Prior to October 18,2009, the control of chemical composition in front of the furnace in the foundry workshop was completed once by hand, and the process control was based on experience. Since the introduction of spectrometer on October 18,2009, chemical composition adjustment in front of the furnace is divided into two tests: initial sample and duplicate sample, which increases the controllability of chemical composition control of Centrifugal

Roller. But in 2010, the chemical composition is still unstable. The average qualified rate of centrifugal roller is only 93.26% , which brings hidden trouble to the quality of roller.
      At the beginning of 2011, the technical supervisor organized the test group to analyzethe poor control of the composition in 2010, and the following problems existed:
      1, operators believe that before a manual test can produce molten iron, not to mention now more advanced spectrometer, waiting is a waste of time and cost. Sometimes the results of the resampling have not come out, began to cast molten iron, unstable composition.
      2. The sampler takes samples without standard in front of the furnace or without even safety of molten iron when taking samples.
      3, take good spectral sample after grinding, there are grinding too shallow and pores, slag not polished or cracks, etc. will have a certain impact on the composition.
      4. The Spectrometer is easy to appear abnormal in the condition of power cut or in the process of changing Argon Gas, and the test is not accurate.
      5. The content of silicon and carbon is easy to be unstable in the process of controlling the component of centrifugal roller. The higher the temperature of hot metal is, the more serious the carbon loss will be, and the silicon content will be unstable after inoculation of infinite cold hard roller.
  After analysis and discussion and make corresponding corrective measures:
      1, the technical supervisor believes that waiting may be a waste of time and cost from an objective point of view, but the influence and waste caused by the unstable use of roller due to the unstable composition are even greater, at the beginning of 2011, we must carry out two tests after the water to ensure the quality of stability, but also to coordinate the work of the various teams to reduce the waiting time.
      2. Strictly operate according to the sampling standard of spectrometer drawn up by chief engineer Li Jiyu.
      3. The Tester must be in the first to the second test and add the alloy to determine that there is an abnormal request for the third resampling confirmation.
      4. The abnormal spectrometer has been fed back to the quality control department, and the department has been improved accordingly, which has brought some help to the furnace front control. But the tester also needs to be careful in judging each chemical spectrum sample.
      5. For the control of silicon in the infinitely cold-hardened Centrifugal Roller, the tester should not only judge the composition of the tested silicon, but also have a better choice for the silicon inoculation. The silicon-iron without impurity or with less impurity should be chosen as the inoculant, this improves the accuracy of the silicon after

implantation. Carbon Control of the number of hot metal, hot metal placed in the furnace waiting time for a long time in the middle of pouring a few samples, if there is a problem can be corrected in time. For the control of Silicon in Bainite and spheroidal graphite centrifugal roller, the tester should judge the amount and composition of iron chipping, and measure the final silicon content as far as possible. Control of carbon because high temperature spheroidized carbon is burned seriously, so the carbon in front of the furnace should be adjusted to the upper limit and given a certain amount of carbon loss. In the meantime, the temperature of molten iron should be high or low, and the length of time in the road should be judged to add how much carbon, if the storage time is longer, the carbon can be added after sampling and analysis.
        In 2011, the chemical composition of the centrifugal rolls has been setting new records for three consecutive months from January to March with the joint efforts of the technical staff in the casting workshop. 96.2% in January, 98.02% in February, 99.25% in March, up 4.83 percentage points from 93.27% in 2010 to 98.10% in November 2011, up 5.18% to make a small contribution to the strong brands. Steel machine, straightening machine, cold rolling