Determination of ductile iron pieces

Ductile iron pieces of inspection, including visual inspection, ultrasonic testing and magnetic test. Special inspection should pay attention to the surface pores and the surface of the difference between the trachoma, in general, the inner wall is smooth, more regular, and the surface of the trachoma is more irregular, the internal contains more dust or sand and other non-metallic household debris. If the surface of the concave defects for the pores, then, according to the test block for comparison test, if judged to be surface trachoma, because most of the root of the trachoma will also extend to the inside of the metal, generally to be polished repair. Generally on the ductile iron pieces of the magnetic test is used with fluorescent magnetic flaw detection. Since the roughness of the casting surface itself is not very high, the use of fluorescent magnetic flaw detection can reduce the impact of surface conditions on the detection sensitivity. Appearance inspection also need to pay attention to the effect of shot peening, the effect is not good when the roughness can not meet the requirements. Ductile iron surface surface retention of oxide, as well as the retention of smear and other difficult to polished large area surface defects, because such defects will affect the appearance of inspection, should be considered to re-shot or polished.