Abstract: Implant tests were conducted on l5MnVN steel using Ar+20%CO₂ gas shielded welding process.The test results have shown that when the welding heat input is in the range of l5~40kJ/cm the critical stresses of the implant specimen are all above the yielding strength of l5MnVN steel and are higher than that of the specimen welded with J507 and J557MoV welding electrodes.A welding heat input of 20~30kJ/cm should be chosen so as to make the heat-affected zone of 15MuVN steel have the optimum microstructure and good resistance to cracking.