1个孔缺陷
Hole defects include porosity, shrinkage, shrinkage, slag hole, sand hole, iron bean.
Preventive measures:
Porosity: the charge should be cleaned, the ferroalloy should be baked well, the ladle should be baked well during pouring; the overheating temperature and time of molten metal should be controlled by reasonable melting process, the cooling rate of castings should be accelerated, or solidified under pressure, and the gas should be precipitated; the appropriate pouring process, gating system and pouring conditions should be selected to facilitate the discharge of gas; the air permeability of the mold shell should be improved, and the exhaust hole should be added when necessary; the suitable temperature of molten metal, pouring temperature and baking temperature of the mold shell should be added; the roasting mold shell should be fully roasted; the particle size of binder and refractory should be reasonably selected.
faci收缩:正确设计的浇注系统litate casting and sequential solidification and shrinkage; improvement of casting structure to make wall thickness as uniform as possible or increase process subsidy and cold iron; use of appropriate pouring process, such as high temperature, low temperature pouring; increase mold cooling rate, or reasonable mold formation, increase wax mold spacing and improve local heat dissipation conditions; reduce molten metal temperature during pouring and increase the height of pressure head; select smelting alloy with low shrinkage if necessary.
收缩:调整合金组成,减少合金固化范围,在熔化和倒入过程中充分脱氧和脱气,以减少气体对凝固收缩的影响;改善铸造结构,合理地设置浇注系统,增加压力头的高度并增加收缩能力;选择合适的浇注过程,严格控制熔融金属的浇注温度;选择良好的热导率壳材料,改善铸件的冷却条件,并加快铸件的冷却速度;改善内门的位置,这对顺序固化有益。
Sand hole: keep wax and gate rod clean, prevent mold shell from falling into cavity during dewaxing, handling, storage, roasting, pouring or sand filling. Before pouring, vacuum cleaner should be used to clean the mold cavity; select suitable shell material, reasonable shell making process, strictly operate, avoid shell layer stratification; improve gating system design, avoid direct entry of refractory material into cavity and slow down the impact of molten metal on cavity surface; pay attention to pouring operation, slow down and fast before pouring, avoid severe scour of molten metal to cavity
Slag hole: strengthen charge management, adopt clean charge when smelting; use proper amount of slagging agent and deoxidizer when smelting, molten metal should have enough static time, which is beneficial to slag floating; remove slag on ladle before pouring; improve gating system design; Improve the height of ladle nozzle to shell gate cup.
铁豆:当第一两层涂层,工资attention to the operation, to eliminate the sharp angle, corner bubble; the new coating should be static for a certain time, when adding wetting agent, should add appropriate amount of defoamer; wax mold should be degreased before coating; improve casting design, sharp angle, corner should be smooth transition.
2个精神分裂缺陷
Cracks include: hot crack, cold crack.
Preventive measures:
Hot crack: improve casting structure, wall thickness as uniform as possible, increase casting round corner or add process bar; improve shell material or reduce shell layer number, add appropriate amount of additive, increase pouring temperature, increase shell concession; improve pouring system design; select reasonable pouring process; select materials with low thermal cracking tendency, keep furnace clean, select reasonable smelting process, add rare earth elements in appropriate amount, improve high temperature strength and plasticity of castings.
冷裂缝:改善铸造结构,例如均匀的壁厚,消除尖角,增加工艺加固,控制冷却速率以适应合金收缩;采用较少的磷炉,采用合理的熔化过程,减少杂质含量,改善熔融金属质量;清洁铸件或拆卸门时,冲击力不应太大。
3表面缺陷casting products
Surface defects include sand sticking, scarring, sand clamping and cold insulation.
Preventive measures:
Sanding: reasonable selection of shell materials and ensure their quality, full deoxidation, minimization of molten metal oxidation, and removal of oxide produced; control of humidity and storage time of shell storage site, use of reasonable roasting process; proper reduction of molten metal temperature and shell temperature during pouring; improvement of casting structure and heat dissipation parts; proper improvement of surface coating viscosity; proper reduction of molten metal temperature during pouring; proper reduction of pouring temperature of molded shell; proper reduction of height of pressure head.
