Study On The Factors Affecting The Microstructure And Properties Of GNiCr40Al3Ti Alloy

GNiCr40A13Ti alloy is using in high temperature and high magnetic field environment, it is a new kind of magnetic bearing material. After solid solution and aging treatment the hardness can reach more than 58HRC. Its higher alloy content, the forging of poor performance, addition of RE element can greatly enhance the performance of forging and refine the grain size of the alloy, Try an experiment on properties of alloy by electroslag remelting technology, through the observation of microstructure and performance, we can get the following conclusions:(1) GNiCr40A13Ti alloy after solid solution treatment, the composition of a-Cr phase and the matrix of austenite. The matrix hardness of alloy is depending the grain size, through the statistics of α-Cr particle size, the average is about 1.5μ m ～1.6μ m. Considering about the grain size, hardness and the number of α-Cr, the heat treatment temperature solution treatment of GNiCr40A13Ti alloy was 1180 ℃ ～1220 ℃, the heat treatment time was 40min～60min.(2) After aging treatment of GNiCr40A13Ti alloy is composition of α-Cr phase and the matrix of austenite and y’-phase, austenitic matrix is lamellar organization, as the reason for its change does not yet have in-depth study. The volume fraction of γ’-phase at around 2% by phase analysis,93% of the y’ -phase particle size 6.6nm or less, it is extremely important in a second phase strengthening means of GNi40Cr3Ti alloy, it can be giving additional strengthening intensity is about 1200MPa.(3) RE has a beneficial effect of GNiCr40A13Ti alloy. The most important thing is can greatly improve the thermoplastic of GNiCr40A13Ti alloy, upgrade from the original 100 ℃ range of malleable to 350 ℃, it can reduce the number of forging process recycled, reducing the cost of forging; secondly, to improve the uniformity of the organization, compared to the GNi40Al3Tialloy without RE, the uniformity of their organization is better, but also to reduce the grain size of alloy, finally, the inclusions of alloy has also been improved.(4) GNi40A13Ti alloy smelting by using ESR, in a certain decrease in the grain size and uniformity of grain size has also been some improvement. The hardness of the alloy after solution and aging did not affect. The electro slag remelting changed the chemical composition of the alloy, Reducing the content of Al and increasing Ti content resulted in reduced toughness GNiCr40A13Ti alloy.(5) To improve the alloy after aging unnotched impact toughness,to improve solution and aging temperatures.