| Combined with ShaGang group co.,LTD."IF the steel production process development"project,through the thermal simulation experiment,hot rolling laboratory experiment and field production debugging and research,final determine the production process of the niobium-titanium composite gapless atomic steel.the main content of the paper includes:(1)Through the study of the influence of elements such as C and N,Nb and Ti,Mn and Si,S and O on the deep impact of the IF steel,the production components of the production can be quantified in combination with the production conditions of sand steel.The field production has successfully developed an IF steel that meets the requirements of the project,with the RH(the experimental furnace no oxygen)and the#1 continuous casting machine,with the KR desulphurization,180 tons of top-bottom converter,and the RH with the top blowing process.(2)Using the Gleeble3800 heat simulator to analyze the influence of heating temperature,rolling rate and volume taking temperature on post-rolling tissue.By simulation under different temperature conditions in the design of the IF steel composition grain situation of Nb,Ti and other exudates in different deformation and deformation temperature and deformation rate,grain size under the circumstance of different crimp temperature and the effect on the properties of the final,select the best process is obtained.Determine the controlled rolling process of controlled cooling is adopted in the experiment the slab heating temperature for 1225±25 ?,heat preservation time of 2h,at the beginning of rolling start temperature for 1145±25 ?,precision rolling start temperature for 1050±20 ?,finishing temperature for 910±20?,the cold temperature for 900± 10 ? the cooling rate is greater than 20?/s,coiling temperature is 710±30?,after finally rolled organizations for the ferrite grain size is about 8.6.Successfully developed a hot-rolled coil,2?4 mm thickness specification plate.Via detecting experiment plant and plant trial production products to yield strength less than 190MPa,tensile strength is less than 350 MPa,the elongation is more than 50%.By the SEM analysis,the main deposition of TiN and TiC/Ti(C,N),TiS,Ti4S2C2,precipitates distribution is more dispersion,the relatively small number of precipitates,and basic exist in large size particles,its size is generally between 0.05?2 microns.(3)The trial production of hot rolled IF steel cold rolling,the cold rolling process for acid pickling,cold rolling deformation of 75.75%,alkaline cleaning oil removal,740? 8.5h,2 times full hydrogen bell type annealing is flat and level.In the end,the cold rolled IF steel volume with a thickness of 0.97mm was obtained,and its deep punching performance reached the performance requirements of GB/T 5213-2008,which reached the level of DC06.(4)Analysis of cold rolled IF steel finished product performance testing,the results show that the IF steel deep drawing performance is very excellent,on behalf of the deep drawing performance r90 reached 2.66,the highest value of n up to 0.28,extending rate of 51%,the value of cup drawing,the EI?11.48,Ze?2.64%,reached GB/T 5213-2001 Chinese super deep drawing steel used for stamping performance requirements of the most complex parts. |
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