Differential Thermal Analysis (DTA) and high frequency )HF( coil measurement were carried out in present work in order to measure the liquidus temperature of some austenitic and duplex stainless steel samples made by different steel companies in Sweden. A good agreement between the measured and thermal calculated values using Thermo-Calc software (Appendix 1) was found. The liquidus model used 1986 shows a lower value for most of these alloys. When the nitrogen gas used as an inert gas, the nitrogen content increased in the alloys because of the increasing of nitrogen solubility at high temperature. On the other hand, the nitrogen content decreased in the alloys when the argon used as an inert atmosphere because of the different partial pressure of nitrogen between the liquid alloy and the atmosphere. This changing has an effect on the microstructure and liquidus values especially in high nitrogen content alloys.