Views:3 Author:Site Editor Publish Time: 2021-12-14 Origin:Site
(1) The influence of casting structure: a. Casting wall thickness, large shrinkage rate, thin casting wall, small shrinkage rate. b. The free shrinkage rate is large, and the hindered shrinkage rate is small.
(2) The influence of casting material: a. The higher the carbon content in the material, the smaller the linear shrinkage rate, and the lower the carbon content, the greater the linear shrinkage rate. b. The casting shrinkage rate of common materials is as follows: casting shrinkage rate K=(LM-LJ)/LJ×100%, LM is the cavity size, and LJ is the casting size. K is affected by the following factors: wax mold K1, casting structure K2, alloy type K3, pouring temperature K4.
(3) The impact of shell-making materials: zircon sand, zircon powder, Shangdian sand, and Shangdian powder are used. Because of their small expansion coefficient, only 4.6×10-6/℃, they can be ignored.
(4) The effect of shell baking: Due to the small expansion coefficient of the shell, when the temperature of the shell is 1150℃, it is only 0.053%, so it can be ignored.
1. Pressure casting: Pressure casting is to press liquid or semi-liquid alloy into a metal mold quickly (filling speed can reach 5-50m/s) under high pressure (specific pressure is about 5~150MPa), and under pressure Method of solidification to obtain castings;
2. Centrifugal casting: pouring liquid alloy into a high-speed rotating mold so that it can fill the mold and crystallize under the centrifugal force. This casting method is called centrifugal casting;
3. Lost foam casting: Lost foam casting precision cast steel is also called gasification mold casting or solid casting. It is a method of making a mold with a pattern made of foamed plastic. After that, the pattern is not taken out, and the pattern vaporizes and disappears during pouring to obtain a casting.