: Features :
铸件产生皮下气孔 1. Casting produces subcutaneous pores
铸件内部有集中或分散气孔 2.There are concentrated or dispersed pores in the casting
冒口下或周围出现集中或分散性气孔或缩孔且深浅不一 3. Concentrated or dispersive pores or shrinkage pores appear under and around the riser and vary in depth
铸件内或热节处产生密集蜂窝状气孔 4.Dense honeycomb pores are produced in the casting or at the hot junction
: Cause analysis :
出温度低于 1400 ℃ 浇注温度过低 1. Out temperature is lower than 1400 ℃. Pouring temperature is too low.
球化反应不充分，搅拌扒渣不够 2. Insufficient spheroidization reaction and insufficient slag stirring
渣气孔层取样分析结果 ( 质量分数 ) 如下 :C4.98% ， Mn4.67% ， P0.088% ， S0.128% ， RExOy:0.663% ， Mg0.203% 。 3. Slag gas pore layer sampling analysis results ( mass fraction ) are as follows : C4.98% , Mn4.67% , P0.088% , S0.128% , RExOy: 0.663% , Mg0.203% .
: 渣气孔主要是稀土镁的氧化物和石墨，当铁液温度低或浇注温度过低，此类夹渣不易排出 Analysis shows that the slag pores are mainly rare earth magnesium oxides and graphite. When the temperature of the molten iron is low or the pouring temperature is too low, such slag inclusions are not easy to discharge
: Prevention method :
提高出铁温度，出铁槽中铁液温度应 >1450 ℃ 1. Increase the tapping temperature. The temperature of the molten iron in the tapping tank should be > 1450 ℃.
采用半封闭式浇注系统直浇道断面：横浇道断面：溢流口：内浇道 =1.2:2:1=1.4 。 2.Semi -closed pouring system adopts direct runner section: cross runner section: overflow port: inner runner = 1.2: 2: 1 = 1.4 . > 溢流口有利于缓流。 Sprue > overflow port is good for slow flow. < 横浇道有利于撇渣。 Overflow port < horizontal runner is favorable for skimming. Inner gate overflow opening facilitates exhaust
炉前球化处理后，加人冰晶石（ NaAlF 2 ) 。 3. After the spheroidizing treatment in front of the furnace, add cryolite ( NaAlF 2 ) . MgS 化合成低溶点易凝聚的MgF 2 、 Na 2 S 、 NaO 等化合物，从溶渣中排出。 It is easy to chemically synthesize MgF 2 , Na 2 S , NaO and other compounds with low melting point and easily agglomerate with MgS , and is discharged from the molten residue. After adding cryolite, it should be allowed to stand, which is conducive to the above reaction to fully proceed
金属型需预热至 200~300 ℃ 时浇注，刷涂料要及时烤干。 4. The metal type should be poured when it is preheated to 200 ~ 300 ℃ , and the paint should be baked in time. <4%( 质量分教 ) Moisture of molding sand should be <4% when molding wet sand ( quality education )
厚大铸件浇注应采用一快、二慢、三冲。 5. For thick and large castings, one fast, two slow and three punches should be used. Small and medium pieces use one fast and two slow pouring methods