1, casting is not allowed to have a crack, cold shut, misrun and penetrating defects.2, the casting of machining surface, the oxide inclusions is allowed, the depth shall not exceed the specified wall thickness tolerance of deviation, the area shall not exceed the casting area is 5% ~ 10%.3, casting the processing surface is allowed no more than 3 mm in diameter, depth of not more than 2.5 mm, and the depth of no more than a third of the wall thickness at that point, no more than a quarter of the wall thickness on the edge of the installation, every square metre is in quantity of not more than two single hole.Casting important non group holes machining surface are not allowed to exist, general processing surface allow depth is not greater than 1.5 mm, no more than 1.5 mm in diameter, hole for no more than three.4, allow or group of single hole hole surface defects of castings, the defects on the back of the corresponding position, do not allow the defects at the same time.5, castings to be allowed on the machining surface defects within the scope of machining allowance.6, threaded hole, thread screwing in four do not allow the defects within a pitch.