Research On Improving The Production Process Of 300 Series Stainless Steel Wires Based On Six Sigma Management Method

Dongbei Special Steel Group CO.,LTD., one of the leading enterprises in China, mainly produce the stainless steel, automobile steel, die steel, bearing steel, anti-high temperature alloy, high strength steel etc.As the representative products, the 300 series stainless steel wires is reported by a customer that it has very high tensile strength and accidents of breaking.Therefore, the standard product that is made of the 300 series stainless steel may exists the quality problem with crazing.The research is aiming at solving the crazing problem of the 300 Ni-stainless steel products at the cold processing condition.Based on the management principle of SIX SIGMA and the design of experiments, the management and technology problems in the producting procedures of metallurgy, rolling, heat treatment are detected.The research will acquire the finally reasonable manufacturing plan to reduce the fluctuation of mechanical properties and improve the quality of products.The research is concluded the following results:The project adopts the methods of flow charts, causal matrix, and FMEA etc, to exclude the influence factors that may work on the influence factors. It is finally founded that the influence factors are solution temperature, soaking time and the content of N.By the analysis of the regression, it is also found that it is necessary to strictly control the content of Cr, however, as to the control of the content of N, it only needs to follow the filed operation regulation.The regression relationship between the tensile strength and the processing factors is approached by the design of experiments to provide the theoretical basis to the researchers.The project revised the 304B technical processing based on the critical requirement. Based on the inspection results of crystalline grain, when the grains has no difference and the grains at the border area and at central area has no difference at the temperature 1090? and temperature keeping time less than 5 mins, the materials will get the 100% solid solution critical value.It is proven by the filed verification, the tensile strength of the steel has the 100% yield percentage and successfully satisfies the requirements of the customers.By the above research, the research solve the problem that the 304B Ni stainless steel has the unreasonable tensile strength. It will improve the quality of the product and enlarge the market proportion.