Question 5 about forged, and stainless steel valves

Here are some of the well-known brands recognized in the valve industry, which are widely recognized and have a high reputation. While rankings may vary depending on time and market conditions, the following brands are generally considered to be among the top brands in the valve industry:

The following influential first-line brands of water system valves and industrial valves can be used as a reference, but for reference only: Suzhou Neway Valve, Shanghai Guanlong Valve, Shanghai Qizhong Valve, Sanhua, Su Yan, Shentong, Su Valve, Nanfang, Jiang.

First, the word Yao. The above manufacturers are only estimates and references, and the specific situation may vary or fluctuate at any time due to changes in a series of factors such as changes in the market, the size of the competition pattern, and the stability of product quality. As an indispensable key device in industrial production and civil facilities, the quality and reputation of the valve brand directly affect the satisfaction and trust of users.

These brands are known in the valve industry for their innovative technology, high-quality products and reliability. It is important to note that the market and industry are evolving rapidly, and different rankings may vary depending on time and region. For the most up-to-date ranking information, it is recommended to refer to industry reports, professional organizations or market research data for more detailed and accurate information.

You are confused about the concept.

It is divided into forged stainless steel, forged carbon steel, cast stainless steel, and cast carbon steel.

The choice of stainless steel or carbon steel mainly depends on the corrosiveness and working conditions of the medium.

The choice of forging and casting mainly depends on the working pressure, the pressure of the casting shell can not be too high, and the high pressure is generally forged.

**In order, forged stainless steel, cast stainless steel, forged carbon steel, cast carbon steel.

Casting, casting, forging, and forging, for those above 600, and forging, for some manufacturers, for 600.

Forged is generally represented by A102 Usually less than 50 caliber is better with forged, and the performance of forging is similar to that of casting, stainless steel is more corrosion-resistant, and others are nothing.

The stainless steel ones are definitely more expensive than the forged ones.

It depends on the application and the environment in which it is used.

Let's take a look at the space I just opened, maybe it helps! I'll speed it up!

Forging and casting are two different processing processes.

Casting: Molten liquid metal fills the cavity for cooling. It is easy to generate pores in the middle of the workpiece.

Forging: It is mainly formed by extrusion at high temperatures. Grains in the part can be refined.

Forging: Using methods such as hammering, the metal material in the malleable state becomes a workpiece with a certain shape and size, and its physical properties are changed.

Casting: The metal is heated and melted and poured into a sand mold or mold, and then cooled and solidified into a utensil.

The difference in performance.

During forging, the metal is plastically deformed, and it has the function of refining the grains, and the fibers are cut continuously, so it is often used in the manufacture of wool and rice for important parts, such as shafts, tooth theories, etc.

Casting has requirements for the processed materials, and the casting performance of cast iron and aluminum is generally better. Casting does not have many advantages of forging, but it can make parts with complex shapes, so it is often used in the manufacture of wool for weighing parts with low mechanical property requirements. For example, machine tool housings, etc.

General DN50

The following ordinary valves are forged, and DN50 and above are generally cast, if there are special requirements.

DN50 and above are also available for forging, which is suitable for particularly high conditions.

Casting valve is a valve made of casting, generally the pressure level of the cast valve is relatively low (such as PN16, PN25, PN40, but there are also high pressure, can reach 1500lb lb), and the diameter is mostly DN50

Above. Forged valves are forged, and they are generally used in high-grade pipelines, with relatively small diameters, and are generally there.

DN50 or less.

Valves are divided into cast valves and forged valves, and the two most commonly used valves are forged steel valves and cast steel valves according to the manufacturing method. Forging valves are forged valves, the nominal diameter is relatively small, and it is generally there.

Below DN50, it is generally used in high-temperature and high-pressure pipelines. Cast valves are valves made by casting, and most of the valve diameters are.

