How To Distinguish Between Cast Valves And Forged Valves

- Aug 26, 2019-





Material selection:

GS-C251.0619,WCB.WCC,LCB,LCC,LC3,4C,4D,WC6,C5,C12, C12A,CA15CF3,CF8(-196’C),CF3M,CF8M,CF8C,CD4MCu,CK3MC   uN,ZG200-400,ZG230-450,ZG270-500,2G40Cr1,ZG20CrM0.2G15C   r1Mo1V,ZG35Cr1MO.ZG16CrMOG(1Cr5Mo),ZG1Cr13,ZGOCr18Ni9 Ti.5A.KmTB   Cr26.4A




Resin sand casting, etc.

Casting valves are valves that are cast. Generally, the pressure of the cast valves is relatively low (such as PN16, PN25, PN40, but also there are high pressure valves, up to 1500Lb, 2500Lb). Most of the calibers are above DN50. Forged valves are forged, generally used on high-grade pipelines, with small calibers, generally below DN50.

First, casting

1. Casting: It is the process of smelting metal into a liquid that meets certain requirements and pouring it into a mold, and then cooling, solidifying and clearing to obtain a casting (part or blank) having a predetermined shape, size and performance. It’s the basic process of the modern machinery manufacturing industry.

2. The blank produced by casting has low cost, and it can show its economicality for parts with complicated shape, especially with complex internal cavity; at the same time, it has wide adaptability and good comprehensive mechanical properties.

3, but there are many required materials for casting production (such as metal, wood, fuel, modeling materials, etc.) and equipment (such as metallurgical furnace, sand mixer, molding machine, core machine, falling sand machine, shot blasting machine, cast iron plate, etc.) ,and it will produce dust, harmful gases and noise and pollute the environment.

4. Casting is a metal thermal processing technology mastered by humans earlier. It has a history of about 6,000 years. In 3200 BC, copper frog castings appeared in Mesopotamia. Between 13 BC and the 10th century BC, China has entered the heyday of bronze castings, and its craftsmanship has reached a fairly high level, such as the Shang dynasty;s 875 kilograms of the Si-Mu-Wu Fangding, the Warring Zeng Hou Yi Zun Pan and the Western Han Dynasty. The light-transparent mirrors are all representative products of ancient casting. The early casting was greatly influenced by pottery, and most of the castings were tools or utensils for agricultural production, religion, and life, and the artistic color was strong. In 513 BC, China cast the world;s first iron castings found in the text - Jin Kingdom Zhu Ding (about 270 kg weight). Around the 8th century AD, Europe began to produce cast iron parts. After the industrial revolution of the 18th century, castings entered a new era of service for large industries. In the 20th century, casting has developed rapidly. It has developed spheroidal graphite cast iron, malleable cast iron, ultra-low carbon stainless steel and aluminum-copper, aluminum-silicon, aluminum-magnesium alloy, titanium-based, nickel-based alloy and other cast metal materials. A new process for the inoculation of cast iron appeared. After the 1950s, there were new technologies such as wet sand high pressure molding, chemical hardening sand molding and core making, negative pressure molding, and other special casting and shot blasting.

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5. There are many kinds of castings. According to the modeling method, it is customarily divided into: 1 ordinary sand casting, including wet sand type, dry sand type and chemical hardening sand type. 2 Special casting, according to the modeling material, can be divided into special castings with natural mineral sandstone as the main modeling material (such as investment casting, clay casting, casting workshop shell casting, negative pressure casting, solid casting, ceramic casting etc.) and special castings with metal as the main casting material (such as metal casting, pressure casting, continuous casting, low pressure casting, centrifugal casting, etc.).

6. The casting process usually includes: 1 casting (making the liquid metal into a container of solid casting). The casting can be divided into sand type, metal type, ceramic type, mud type, graphite type, etc. according to the materials used. For disposable, semi-permanent and permanent types, the pros and cons of casting preparation are the main factors affecting the quality of castings; 2 melting and casting of casting metals, casting metals (casting alloys) are mainly cast iron, cast steel and cast non-ferrous alloys; 3 Casting treatment and inspection, casting treatment includes removal of foreign objects on the core and casting surface, removal of the riser, burrs and burrs, and heat treatment, shaping, anti-rust treatment and roughing machining. Imported pump valve

Second, forging

1. Forging: It is a processing method that applies pressure to a metal blank by using a forging machine to cause plastic deformation to obtain a forging having certain mechanical properties, a certain shape and size.

2. One of the two major components of forging. By forging, it can eliminate the looseness of the as-cast state of the metal, weld the hole, and the mechanical properties of the forging are generally superior to those of the same material. For important parts with high load and severe working conditions in machinery, forgings are often used except for the available rolled sheets, profiles or welded parts.

3, forging according to the forming method can be divided into: 1 open forging (free forging). The impact force or pressure is used to deform the metal between the upper and lower two irons (anvil) to obtain the required forgings, mainly hand forging and mechanical forging. 2 closed mode forging. The metal blank is subjected to compression deformation in a forging die having a certain shape to obtain a forged piece, which can be classified into die forging, cold heading, rotary forging, extrusion, and the like. Forging at deformation temperature can be further divided into hot forging (processing temperature is higher than recrystallization temperature of billet metal), warm forging (below recrystallization temperature) and cold forging (normal temperature).

4. Forging materials are mainly carbon steel and alloy steel of various compositions, followed by aluminum, magnesium, titanium, copper and the like and alloys thereof. The original state of the material is bar, ingot, metal powder and liquid metal. The ratio of the cross-sectional area of the metal before deformation to the area of the die after deformation is called the forging ratio. Proper selection of forging ratios has a lot to do with improving product quality and reducing costs.

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