铸造补缩(冒口)系统设计
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Influence of mould filling • solidification during mould filling • heating effects of the mould during mould filling Influence of superheating • liquid shrinkage
to prevent heat cracking:为防止热裂: length of a cool block = 3 a 4 x it's thickness
冷铁的长度 = 3, 4X 其厚度
distance between cool blocks = max. it's length
冷铁间的距离 = 最大为其长度
Real Modulus differs from Geometrical Modulus by: 实际模数由下列因数影响而不同于几何形状模数 • shape of the casting 铸件形状 • alloy 合金 • mould material 模子材料 The total difference can be up to 30%.最大能达到30%
Feeding distance is the length in an infinite plate that can be feeded by the riser. 补缩距离是指冒口对一无限平板补缩的长度
• heating effect riser 4M 热效冒口4M by conduction and metal transport • endeffect 5M • effect of cooling blocks 6M
影响冒口径尺寸的参数:
-distance between the riser to the part
-冒口到铸件的距离
-shape of the neck
-冒口颈的形状
-break-cores
-冒百度文库座
冷铁
Purpose: shorten the solidification time in (a specific zone of) a part 目的：缩短铸件中有些部位的凝固时间 Cooling surface of a cooling block is equal to 2.5 times the cooling surface of sand if nog air gap is created. 冷铁的冷却表面积应是2.5倍的铸件与砂模的接触面积 thickness of cooling block = min. modulus of part at it's position(= 0.5 D) (for maximum cooling effect)
delivered volume > shrinkage volume of the part 冒口提供的补充金属体积 > 铸件凝固收缩金属的体积
• during solidification of the part the riser also solidifies • Natural riser delivers: ca. 14% of total volume (cilinder) •普通冒口提供： 圆柱形冒口 14% 体积补缩 ca. 20% of total volume (bol)
冒口的基本公式
Assumptions: 条件： 1. solidification time riser > solidification time part
冒口凝固时间 > 铸件凝固时间
2 delivered volume > shrinkage volume of the part
冒口提供的补充金属体积 > 铸件凝固收缩金属的体积
In reality this is the only option left and one should look for a directional solidification towards the risers for a complete defect-free casting
定义: 铸件模数
Nearly all casting alloys do shrink during solidification. Cast iron can compensate the shrinkage by carbon expansion.
铸铁由石墨析出膨胀来补尚金属收缩
2. The complete casting solidifies perfectly isothermally
M= Modulus plate (= 0.5 D) M= 板模数（=0.5D)
冒口颈
Mpart : Mneck : Mriser = 1 : 1.1 : 1.2 M件 : M径 : M冒口 = 1: 1.1 : 1.2 Parameters of influence on the dimensions of the riser neck:
•绝热套冒口 •发热套冒口 提供 提供
ca. 30% of total volume
30%的体积
• exothermal bus deliveres
ca. 70% of total volume
70%的体积
Feeding distance must be large enough
液态金属必须具有足够的补缩距离
补缩(冒口)系统设计
目录
1. 定向凝固 2. 定义: 铸件模数 3. 基本原理 4. 冒口的基本公式 5. 冒口颈 6. 冷铁
Theoretically no shrinkage porosities are found in the following conditions: 理论上铸件无缩孔及缩松的条件 1. The metal does not show any shrinkage behaviour and the mould wall is stable.金属无任何收缩，砂型尺寸稳定
3 feeding distance must be large enough
液态金属必须具有足够的补缩距离
solidification time riser > solidification time part
冒口凝固时间 > 铸件凝固时间
Mriser > 1.2 Mpart M冒口 > 1.2 M铸件 under the following conditions: - mould is filled at t = 0 s. (no mould filling) - temperatures riser and part are uniform at t = 0 sec. - part and risers are surrounded with the same mould material
M = V/S with M = Modulus V = Volume S = Cooling surface Examples: Sphere = D/6 (D= diameter) Cube = L/6 (L= riblength) Cylinder = Rh / (2+(R+h) (R = radius, h = height)
冷铁的厚度= 放置位置部分铸件的模数（=0.5D)
Rule of thumb to correct for the heating effect during mould filling: thickness of cooling block = part thickness (= 2Mpart)
冷铁的厚度= 铸件的厚度（=2M件)
•
The volumereduction of the castings with a constant wall thickness is found as external shrinkage in outer dimensions e.g tubes. 铸件完全绝热管状收缩。
3. The shrinkage porosities are constantly compensated by liquid metal from a riser液态收缩不断由冒口中的液态金属来补给。
(NB: M is usually given in cm!)