Scarring: the coating should be fully stirred, after hanging, the air is dry well and hardened fully; reduce the density of binder in the surface coating; reduce the temperature of molten metal and shell when pouring properly, Reduce oxide in molten metal and low melting point inclusions in shell surface; improve casting structure.
Sand clamping: prevent mold shell delamination, select reasonable pouring process, reduce stress, avoid inner surface rupture of mold shell, improve casting structure, avoid large plane or concave as far as possible, design inner gate correctly, avoid local overheating; Select reasonable shell making process and strictly implement, fully harden or dry well, make coating close combination, improve shell strength.
Cold insulation: properly increase the temperature of molten metal and shell during pouring, improve the design of gating system, increase the number and position of cross section and inner gate of gating system, so as to shorten the filling time of molten metal in cavity; properly increase pouring speed, make molten metal enter cavity continuously and smoothly, and avoid the phenomenon of breaking flow; when pouring, put cover agent in the ladle in advance to prevent secondary oxidation of molten metal; make molten metal filling smoothly during pouring.
4 Defects in size, shape and weight
Dimensional shape and weight of unqualified defects include: flying wings, inadequate pouring, deformation, dislocation, Residues in the cavity, Pit, Inclusions.
Preventive measures:
飞翼:制作模具时严格控制蜡材料的温度和蜡压;制作模具之前,请仔细检查分隔表面并清理;改进按压类型的设计,并合理地选择材料;控制压迫类型的制造质量,确保分隔表面的准确性和粗糙度;指定合理的服务寿命。
Insufficient pouring: strictly control the temperature of wax material after stirring; strictly control the injection pressure, and contact wax injection can not be interrupted; improve the pressure design to facilitate exhaust.
Deformation: reasonable selection of binders and refractories as well as paint, shell making and pouring process; control of coating ratio, viscosity and temperature, pay attention to shell coating and hanging operation; shell to prevent a certain time to dewaxing; choose a reasonable roasting process, strictly control roasting temperature and time; strengthen the regular detection and daily maintenance of roaster; shell roasting, immediately after pouring.
Dislocation: lock the live block when pressing, counteract the pressure of wax filling; determine the reasonable service life of the pressing type; select the injection pressure reasonably according to the size, shape and wax material of the wax mold.
腔残留物:后壳是hardened, it should be fully dried; select a reasonable roasting process and strictly control the roasting temperature and holding time: regularly check the roasting furnace to meet the process requirements; thoroughly clean the sprue cup before dewaxing Excess shell material on the top to avoid the shell material falling into the cavity during the dewaxing process; select a reasonable dewaxing process to strictly control the temperature and time of dewaxing; when replacing the dewaxing solution, completely remove the dewaxing The shell material at the bottom of the tank; the shell storage place should be managed in accordance with the 5s requirements, the shell should be stored upside down to prevent the shell material from falling into the cavity; be careful to avoid sprinkling the molding sand into the cavity without pouring.
Pit: Choose dry and clean charge, choose reasonable smelting process, and adopt secondary deoxidation; choose surface layer shell material reasonably; choose reasonable shell roasting process, strictly control roasting temperature and time, and eliminate residue in the cavity Make the shell white after firing; select a reasonable binder according to the material of the casting, such as silica sol binder; appropriately reduce the temperature of the molten metal and the shell during casting to speed up the cooling rate.
夹杂物:使用前选择干净的充电,喷砂或射击。在使用合金之前,应对其进行检查并正确烘烤,并在必要时使用脱硫处理;选择合理的熔化过程和倒入过程,并在必要时使用高温使用过滤器屏幕或惰性气体;在冶炼过程中严格脱氧以保护熔融金属的表面。在释放熔融金属之前,让它静置2分钟以漂浮并去除它们。将其放入钢包的第一覆盖剂中,以防止倒入熔融金属时二级氧化;适当地升高熔融金属和霉菌壳的温度,这有利于夹杂物的漂浮。
These kinds of the defect are common for steel casting manufacturers. A responsible steel casting company should demonstrate those defects and provide prevent solution for their customers. As the leader steel casting company in China, we have profesional steel investment casting factory, and are experienced to deal with these defects and provide perfect casting products to our customers. Our steel casting foundry is the capacity to satisfy your requirement.