钛合金铸件造型材料及工艺
钛合金铸件造型材料及工艺
一、钛合金铸件造型材料
一般来讲，钛合金铸件的造型材料应具有下列特性与要求：高化学惰性，高耐火度和抗热冲击性能，足够高的强度，材料均匀细致，对水分、气体吸附能力小，导热性能低，价格低廉，无毒。
二、钛合金铸件造型工艺
钛合金铸件的造型工艺有硬模铸造、石墨捣实型、熔模型和 失模型等。
(1)硬模铸造包括石墨加工型铸造和金属型铸造。石 力口工型铸模一般寿命可达3 ~ 10次，有些组合式石墨加工 寿命可达30~40次。它适用于静止浇注，也适用于离心 但只有壁厚大于10mm的钛合金铸件才适合采用石墨 工型工艺。金属型铸造工艺简单，铸件尺寸比较精确，对 _小型铸件生产成本低廉。其缺点是铸件表面常出现冷 、流痕，钛合金铸件表面存在a脆性层。
(2)石墨捣实型与普通砂型铸造的工艺方法相同，是采用高纯人造石墨粉作型砂。化工用的大部分钛合金铸件，大型钛合金铸件铸件，都是用石墨捣实型浇注出来的。
(3)熔模精密铸造，也称失蜡铸造，钛合金铸件尺寸精确， 表面光洁，可铸造形状复杂的钛合金铸件，可以提高金属材料的利用率，生产灵活性高、适应性强。
(4)消失模（EPS泡沫型）铸造工艺是将与钛合金铸件尺寸形状相似的泡沫模型黏结组合成模型簇，刷涂耐火涂料并烘干高温焙烧除去泡沫模型，然后将壳型埋在干砂中振动紧实，真空下浇注，液体金属占据模型位置，凝固冷却后形成铸件EPS消失模型壳铸造可生产蜡模不能生产的大型钛合金铸件结构件。
Titanium alloy casting molding materials and processes
First, titanium alloy casting material
In general, titanium alloy castings modeling materials should have the following characteristics and requirements: high chemical inertness, high refractoriness and thermal shock resistance, high enough strength, uniform and detailed materials, moisture, gas adsorption capacity, low thermal conductivity , Low price, non-toxic.
Second, titanium alloy casting molding process
Titanium alloy casting molding process has hardly casting. Graphite tamping type, melt model and lose model.
(1) Die Casting Including graphite casting and metal casting. Shi Li Kou type mold life of up to 3 to 10 times, some combined graphite processing life of up to 30 to 40 times. It is suitable for static casting, but also for centrifugal but only titanium alloy castings with a wall thickness greater than 10mm are suitable for use with graphite workmanship. Metal casting process is easy, more accurate casting size, low production cost _ small castings. The disadvantage is the casting surface often cold, flow marks, there is a brittle layer on the surface of titanium alloy castings.
(2) graphite tamping an
d ordinary sand casting the same process. Is the use of high purity artificial graphite powder for the band. Most of the chemical used titanium alloy castings, large titanium alloy castings, are molded with graphite tamping pouring out.
(3) investment casting, also known as lost wax casting, titanium alloy castings accurate size, smooth surface, can cast intricate shapes of titanium alloy castings, can improve the utilization of metal materials, production flexibility, adaptability.
(4) Lost Foam (EPS Foam Type) The casting process is to bond the foam model with the size and shape of the titanium alloy casting into a model cluster, brush the refractory paint and dry it to remove the foam model at a high temperature, and then bury the shell in a dry The sand vibrates tightly and is poured under vacuum. The liquid metal fills the model position. After the solidification and cooling, the EPS disappears. Shell casting can produce large-scale titanium alloy castings whose wax mold cannot be produced.