铸件裂纹的成因分析及防止措施

Analyswas of Casting Crack-caused Reason and Prevention Measures

介绍了不同原因导致的铸件裂纹,提出了相应的防止措施:(1)对于6M缸盖螺栓孔和进气管结合部位产生的裂纹,进气管砂芯改为空心结构,提高砂芯的退让性,防止热裂纹缺陷;(2)对于曳引轮铸件整体开裂问题,将3个冒口颈改为1个冒口颈,不形成收缩阻碍,解决了铸件开裂问题;(3)对于缸盖进气管管口、壁厚发生变化的区域出现的裂纹,将进气管管口法兰加宽,增加铸件的强度,并将进气管管口法兰台阶去掉,消除应力集中点,防止裂纹产生;(4)对于缸盖切向气道和螺旋气道之间的裂纹,将缸盖切向气道和螺旋气道之间的圆角R3～R5 mm增大到R5～R20 mm,消除应力集中点,从而防止裂纹产生。采取上述措施后,有效地解决了铸件的裂纹问题。

The casting cracks caused by different causes were introduced,the corresponding preventive measures were proposed:(1)For the crack in joint location of the bolt hole and inlet pipe of the 6M cylinder head,the intake pipe sand core was changed into hollow structure to improve the yieldability of the sand core and prevented the hot crack defect.(2)For the integral cracking of traction wheel castings,three rwasers necks were changed into one rwaser neck,which did not form shrinkage obstacles and solved the problem of casting cracking.(3)For the cracks in the werea of intake pipe orifice where the wall thickness of the cylinder head intake pipe was changed,the flange of the intake pipe was widened,the strength of the casting was increased,and the flange steps of the intake pipe were removed,the stress concentration point was eliminated,and the crack was prevented.(4)For the crack between the tangential port and the spiral port of the cylinder head,the R3~R5 mm filleted corner between the tangential port of the cylinder head and the helical port was increased to R5~R20 mm,thereby prevented the crack occurring. The above measures could effectively solve the crack problem of castings.