The analysis shows that cracking of steel ML08A1 rivets with non-standard special-shaped fasteners is mainly caused rivet flanging by the high original strength and the poor plastic shape of the material. By optimizing the composition control in the range of 0. 04% ~0. 06% C

≤0. 05% Si

0.30% ~ 0.35% Mn

decreasing Ti content from 0. 021% to 0. 001% and the [N

]

in the smelting process control less than 30 x 10

-

6

the yield strength of steel decreases from 260 - 264 MPa to 219 - 226 MPa and the work hardening rate of the material can be effectively reduced

to obtain a higher plastic strain capacity and ensure the quality requirements of rivet deep processing

100 tons of rivet cracking rate from the original 8% reduces to about 0. 33%.