Study On Microstructure And Performance Of Roll Casting Submerged-arc Surfacing Layer

The continuous casting roll is the core part of continuous casting equipment, the use to the roll directly impact on the performance of continuous casting equipment operating rate, the costs of steel slab and the quality. After used a period of time, besides has the roller body bending strain, the surface of rolls present crack, oxidative corrosion, attrition damage. Using surfacing process to repair the roll, not only may enhance the continuous casting roller's service life, but also reduce costs and the consumption of roller, and be able to improve the continuous casting equipment operating rate and product quality. So, the continuous casting roll repairing is always a meaningful research project in the metallurgical industry.In the testing, use microscope, Rockwell hardness tester, wear test equipment to analyze the microstructure, hardness, chemical composition, wear resistance about surfacing layer, and carry on the discussion about what problems in the process welding possibly appear and how to prevent.Conclusions of the paper is as follows:1. When 21CrMoV5.11 steel roll are welded with the heat input of 19KJ/cm, 21KJ/cm, 27KJ/cm, the rate of dilution of the bottom of the welding metal is no higher than 50%, they are 27%, 30%and 44%; when the submerged arc welding are played on 42CrMo steel roll with YJ101N-S wire, the work layer welding metal content nitrogen about 0.064%, and non-dilution in the work layer.2. When submerged arc welding carried on with specific welding materials, the organization characteristic of deposited metal of the 21CrMoV5.11 steel and the 42CrMo steel continuous casting roller is: martensitic substrate distributed a certain amount of ferrite, welding heat input increases, ferrite content slightly has increases.3. After submerged arc welding, the distribution of hardness is more even on each layer, the average hardness of the work layer welding metal of the 21CrMoV5.11 steel roll are 39.0HRC, 39.5HRC, 38.6HRC. Welding heat input on the changes do not affect the value of hardness; the hardness of work layer welding metal of 42CrMo steel roll with larger diameter is higher, with an average of 48.9HRC.4. when welding heat input for 21kJ/cm time, wear resistance of work layer welding metal of 21CrMoV5.11 steel roll is better, the relatively wear coefficient is 0.6880; wear resistance of work layer welding metal of 42CrMo steel roll with the diameter ofΦ150mm is better, the relatively wear coefficient is 0.5912.