| As transmission line towards long distance,large capacity,high voltage direction and extension,the traditional Al-B wire cannot meet the strict requirements of aluminum wire,which put forward on the performance of large span and ultra-high voltage transmission,so it is eager to develop new aluminum wires with better comprehensive performance.The electrical round aluminum rods are used as the blank of cables and wires.The quality of electrical round aluminum rod directly influences the merits of the aluminum wire.In this article,the research object of experiments is Al electrical round aluminum rod boronized with 0.02% B.Firstly,the composition optimization was carried out by orthogonal test with 5 factors and 4 levels of on the original Al-B electrical pole;Second,the effect of solid solution and aging treatment on the properties of samples were studied after the composition optimization;Then,combined with better solid solution + aging process,different thermomechanical treatment was conducted on the sample;Finally,different deformation drawing processing was proceeded on specimens with better comprehensive properties after thermomechanical treatment.The results were shown as follow.1.when the composition of sample is Al-0.7% Cu-0.2% Y La Ce-0.3%-0.3%,the as-cast alloy electrician round rod has a better comprehensive performance,the electrical conductivity,tensile strength and elongation can reach to 56.00% IACS,100 MPa and 15%,respectively.2.Solid solution + aging treatment was carried out on the as-cast sample,the samples were treated at 510? for 6 h,cooled in a concentration of 13% PAG medium,and then aged at 190 ? for 10 h.The sample was of good comprehensive performance,the tensile strength of samples was 125 MPa,elongation was 18% and electrical conductivity was 57.5% IACS.This is mainly due to the hardening alloy elements fully dissolved into matrix after quenching treatment,the structure of sample was uniform,only a small amount of fine precipitates existed in grain boundary,after aging treatment,a lot of alloy elements precipitated distributed in the grain and grain boundary dispersively,improving the strength of specimens.3.Different thermomechanical treatment was proceeded on optimal solution aging as-cast sample,after “solid solution + pre-deformation + aging + retransformation”thermomechanical treatment,sample has better comprehensive performance.This is mainly because prestressing could accelerate the subsequent aging treatment process and form more exsolution products distributed in the matrix uniformly.The re-deformation refined the grain,it also made the sample have more deformation energy storage,thus making the tensile strength of specimen reach to 202 MPa.Besides,the precipitation of second phase made the conductivity and elongation reach to 59.11% IACS and 8%,respectively.4.The drawing process of different deformation was conducted on the specimens with better thermomechanical treatment,the result indicated that with the increase of deformation,the electrical conductivity decreased slightly,but tensile strength increased greatly.When the deformation was 77%,the tensile strength of samples was269 MPa,extension rate was 3% and the electrical conductivity was 57.56% IACS. |
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