Five Major Differences between Forged Steel Valves and Cast Steel Valves
Should forged steel valves or cast steel valves be chosen under established operating conditions? In order to better assist you in selecting the right type, today DERVOS will introduce the five major differences between forged steel valves and cast steel valves.
1. Forging and casting valves
Casting: Fill the mold cavity with molten liquid metal for cooling. Pores are prone to form in the middle of the workpiece. Heat and melt the metal and pour it into a sand mold or mold. After cooling, it solidifies into an object.
Forging: it is mainly formed by extrusion at high temperatures. It can refine the grains in the workpiece. Using methods such as hammering to transform a metal material in a plastic state into a workpiece with a certain shape and size, and changing its physical properties.
2. Different properties of forging and casting processes
During forging, the metal undergoes plastic deformation, which has the effect of refining grain size. Therefore, it is commonly used in the rough manufacturing of important parts, such as shafts, gears, etc. There are requirements for processed materials of casting, which are generally cast iron and aluminum and have better casting performance. Casting does not have advantages as many of forging, but it can manufacture parts with complex shapes. It is commonly used in the rough manufacturing of support parts with low mechanical performance requirements. For example, machine tool casings.
3. Differences in performance between forged steel valves and cast steel valves
3.1. Pressure
Forged steel valves can withstand great impact forces due to the inherent differences in material properties, which have better plasticity, toughness, and other mechanical properties than cast steel valves. Therefore, they can be used in high pressure working environments. The commonly used pressure ratings for forged steel valves are PN100, PN106, PN320, 1500LB to 4500LB. The commonly used nominal pressures for cast steel valves are PN16, PN25, PN40, 150LB to 900LB.
3.2. Diameters
the diameter of forged valves is usually below DN50 due to the high requirements of forging technology for molds and equipment.
3.3. Leakage prevention
Casting is prone to producing sand holes during the machining process due to the process. Therefore, compared with forging technology, the anti-leakage ability of cast valves is not as good as that of forged valves. Integral forged valves have better anti-leakage ability than ordinary forged steel valves due to their valve bodies and flanges being forged by integral molds. Therefore, in some industries with high requirements for leak prevention, such as gas, natural gas, petroleum, chemical and other industries, forged steel valves have been widely used.
3.4. Appearance
Cast steel valves and forged steel valves are easily distinguishable in appearance. Generally, cast steel valves is silver, while forged steel valves is black.
4. Different application fields
The specific selection of cast steel valves and forged steel valves depends on the working environment. Generally speaking, cast steel valves are mostly used for large-diameter valves, while forged steel valves can withstand high pressure and can be used in some high-temperature factories, such as power plants and chemical plants.
5. Prices
Generally speaking, the price of forged steel valves is higher than that of cast steel valves, so it is important to choose valves according to local conditions.
1. Forging and casting valves
Casting: Fill the mold cavity with molten liquid metal for cooling. Pores are prone to form in the middle of the workpiece. Heat and melt the metal and pour it into a sand mold or mold. After cooling, it solidifies into an object.
Forging: it is mainly formed by extrusion at high temperatures. It can refine the grains in the workpiece. Using methods such as hammering to transform a metal material in a plastic state into a workpiece with a certain shape and size, and changing its physical properties.
2. Different properties of forging and casting processes
During forging, the metal undergoes plastic deformation, which has the effect of refining grain size. Therefore, it is commonly used in the rough manufacturing of important parts, such as shafts, gears, etc. There are requirements for processed materials of casting, which are generally cast iron and aluminum and have better casting performance. Casting does not have advantages as many of forging, but it can manufacture parts with complex shapes. It is commonly used in the rough manufacturing of support parts with low mechanical performance requirements. For example, machine tool casings.
3. Differences in performance between forged steel valves and cast steel valves
3.1. Pressure
Forged steel valves can withstand great impact forces due to the inherent differences in material properties, which have better plasticity, toughness, and other mechanical properties than cast steel valves. Therefore, they can be used in high pressure working environments. The commonly used pressure ratings for forged steel valves are PN100, PN106, PN320, 1500LB to 4500LB. The commonly used nominal pressures for cast steel valves are PN16, PN25, PN40, 150LB to 900LB.
3.2. Diameters
the diameter of forged valves is usually below DN50 due to the high requirements of forging technology for molds and equipment.
3.3. Leakage prevention
Casting is prone to producing sand holes during the machining process due to the process. Therefore, compared with forging technology, the anti-leakage ability of cast valves is not as good as that of forged valves. Integral forged valves have better anti-leakage ability than ordinary forged steel valves due to their valve bodies and flanges being forged by integral molds. Therefore, in some industries with high requirements for leak prevention, such as gas, natural gas, petroleum, chemical and other industries, forged steel valves have been widely used.
3.4. Appearance
Cast steel valves and forged steel valves are easily distinguishable in appearance. Generally, cast steel valves is silver, while forged steel valves is black.
4. Different application fields
The specific selection of cast steel valves and forged steel valves depends on the working environment. Generally speaking, cast steel valves are mostly used for large-diameter valves, while forged steel valves can withstand high pressure and can be used in some high-temperature factories, such as power plants and chemical plants.
5. Prices
Generally speaking, the price of forged steel valves is higher than that of cast steel valves, so it is important to choose valves according to local conditions.
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