Investment Castings For Train Connecting Rods

Product Introduction

Product name: Train accessories-Investment castings for train connecting rods
Product number: TD-03-15
Casting process: water glass precision casting
Mold: general aluminum mold and steel mold
Mold material: low temperature wax
Mold shell: water glass, quartz sand
Process characteristics: The casting shape is complex, making it difficult to forge, weld and cut alloy materials, reducing machining allowance and production costs.
Casting tolerance range: CT7 TO CT9
Product weight range: 0.5KGS TO 200KGS
Blank surface finish: RA12.5
Machined surface finish: RA3.2
Casting material type: carbon steel, alloy steel, gray iron, ductile iron
 

Investment Casting
When using wax to make patterns, investment casting is also known as "lost wax casting". Investment casting usually refers to the casting scheme in which the pattern is made of fusible materials, the shell is made by coating several layers of refractory materials on the surface of the pattern, and then the pattern is melted and discharged out of the shell, so as to obtain a casting model without parting surface, and the casting scheme can be filled with sand and poured after high temperature roasting. Because the pattern is widely made of wax materials, investment casting is often referred to as "lost wax casting".
The types of alloys that can be produced by investment casting method include carbon steel, alloy steel, heat-resistant alloy, stainless steel, precision alloy, permanent magnet alloy, bearing alloy, copper alloy, aluminum alloy, titanium alloy and ductile iron.
The shape of investment castings is generally more complex, the minimum diameter of the hole that can be cast on the casting can reach 0.5mm, and the minimum wall thickness of the casting is 0.3mm. In production, some parts that were originally composed of several parts can be designed into integral parts and directly cast by investment casting by changing the structure of the parts, so as to save processing man-hours and the consumption of metal materials, and make the part structure more reasonable.
The weight of investment castings is mostly zero to tens of cattle (from a few grams to more than ten kilograms, generally not more than 25 kilograms), and it is more troublesome to produce too heavy castings by investment casting.
The investment casting process is more complex, and it is not easy to control, and the materials used and consumed are more expensive, so it is suitable for the production of small parts with complex shapes, high precision requirements, or difficult to carry out other processing, such as turbine engine blades.
 

Advantages Of Investment Casting
The dimensional accuracy of investment castings is high, generally up to CT4-6 (CT10~13 for sand casting, CT5~7 for die-casting), of course, due to the complex process of investment casting, there are many factors affecting the dimensional accuracy of castings, such as the shrinkage of the mold, the deformation of the investment mold, the linear change of the shell in the heating and cooling process, the shrinkage rate of the alloy and the deformation of the casting in the solidification process, etc., so although the dimensional accuracy of ordinary investment castings is higher, its consistency still needs to be improved (the use of medium, The dimensional consistency of castings with high-temperature wax is much improved).
When pressing the investment mold, the pressing profile with high cavity surface finish is used, so the surface finish of the investment mold is also relatively high. In addition, the shell is made by applying a refractory coating made of a special binder and refractory material that is resistant to high temperatures and applied to the investment mold, and the inner surface of the cavity in direct contact with the molten metal has a high finish. Therefore, the surface finish of investment castings is higher than that of general castings, which can generally reach Ra.1.6~3.2μm.
The biggest advantage of investment casting is that because investment castings have high dimensional accuracy and surface finish, they can reduce machining work, and only leave a little machining allowance in the parts with higher requirements, and even some castings only leave grinding and polishing allowances, which can be used without machining. It can be seen that the investment casting method can save a lot of machine tool equipment and processing man-hours, and greatly save metal raw materials.
Another advantage of the investment casting method is that it can cast complex castings of various alloys, especially superalloy castings. For example, the blades of jet engines have a streamlined outline and an inner cavity for cooling, which can hardly be formed by mechanical machining. The production by investment casting process can not only achieve mass production, ensure the consistency of the casting, but also avoid the stress concentration of residual knife lines after machining.
 

Detection Systems

Copper Silica Sol Investment Casting