How to distinguish between forged flanges and cast flanges?

The flanges that are commonly used are basically forged. The most straightforward way to distinguish them is that forged flanges can be welded using ordinary welding materials, while cast flanges require welding materials specific to castings

The most straightforward approach is to require a material certificate when storing the items. It’s not easy to analyze this based on appearance; here are some personal insights: First, there is a difference in price – the flanges available on the market that are cast are the cheapest, those that are cast and forged come next, while those that are purely forged are more expensive. This means that you need to compare prices at various stores before you can arrive at an approximate conclusion. Second, conduct a destructive analysis: cut the flange in half; cast flanges have sand inclusions, while fully forged flanges do not. Cracks can sometimes be found in cast and forged flanges. Third, it is distinguished by the size and finish of the flange (this is not something that laypeople can usually tell apart). ): The typical dimensional negative tolerance for cast flanges in the market is 1–5 mm; the edge chamfers are irregular, and the burrs on the edge holes are not smooth. Because it’s cheap, the quality of workmanship isn’t as good. Forged flanges have tight tolerances or positive tolerances. Difference between cast steel flanges and cast iron flanges: Cast iron flanges have poor toughness and can generally be broken by hitting them with a hammer. The material of the flange is usually low-carbon, right? Otherwise, welding it would result in easy cracking. Addition 1: Weight. Flanges made by casting and those made by forging have different weights. Addition 2: It’s easy to distinguish between low-pressure cast parts and forged parts; they can be identified just by their texture and appearance. For example, the flanges of low-pressure plumbing valves are usually cast parts with lower prices, while the flanges of high-pressure valves used in hydraulic systems are forged blanks that are then machined into shape. There is also a type of part known as a precision-cast part, which differs from ordinary cast parts in that it has a higher density; it is usually formed in one step without the need to remove much material through machining. This manufacturing method is generally more complex and results in higher costs. The advantage is that it allows for the creation of complex structures while still ensuring strength. Hydraulic valve bodies are typically manufactured using this method, though it is expensive. Additionally, cast parts can be divided into cast iron and cast steel, with cast steel being superior to cast iron due to differences in the materials used.

The main difference lies in appearance: the surface of castings is relatively rough, while the surface of forgings is finer.