The Difference between Forged Steel Valves and Cast Steel Valves
The cast steel valve is the valve by cast. The general pressure grade of cast steel valves is relatively low (such as PN16, PN25, PN40, but there are also high pressures. They can be 1500Lb, 2500Lb). Most calibers are more than DN50. The forged steel valve is forged out, which is generally used in high grade pipeline. The caliber is relatively small, generally below DN50.
A. The casting
1. The casting
It is to melt the metal into a liquid meeting certain requirements and it is cast into the mold. After cooling and solidification and cleaning treatment, it can get a predetermined shape, size and performance of the casting (parts or blank) process.
2. The cost of casting production is low. For complex shapes, especially with complex cavity parts, it is economic. At the same time, it has wider adaptability and better comprehensive mechanical properties.
3. The casting production requires materials (such as metal, wood, fuel, molding materials, etc.) and equipment (such as metallurgical furnace, sand mixing machine, molding machine, core making machine, sand falling machine, shot blasting machine, cast iron plate, etc.). It will produce dust, harmful gas and noise and pollution to the environment.
4. The casting is one of the earliest metal hot working processes mastered by human beings, with a history of about 6000 years. In 3200 BC, copper frog castings appeared in Mesopotamia. Between the 13th and 10th century BC, China had entered the heyday of bronze casting, and the craft had reached a high level. For example, the simple square ding weighing 875 kg in the Shang Dynasty, the Yi Zun plate of Marquis Zeng in the Warring States Period, and the diopter mirror of the Western Han Dynasty were all representative products of ancient casting. The early casting was greatly influenced by pottery, and most of the castings were tools or utensils in agricultural production, religion and life, with strong artistic colors.
In 513 BC, China produced the world's first recorded cast iron - the casting tripod of the State of Jin (about 270 kg). Around the 8th century, Europe began to produce cast iron. After the industrial Revolution in the 18th century, castings entered a new period of service for large industry. Into the 20th century, the development of castings was very rapid. It has developed nodular cast iron, malleable cast iron, ultra-low carbon stainless steel and aluminum copper, aluminum silicon, aluminum magnesium alloy, titanium, nickel base alloy and other casting metal materials. It was developed a new process for gray cast iron breeding treatment. After 50's, there appeared wet sand high pressure modeling, chemical hardening sand modeling and core making, negative pressure modeling and other special casting, shot blasting cleaning and other new technologies.
B. The forging
1. It is the use of forging machinery to apply pressure on the metal billet, so that it produces plastic deformation to obtain a certain mechanical properties, a certain shape and size of forging processing methods.
2. One of the two major components of forgings. The forging can eliminate the loose state of the metal and welding holes. The mechanical properties of the forgings are generally better than the same material castings. Forgings are mostly used for the important parts with high load and severe working conditions, except for the simple plate.
3. According to the forming method, it can be divided into: ① Open forging (free forging). The use of impact force or pressure to make the metal in the upper and lower two iron (anvil block) deformation to obtain the required forgings. The two ways are mainly manual forging and mechanical. (2) Closed forging. The forging can be divided into the die forging, cold heading, rotary forging, extrusion and so on. According to the deformation temperature forging can be divided into hot forging (the processing temperature is higher than the recrystallization temperature of the billet metal), warm forging (lower than the recrystallization temperature) and cold forging (the room temperature).
4 The forging materials are mainly carbon steel and alloy steel of various components, followed by aluminum, magnesium, titanium, copper and their alloys. The original state of the material is bar, ingot, metal powder and liquid metal. Correct selection of the forging ratio has a great bearing on improving the product quality and reducing cost.
The identification of castings and forgings
1. The surface structure of the fine density of the forging
The surface of the casting should be thicker, and the machining surface of the forging should be brighter.
2. The color of the cast iron section is gray, and the color of the forged steel section is silver bright.
3. The sound
The forging is dense. The sound is clear after the blow, and the sound of the casting is dull.
4. See the difference of two sparks by the grinder grinding.
A. The casting
1. The casting
It is to melt the metal into a liquid meeting certain requirements and it is cast into the mold. After cooling and solidification and cleaning treatment, it can get a predetermined shape, size and performance of the casting (parts or blank) process.
2. The cost of casting production is low. For complex shapes, especially with complex cavity parts, it is economic. At the same time, it has wider adaptability and better comprehensive mechanical properties.
3. The casting production requires materials (such as metal, wood, fuel, molding materials, etc.) and equipment (such as metallurgical furnace, sand mixing machine, molding machine, core making machine, sand falling machine, shot blasting machine, cast iron plate, etc.). It will produce dust, harmful gas and noise and pollution to the environment.
4. The casting is one of the earliest metal hot working processes mastered by human beings, with a history of about 6000 years. In 3200 BC, copper frog castings appeared in Mesopotamia. Between the 13th and 10th century BC, China had entered the heyday of bronze casting, and the craft had reached a high level. For example, the simple square ding weighing 875 kg in the Shang Dynasty, the Yi Zun plate of Marquis Zeng in the Warring States Period, and the diopter mirror of the Western Han Dynasty were all representative products of ancient casting. The early casting was greatly influenced by pottery, and most of the castings were tools or utensils in agricultural production, religion and life, with strong artistic colors.
In 513 BC, China produced the world's first recorded cast iron - the casting tripod of the State of Jin (about 270 kg). Around the 8th century, Europe began to produce cast iron. After the industrial Revolution in the 18th century, castings entered a new period of service for large industry. Into the 20th century, the development of castings was very rapid. It has developed nodular cast iron, malleable cast iron, ultra-low carbon stainless steel and aluminum copper, aluminum silicon, aluminum magnesium alloy, titanium, nickel base alloy and other casting metal materials. It was developed a new process for gray cast iron breeding treatment. After 50's, there appeared wet sand high pressure modeling, chemical hardening sand modeling and core making, negative pressure modeling and other special casting, shot blasting cleaning and other new technologies.
B. The forging
1. It is the use of forging machinery to apply pressure on the metal billet, so that it produces plastic deformation to obtain a certain mechanical properties, a certain shape and size of forging processing methods.
2. One of the two major components of forgings. The forging can eliminate the loose state of the metal and welding holes. The mechanical properties of the forgings are generally better than the same material castings. Forgings are mostly used for the important parts with high load and severe working conditions, except for the simple plate.
3. According to the forming method, it can be divided into: ① Open forging (free forging). The use of impact force or pressure to make the metal in the upper and lower two iron (anvil block) deformation to obtain the required forgings. The two ways are mainly manual forging and mechanical. (2) Closed forging. The forging can be divided into the die forging, cold heading, rotary forging, extrusion and so on. According to the deformation temperature forging can be divided into hot forging (the processing temperature is higher than the recrystallization temperature of the billet metal), warm forging (lower than the recrystallization temperature) and cold forging (the room temperature).
4 The forging materials are mainly carbon steel and alloy steel of various components, followed by aluminum, magnesium, titanium, copper and their alloys. The original state of the material is bar, ingot, metal powder and liquid metal. Correct selection of the forging ratio has a great bearing on improving the product quality and reducing cost.
The identification of castings and forgings
1. The surface structure of the fine density of the forging
The surface of the casting should be thicker, and the machining surface of the forging should be brighter.
2. The color of the cast iron section is gray, and the color of the forged steel section is silver bright.
3. The sound
The forging is dense. The sound is clear after the blow, and the sound of the casting is dull.
4. See the difference of two sparks by the grinder grinding.
