| Tensile, fatigue, creep-fatigue, creep tests were conducted at R.T.∼600℃ to evaluate the effect of nitrogen on mechanical properties and the optimum nitrogen content for type 316L(N) stainless steel containing the different nitrogen content from 0.04% to 0.15%. Tensile strength decreased with temperature and increased with the addition of nitrogen but elongation was not decreased with the addition of nitrogen. Fatigue life was almost same up to 300℃ and decreased drastically at 600℃. Fatigue life increased with the addition of nitrogen but decreased at above 0.10% nitrogen content. Fatigue crack propagation increased with temperature, decreased with the addition of nitrogen, and increased at above 0.10% nitrogen content. The time to rupture for creep increased with the addition of nitrogen and saturated at above 0.10% nitrogen content. Minimum creep rate of creep decreased with the addition of nitrogen. Creep-fatigue life increased with the addition of nitrogen but decreased at above 0.10% nitrogen content. Mechanical properties were improved up to 0.10% nitrogen content but saturated or decreased at above 0.10% nitrogen content. The optimum nitrogen content for the high temperature mechanical properties of type 316L(N) stainless steel was evaluated as 0.10% in the 0.02% carbon content. |
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