Roll bending process design combined with long-term basis of existing theories to practical experience, DP as a new material, it is necessary to study the roll-depth parameter.

4.1 Analysis Model Roll forming

Rounded shape is a typical roll forming process. Therefore, to separate from the simulation model to analyze, to study its characteristics, the conclusions for the general roll process instructive. In the process of selecting a rounded shape, boundary conditions imposed under the pass. Analysis of material in the first seven pass fillet molding, the forming roller flower Figure 9.

Figure 9 Roll rounded flower diagram

Q235 is a roll forming common materials, in order to roll design to provide effective reference, the DP800 and Q235 for the fillet forming roll model were compared.

4.2 Comparative Analysis of Roll Bending

Hole in the sheet in the angle and the angle after springback compared rebound values can be drawn from roll. The simulation results calculated by the two materials roll rebound value, shown in Figure 10. Comparison of DP800 with the Q235's roll Bending value, can be drawn DP800 rebound increment relative to Q235 as shown in Figure 11.

Figure 10 DP800 and Q235 Roll Bending value Figure 11 DP800 rebound increments relative to Q235

  4.3 Comparison of roll bending deformation energy

In each pass of the non-deformation zone, the total deformation energy extraction sheet data, simulation results of deformation of two materials can be compared to total deformation of DP800 with the necessary requirements for Q235 incremental percentage of the total deformation energy. Comparative results are listed in Table 2.

Table 2 DP800 deformation can be compared with mud pumpQ235

Pass number
 DP800 required total deformation energy
 Q235 total deformation energy required
 DP800 than Q235 total deformation energy of the required percentage increment
 
1
 1.55757E +03
 1.24244E +03
 25.4%
 
2
 3.65488E +03
 2.61192E +03
 39.9%
 
3
 5.29967E +03
 3.75306E +03
 41.2%
 
4
 6.99302E +03
 4.84281E +03
 44.4%
 
5
 8.81970E +03
 5.98377E +03
 47.4%
 
6
 1.02700E +04
 6.85692E +03
 49.8%
 
7
 1.18738E +04
 7.75561E +03
 53.1% cold roll forming machine
 

5 springback simulation results with the calculated results BISWAS compared rebound

In order to make simulation more effective in guiding practice, the simulation results with the roll spring design formulas commonly used BISWAS rebound results were compared.

5.1 BISWAS rebound formula [10]

, Where, =, in order to bend radius (mm), the springback radius (mm), the yield curvature (mm), E is Young's modulus (MPa), t the sheet thickness (mm), S is material yield stress (MPa).

5.2 BISWAS formula results and simulation results

And the roll by the segment arc length calculated springback angle, and simulation results are compared in Figure 12 ~ 13.

Figure 12 DP800 Roll Bending BISWAS the difference between the calculated values and simulation

Figure 13 Q235 Roll Bending BISWAS the difference between the calculated values and simulation

5.3 The amendment of the yield stress S, BISWAS formula used to calculate DP Roll Bending

Angle increases with the molding, sheet plastic strain increases, roll forming the initial yield stress also increased. Can see from Figure 12, BISWAS formula DP rebound of greater deviation, therefore, consider the bending angle increases with the yield stress (Fig. 14) into the formula DP BISWAS rebound, the results shown in Figure 15 .

Figure 14 Variable yield stress S Figure 15 DP800 Roll Bending BISWAS calculated (variable S) and the difference between simulation

6 Conclusions

A simulation model to establish roll through the simulation results in the production practice application, verify the correctness of the simulation model.

2 The Simulation Model fillet roll model and process analysis, the results showed that: compared with the Q235, with the increase of the angle molding, DP800 rebound increment and roll deformation energy increment were significantly increased. Every time forming capacity of 12 ° or so, DP800, compared with Q235, the mean rebound increment 3 °, the mean percentage of deformation energy increment of 46%.

3 will roll Bending analysis and BISWAS calculated results were compared rebound found biswas formula can not be simply applied to DP Roll Bending calculation, but should consider the yield stress increases with the bending angle characteristics, to seek new calculation.