NEWS
How to solve the shell crack in casting
Author:
Release time:
2021-01-19
Source:
Shell cracking is actually a normal thing in investment casting, whether it is cracking during dewaxing or during roasting or pouring. The casting manufacturer introduced that the mold shell is cracked, which can only explain one problem, that is, the strength of the mold shell is insufficient, which may be normal temperature strength or high temperature strength. Therefore, for the crack of the shell, the solution to the problem is to find out where the strength difference of the shell is.
Investment casting belongs to the model without parting surface, that is, burrs appear on the smooth surface, and the metal liquid is sincere, what the mold looks like and what it looks like. Based on this reason, the burr is actually caused by the shell crack. The reasons are: the strength of the shell is not enough to resist the stress of wax expansion during dewaxing, or the static pressure of the metal under high temperature conditions, and the ability to resist thermal shock.
In general, should be from the drying and wax is smooth, and dewaxing kettle parameters set several aspects to exclude. It should be pointed out that the factory sometimes in order to reduce costs, unlimited increase in the group tree rate, which is a very big test of the shell process and product quality. In fact, I can't see any problems in wax discharge and drying. It is a big factor that the high tree grouping rate makes it difficult to make the shell qualified in the shell making process.
Of course, the thickness of the shell is also an important consideration, it is also an integral part of the strength. If there are no cracks in the shell after dewaxing, check the condition after firing. Generally speaking, if the dewaxed shell has no cracks, the baked shell will not crack. Therefore, before casting after roasting, if the shell is cracked after dewaxing, it will only expand after roasting and will not disappear.
Of course, if these two processes are not, and then there is a crack, then there is a problem with the refractory material of the shell. If there is a problem in the dewaxing area, find the reason from the drying, shell thickness, dewaxing smoothness and parameter setting of the dewaxing kettle. If there is a problem with pouring, think of a way from the thickness and quantity of the surface layer.
Investment casting belongs to the model without parting surface, that is, burrs appear on the smooth surface, and the metal liquid is sincere, what the mold looks like and what it looks like. Based on this reason, the burr is actually caused by the shell crack. The reasons are: the strength of the shell is not enough to resist the stress of wax expansion during dewaxing, or the static pressure of the metal under high temperature conditions, and the ability to resist thermal shock.
In general, should be from the drying and wax is smooth, and dewaxing kettle parameters set several aspects to exclude. It should be pointed out that the factory sometimes in order to reduce costs, unlimited increase in the group tree rate, which is a very big test of the shell process and product quality. In fact, I can't see any problems in wax discharge and drying. It is a big factor that the high tree grouping rate makes it difficult to make the shell qualified in the shell making process.
Of course, the thickness of the shell is also an important consideration, it is also an integral part of the strength. If there are no cracks in the shell after dewaxing, check the condition after firing. Generally speaking, if the dewaxed shell has no cracks, the baked shell will not crack. Therefore, before casting after roasting, if the shell is cracked after dewaxing, it will only expand after roasting and will not disappear.
Of course, if these two processes are not, and then there is a crack, then there is a problem with the refractory material of the shell. If there is a problem in the dewaxing area, find the reason from the drying, shell thickness, dewaxing smoothness and parameter setting of the dewaxing kettle. If there is a problem with pouring, think of a way from the thickness and quantity of the surface layer.
Previous Page:
Next page:
RELATED INFORMATION
What is casting? The development of casting?
2024-05-20
New Investment Casting Process
2024-05-20
Development prospect of casting
2024-05-20
Contact Us
Address: 27 Donghai Second Avenue, Duqiao Town, Taizhou City, Zhejiang Province
Scan code to view mobile phone end