DN15 or above. The pressure level of the cast valves is relatively low, and the commonly used nominal pressure is PN16, PN25, PN40, but there are also high-pressure valves, such as PN100, PN160, PN320, etc.

Forged steel valves are mainly processed by valve forging, and cast steel valves are processed after casting and forming the valve body.

Gate valves, globe valves and check valves with diameters less than DN50 are usually forged steel valves, and ball valves are usually used at high pressure, usually 100 kg are used forged steel valves.

Porosity is easy to form in the middle of the part. Forging: Mainly high-temperature extrusion.

The particles in the product can be refined. Forging: Through hammering and other methods, the metal material in the plastic state is made into a workpiece with a certain shape and size, and its physical properties are changed.

The casting material is cast as a whole in the mold, and its stress distribution is uniform, and there is no restriction on the direction of compression. The force direction of the forging is consistent, and its internal stress is directional, and can only bear directional pressure. For castings and forgings with the same material and wall thickness, forgings are superior to castings in strength and crystal structure.

For ball valves, the wall thickness of a cast ball valve of the same pound grade and material is thicker than that of the forging. Its compressive strength is comparable to that of forgings. 2.

Cast Ball Valves can cast large diameter ball valves. Castings have high requirements for casting process, and the larger feature is that complex shapes, valve body structures and flow channels are irregular. Castings can be molded in one go.

As long as the process is passed, the large diameter valve body can be cast. 3.The compactness of the forged ball valve is good, but because the runner and shape are too complex, it cannot be formed at one time The runner is turned, and a lot of sharp transitions are formed inside, which can easily lead to uneven force and cracking at these sharp corners.

At the same time, with the modular welded design, the diameter of the forged valve seat is relatively fixed, and in some valve sizes, its diameter is too small, which affects the flow capacity. The flow resistance of the valve increases, and the efficiency of the entire system decreases. Due to the limitation of the forging process of large-diameter valves, and in order to save costs, many manufacturers usually adopt the structure of casting in the center of the valve body and forging at both ends.

It doesn't matter if it's a casting or a forging. During processing, product defects may occur. 4.

The main defects of cast ball valves are sand holes, bubbles, etc. The main defects of forgings are large grains, cold hardening, cracks, cracks, etc.

Shanghai Yuke Electromechanical answers you: the main characteristics of forged steel valves and the difference between them and other valves lies in the material, forged steel valves and cast steel valves are mainly made of steel forging process, and the processing form is different.

Cast steel: Steel from which castings are cast. A type of cast alloy.

Cast steel is divided into three categories: cast carbon steel, cast low alloy steel and cast special steel. Cast steel refers to a kind of steel casting produced by casting method. Cast steel is mainly used to manufacture some parts with complex shapes, difficult to forge or cut and form, and require high strength and plasticity.

Forged steel: Forged steel refers to various forgings and forgings produced by forging methods. The quality of forged steel parts is higher than that of steel castings, which can withstand large impact forces, and the mechanical properties of plasticity, toughness and other aspects are also higher than those of steel castings, so all important machine parts should be forged steel parts.

The main differences between cast valves and forged valves are as follows.

Castings are made of material poured in a mold as a whole, and its stress is evenly distributed and there is no restriction on the direction of compression. The forging is formed by the force in the same direction, and the stress inside it is directional, and it can only withstand directional pressure. Castings and forgings of the same material and the same wall thickness are superior to castings in terms of strength and crystalline structure.

For valves, the wall thickness of a cast valve of the same pound grade and the same material is thicker than that of a forging. Its compressive strength is equal to that of forgings. Castings for the casting process requirements are relatively high, the biggest feature is that it can make a more complex shape, the valve body structure and the flow channel are irregular, casting can be one-time molding, as long as the process is passed, you can cast a large diameter of the valve body.