基本原理
Solidification time t as function of modulus:凝固时间是模数的函数 • t = A2V2/S2 sphere 球形 • t = B2V2/S2 plate 板型 with B = 1.15 A A and B depend on: • thermal properties of metal • thermal properties of sand • difference in pouring and solidification temperature Assumptions: 1. sand mould is infinity 2. contacttemperature between sand and metal is identical 3. during solidification the contact temperature is constant
• 球形冒口 20% 体积补缩
Assumptions: - metal solidifies exogeneously (in layers) - same mould material of riser and part
Thermal busses: 热套冒口 • isolation bus deliveres
to prevent heat cracking:为防止热裂: length of a cool block = 3 a 4 x it's thickness
冷铁的长度 = 3, 4X 其厚度
distance between cool blocks = max. it's length
冷铁间的距离 = 最大为其长度
Real Modulus differs from Geometrical Modulus by: 实际模数由下列因数影响而不同于几何形状模数 • shape of the casting 铸件形状 • alloy 合金 • mould material 模子材料 The total difference can be up to 30%.最大能达到30%
Feeding distance is the length in an infinite plate that can be feeded by the riser. 补缩距离是指冒口对一无限平板补缩的长度
• heating effect riser 4M 热效冒口4M by conduction and metal transport • endeffect 5M • effect of cooling blocks 6M
影响冒口径尺寸的参数:
-distance between the riser to the part
-冒口到铸件的距离
-shape of the neck
-冒口颈的形状
-break-cores
-冒百度文库座
冷铁
Purpose: shorten the solidification time in (a specific zone of) a part 目的：缩短铸件中有些部位的凝固时间 Cooling surface of a cooling block is equal to 2.5 times the cooling surface of sand if nog air gap is created. 冷铁的冷却表面积应是2.5倍的铸件与砂模的接触面积 thickness of cooling block = min. modulus of part at it's position(= 0.5 D) (for maximum cooling effect)
delivered volume > shrinkage volume of the part 冒口提供的补充金属体积 > 铸件凝固收缩金属的体积
• during solidification of the part the riser also solidifies • Natural riser delivers: ca. 14% of total volume (cilinder) •普通冒口提供： 圆柱形冒口 14% 体积补缩 ca. 20% of total volume (bol)
冒口的基本公式
Assumptions: 条件： 1. solidification time riser > solidification time part
冒口凝固时间 > 铸件凝固时间
2 delivered volume > shrinkage volume of the part
冒口提供的补充金属体积 > 铸件凝固收缩金属的体积
In reality this is the only option left and one should look for a directional solidification towards the risers for a complete defect-free casting
定义: 铸件模数
Nearly all casting alloys do shrink during solidification. Cast iron can compensate the shrinkage by carbon expansion.
铸铁由石墨析出膨胀来补尚金属收缩
2. The complete casting solidifies perfectly isothermally
M= Modulus plate (= 0.5 D) M= 板模数（=0.5D)
冒口颈
Mpart : Mneck : Mriser = 1 : 1.1 : 1.2 M件 : M径 : M冒口 = 1: 1.1 : 1.2 Parameters of influence on the dimensions of the riser neck:
•绝热套冒口 •发热套冒口 提供 提供
ca. 30% of total volume
30%的体积
• exothermal bus deliveres
ca. 70% of total volume
70%的体积
Feeding distance must be large enough
液态金属必须具有足够的补缩距离
补缩(冒口)系统设计
目录
1. 定向凝固 2. 定义: 铸件模数 3. 基本原理 4. 冒口的基本公式 5. 冒口颈 6. 冷铁
Theoretically no shrinkage porosities are found in the following conditions: 理论上铸件无缩孔及缩松的条件 1. The metal does not show any shrinkage behaviour and the mould wall is stable.金属无任何收缩，砂型尺寸稳定
3 feeding distance must be large enough
液态金属必须具有足够的补缩距离
solidification time riser > solidification time part
冒口凝固时间 > 铸件凝固时间
Mriser > 1.2 Mpart M冒口 > 1.2 M铸件 under the following conditions: - mould is filled at t = 0 s. (no mould filling) - temperatures riser and part are uniform at t = 0 sec. - part and risers are surrounded with the same mould material
M = V/S with M = Modulus V = Volume S = Cooling surface Examples: Sphere = D/6 (D= diameter) Cube = L/6 (L= riblength) Cylinder = Rh / (2+(R+h) (R = radius, h = height)
冷铁的厚度= 放置位置部分铸件的模数（=0.5D)
Rule of thumb to correct for the heating effect during mould filling: thickness of cooling block = part thickness (= 2Mpart)
冷铁的厚度= 铸件的厚度（=2M件)
•
The volumereduction of the castings with a constant wall thickness is found as external shrinkage in outer dimensions e.g tubes. 铸件完全绝热管状收缩。
3. The shrinkage porosities are constantly compensated by liquid metal from a riser液态收缩不断由冒口中的液态金属来补给。
(NB: M is usually given in cm!)
基本原理
Solidification time t as function of modulus:凝固时间是模数的函数 • t = A2V2/S2 sphere 球形 • t = B2V2/S2 plate 板型 with B = 1.15 A A and B depend on: • thermal properties of metal • thermal properties of sand • difference in pouring and solidification temperature Assumptions: 1. sand mould is infinity 2. contacttemperature between sand and metal is identical 3. during solidification the contact temperature is constant
• 球形冒口 20% 体积补缩
Assumptions: - metal solidifies exogeneously (in layers) - same mould material of riser and part
Thermal busses: 热套冒口 • isolation bus deliveres