The dynamic continuous cooling transformation（CCT）diagram and phase transformation rules of 510 MPa automobile beam steel,which is produced by a continuous casting of thin slab of FTSR technology in Tangshan Iron an...The dynamic continuous cooling transformation（CCT）diagram and phase transformation rules of 510 MPa automobile beam steel,which is produced by a continuous casting of thin slab of FTSR technology in Tangshan Iron and Steel Co.Ltd.,are researched by thermal simulation experiment.The microstructure characteristics of the beam steel under different test conditions are studied by means of optical microscope and scanning electron microscope.The test results show that the critical temperatures of phase transformation Ar3 and Ar1 will all decrease with the increase of the cooling rate.When the cooling rate is lower than 20 ℃·s-1,the ferrite and pearlite phase transformations are the main parts;when the cooling rate is higher than 20 ℃·s-1,the bainite phase appears.Moreover,the microstructures of 510 MPa automobile beam steel produced by FTSR technology are also studied,and the results are basically in accordance with the CCT diagram gained from the test.展开更多
590 MPa automobile beam steel strips are used mainly to manufacture the longitudinal beam of trucks.It’s welding properties are critical to the safety of truck.The microstructure and mechanical properties of welding ...590 MPa automobile beam steel strips are used mainly to manufacture the longitudinal beam of trucks.It’s welding properties are critical to the safety of truck.The microstructure and mechanical properties of welding joints processed by CO 2 arc welding with different welding parameters were studied.The results showed that the welding joints were weak when welding heat input were small and the non metal inclusions were found in the weld joints when welding heat input are big.The quality of the welding joints is good enough at 170A of the arc current and 24V of the arc voltage.Keeping the other welding parameters fixed,the incomplete fusion defect occurred in the welding joint with backward welding,but the quality of the welding joint is good with forward welding.展开更多
This paper has determined the compositions and hot rolling processes of the hot rolled beam steel plates with excellent surface oxide layer for automobiles by investigating the oxide layer forming principle and its in...This paper has determined the compositions and hot rolling processes of the hot rolled beam steel plates with excellent surface oxide layer for automobiles by investigating the oxide layer forming principle and its influence factors,and the feature of the steel oxide layer.The microstructure,mechanical properties,oxide layer shape and structural composition of the steel plates are analyzed by using metallographic structures examination,SEM analyzing,X-ray diffraction instrument and mechanical properties testing.The result shows that the trial hot rolled frame steel plates have an excellent oxide layer adhesion,the Fe 3 O 4 proportions is greater than 85% in the oxide layer,and the oxide layer thickness is less than or equal to 10μm.The product has been trial-manufactured more than 100 thousands ton,and used to stamp the beam parts of automobiles straightly in no pickling process.The oxide layer scarcely scales off from the steel plates,and the effect is remarkable.展开更多
基金Item Sponsored by National Natural Science Foundation of China(50334010)FOK YING TUNG Education Foundation(104017)
文摘The dynamic continuous cooling transformation（CCT）diagram and phase transformation rules of 510 MPa automobile beam steel,which is produced by a continuous casting of thin slab of FTSR technology in Tangshan Iron and Steel Co.Ltd.,are researched by thermal simulation experiment.The microstructure characteristics of the beam steel under different test conditions are studied by means of optical microscope and scanning electron microscope.The test results show that the critical temperatures of phase transformation Ar3 and Ar1 will all decrease with the increase of the cooling rate.When the cooling rate is lower than 20 ℃·s-1,the ferrite and pearlite phase transformations are the main parts;when the cooling rate is higher than 20 ℃·s-1,the bainite phase appears.Moreover,the microstructures of 510 MPa automobile beam steel produced by FTSR technology are also studied,and the results are basically in accordance with the CCT diagram gained from the test.
文摘590 MPa automobile beam steel strips are used mainly to manufacture the longitudinal beam of trucks.It’s welding properties are critical to the safety of truck.The microstructure and mechanical properties of welding joints processed by CO 2 arc welding with different welding parameters were studied.The results showed that the welding joints were weak when welding heat input were small and the non metal inclusions were found in the weld joints when welding heat input are big.The quality of the welding joints is good enough at 170A of the arc current and 24V of the arc voltage.Keeping the other welding parameters fixed,the incomplete fusion defect occurred in the welding joint with backward welding,but the quality of the welding joint is good with forward welding.
文摘This paper has determined the compositions and hot rolling processes of the hot rolled beam steel plates with excellent surface oxide layer for automobiles by investigating the oxide layer forming principle and its influence factors,and the feature of the steel oxide layer.The microstructure,mechanical properties,oxide layer shape and structural composition of the steel plates are analyzed by using metallographic structures examination,SEM analyzing,X-ray diffraction instrument and mechanical properties testing.The result shows that the trial hot rolled frame steel plates have an excellent oxide layer adhesion,the Fe 3 O 4 proportions is greater than 85% in the oxide layer,and the oxide layer thickness is less than or equal to 10μm.The product has been trial-manufactured more than 100 thousands ton,and used to stamp the beam parts of automobiles straightly in no pickling process.The oxide layer scarcely scales off from the steel plates,and the effect is remarkable.