The compactness of the forging is relatively good, but for the too complex runner and shape can not be formed at one time, it is often necessary to modularize, separate forging and then welding together, so the size of the forging is limited to a certain extent. Forgings often fail to produce complex, streamlined runners. The machining of the runner is made by turning, and many sharp corner transitions are formed inside, and it is easy to cause uneven stress and cracking at these sharp corners.

At the same time, the design of modular welding, the diameter of the seat of the forged valve is relatively fixed, and in some valve sizes, its diameter is small, which affects the flow capacity. It leads to the increase of valve flow resistance and the reduction of the efficiency of the whole system. Due to the limitations of the forging process of large-size valves, and in order to save costs, many manufacturers usually adopt the structure of castings in the center of the valve body and forgings at both ends.

Whether it is castings, forgings. During processing, there is a possibility of product defects. The main defects of castings are manifested in trachoma, bubbles, etc.; The main defects of forgings are manifested in large grains, cold hardening, cracks, cracks, etc.

In order to obtain qualified product quality, the corresponding castings need heat treatment to eliminate the stress in the casting process, and at the same time use X-ray, magnetic particle testing, penetrant inspection and other detection methods. For forgings, this requires strict heat treatment of the weld and corresponding testing methods to ensure it. Forgings often require ultrasound inspection.

In addition, it should be mentioned that the welding process is very strict, and the qualification of the welding engineer is also the key to ensuring the quality of the product.

The difference between forged and cast valves

Casting valve: It is to smelt the metal into a liquid that meets the requirements and pour it into the specified valve model, and after cooling and solidification, cleaning treatment, you can get a predetermined shape, size and performance of the valve casting, which is the whole process of casting valve.

After the 20th century, casting developed rapidly, creating ductile iron, malleable cast iron, ultra-low carbon stainless steel, aluminum-copper, aluminum-silicon, aluminum-magnesium alloy, titanium-based, nickel-based alloys and other cast metal materials.

The main advantage of casting is that the cost of casting production blanks is low, and it can show its economy for parts with complex shapes, especially with complex cavities. At the same time, it has a wide range of adaptability and good comprehensive mechanical properties. However, there are many materials and equipment required for casting production, and dust, harmful gases and noise will be produced to pollute the environment.

Forging valve is a processing method that uses forging machinery to apply pressure to the metal valve blank to produce plastic deformation to obtain forgings with certain mechanical properties and a certain shape and size. Forging can be divided into open forging (open forging) and closed mode forging according to the forming method. According to the deformation temperature, forging can be divided into hot forging, warm forging and cold forging.

The forging materials are mainly carbon steel and alloy steel of various compositions, followed by aluminum, magnesium, titanium, copper, etc. and their alloys. The raw state of the material is bar stock, ingot, metal powder and liquid metal. The ratio of the cross-sectional area of the metal before deformation to the die-level area after deformation is called the forging ratio.

Through forging, the loose casting state of the metal can be eliminated, and the mechanical properties of the forgings are generally better than those of the same material. Forgings are mostly used for important parts with high load and severe working conditions in machinery, except for plates, profiles or weldments that can be rolled with simple shapes. Choosing the right forging ratio has a lot to do with improving product quality and reducing costs.

Casting valve is a valve made of casting, generally the pressure level of casting valve is relatively low (such as PN16, PN25, PN40, but there are also high-pressure, can reach 1500lb lb, and most of the calibers are DN50 or more. Forged valves are forged, generally used in pipelines with high pressure levels, forged valves are mainly small calibers, generally below DN50.

"Stainless steel valve" is not necessarily a "cast steel valve", but it may also be one.

"Stainless steel" refers to the material of the valve. The body of this valve is made of stainless steel, regardless of whether it is turned, hot-forged, or cast;

"Cast steel" refers to the manufacturing process of the valve. The main body of this valve is cast from steel, regardless of whether the material is mild steel, medium carbon steel, manganese steel, or stainless steel.

If it is a valve made of stainless steel material and made by casting process, it is a stainless steel cast valve.