hardenability of the experimental steels and the tempered impact rupture appearance were conducted. In the last, contrasting with the 23MnNiCrMo54 steel imported from Japan, the wear-resistance performance of the experimental steels had also been studied.The test result indicated that the hardenability of the experimental steels enhanced with the addition of few alloying element V,Cr on the basis of the Micro alloy low-carbon SiMnMo steel, for the experimental steel addition 0.17%V ,the critical cooling rate of gaining all martensite drops from original 20℃/s to 10℃/s. The maximum full hardening diameters increased to 45～55mm ,and the martensite microstructure in center of the tested steel bar with diameter 34mm meanwhile. The hardness in center of the tested steel was above 45HRC. At the cooling rate ranging from 10℃/s to 5℃/s, it can obtain martensite and bainite structures. Under the condition of the cooling rate from 5℃/s to 2℃/s, the low-carbon lath bainite structures exhibited correspondingly, and the granular bainite exhibited correspondingly under the condition of lower than 2℃/s. The microstructures of the experimental steels normalized at 920℃is with complex microstructure of granular bainite and lath bainite, with the hardness of 26HRC～32HRC a little higher than that of requirement of shearing blanking the steel. Therefore, the content of alloy element should take the lower limit. Good comprehensive mechanical properties of the experimental steels, such as tensile strengthσb1339MPa～1556Mpa, elongationδ10%～14% and area reductionψ45%～57% can be achieved after 920℃quenching and 300℃,400℃tempering. In the same temperature tempered, the tensile strength of the experimental steels increased with the addition of few alloy element V,Cr, but with the content of alloy addition increased, tensile mechanical properties become unsensible and the impact energy decreased . The fracture surfaces of the steels composed of dimples and exhibited tough fracture characteristics. The wear resistance of the steels decreased with the increase of tempered temperature. The wear resistance increased with alloy element addition to the steels to some content.
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