Microstructure And Mechanical Properties Of Hot-orlled High Alumium304and316L Steels And Effect Of Alumium On Action Mechanism

In order to solve the problem of poor uniform corrosion resistance andintergranular corrosion of316L steel, our group developed the316L steel with highaluminum. Research shows that as-cast high-aluminum316L alloy had excellentcorrosion resistance, while the mechanical properties did not decreased. Based on this,this research attempt to hot-roll the high-aluminum304、316L ingots to the plates, andthen investigate the microstructure, mechanical properties, corrosion resistance,weldability of the high-aluminum304、316L plates. The aim of this research is that tomake the high-aluminum304、316L plates have excellent corrosion resistance, whiletheir mechanical properties decrease little.This research used the304and316L as the base metal, and the weight percentageof2and4%Al was added in these alloys. The steels with2and4wt.%Al were meltedin vacuum arc furnace and solidified in water-cooling-molds. And then the ingots werebreak-down rolling. The microstructure and mechanical properties of steel afterhot-rolling were investigated. The results showed that the matrix of the steels was γ-Fephase when content of Al was not more than2wt.%. After hot-rolling, Al elementprecipitated from matrix and combined with carbon to form Al4C3phases, and α-Fephase has appeared when304、316L hot-rolled plates with4wt.%aluminum.Room temperature mechanical properties of304、316L hot-rolled plates with2,4wt.%aluminum after solution treatment was tested. The results showed that thestrength of304plates decreased slightly first and then increased, and the plasticitydecreased with the increase of aluminum content. The316L plates’ strength increasedobviously and plasticity decreased slight with increasing of aluminum content.The uniform corrosion resistance of316L steel and the intergranular corrosion of304and316L steel were studied. The results showed that316L plates with2wt.%and4wt.%aluminum had the lowest uniform corrosion rate, and plate with2wt.%had thelowest intergranular corrosion rate. The304plates with4wt.%aluminum had the bestresistant of intergranular corrosion.Weldability of304plates with4wt.%aluminum and316L plates with2wt.%aluminum were tested. The results showed that high-aluminum304、316L hadexcellent weld ability.