What is cast iron? What medium?

Iron-carbon alloy with a carbon content of more than 2%. Industrial cast iron generally has a carbon content of: Carbon is mostly found in graphite form in cast iron, and sometimes in cementite form.

In addition to carbon, cast iron also contains 1% 3% silicon, as well as elements such as manganese, phosphorus, and sulfur. Alloy cast iron also contains elements such as nickel, chromium, molybdenum, aluminum, copper, boron, vanadium, etc. Carbon and silicon are the main elements that affect the microstructure and properties of cast iron.

Cast iron can be divided into:

Grey cast iron. The carbon content is high (, the carbon mainly exists in the form of flake graphite, and the fracture is gray, referred to as gray iron. The melting point is low (1145 1250), the shrinkage is small when solidified, the compressive strength and hardness are close to carbon steel, and the shock absorption is good.

Due to the presence of flake graphite, it has good wear resistance. The casting performance and cutting processing are better. It is used to manufacture machine tool beds, cylinders, boxes and other structural parts.

The grade number is followed by "HT" with two sets of numbers. For example: HT20-40 (the first number indicates the minimum tensile strength, and the second set of numbers indicates the minimum flexural strength).

White cast iron. The content of carbon and silicon is low, and the carbon mainly exists in the form of cementite, and the fracture is silvery-white. During solidification, the shrinkage is large, and it is easy to produce shrinkage holes and cracks.

It has high hardness and brittleness, and cannot withstand impact loads. It is mostly used as a blank of malleable cast iron and to make wear-resistant parts.

Malleable iron. Obtained by annealing of white cast iron, graphite is distributed in a flocculent form, referred to as tough iron. Its microstructure is uniform, wear-resistant, and has good plasticity and toughness. It is used to manufacture parts with complex shapes and strong dynamic loads.

Nodular cast iron. The gray cast iron molten iron is obtained after spheroidization, and the precipitated graphite is spherical, referred to as ductile iron. All or most of the carbon is present in the free state of spherical graphite, which is silvery-gray in fractures.

It has higher strength, better toughness and plasticity than ordinary gray cast iron. The grade is indicated by "QT" followed by two sets of numbers, e.g. QT45-5 (the first set of numbers indicates the minimum tensile strength, and the second set of numbers indicates the minimum elongation).

It is used in the manufacture of internal combustion engines, auto parts and agricultural machinery.

Compacted graphite cast iron. The gray cast iron molten iron is obtained after creeping treatment, and the precipitated graphite is worm-like. The mechanical properties are similar to those of ductile iron, and the casting properties are between gray cast iron and ductile iron. Parts and components used in the manufacture of automobiles.

Alloy iron castings. Ordinary cast iron is obtained by adding an appropriate amount of alloying elements (such as silicon, manganese, phosphorus, nickel, chromium, molybdenum, copper, aluminum, boron, vanadium, tin, etc.). Alloying elements change the matrix structure of cast iron, so that it has corresponding characteristics such as heat resistance, wear resistance, corrosion resistance, low temperature resistance or non-magnetism.

It is used in the manufacture of parts and components for mining, chemical machinery and instruments, meters, etc.

The differences between cast iron and iron are:

1. The raw material process is different.

Iron is mainly a product of iron ore smelted in a blast furnace. Cast iron is cast pig iron that is remelted in a furnace and reprocessed into casting. Therefore, the raw materials and processes of the two are different, and cast iron is the secondary processing product of pig iron.

2. Different types and categories.

Cast iron generally includes gray cast iron, white cast iron, malleable cast iron, ductile cast iron, compacted graphite cast hail iron and alloy iron castings. Iron generally includes steelmaking pig iron and cast pig iron.

3. The performance is different.

The properties of iron are hard, wear-resistant, and good castability, but pig iron is brittle and cannot be forged. Cast iron has excellent forging properties and generally has a good cutting pattern. And it has a certain wear resistance.

Commonly used cast iron grades and uses:

1. Commonly used ductile iron grades and uses.

1) The grade is QT450-10: it has high plasticity, toughness and low-temperature impact toughness.

2) The grade is QT500-7: used to manufacture oil pump gears, valve bodies, clamping bodies and parts that bear medium loads.

3) The brand of the brigade sail is QT600-3 and QT700-2: used to manufacture crankshafts, camshafts, rollers, machine tool spindles, important clamping bodies and parts.

2. Commonly used high silicon corrosion-resistant cast iron grades and applications.

1) The brand is STSI11CU2CRR: horizontal centrifugal pumps, submersible pumps, valves, cocks, tower tanks, cooling drainage pipes, negobs and other chemical equipment and parts.

2) Grades are STSI15R, STSI17R, STSI15MO3R: all kinds of centrifugal pumps, valves, plugs, pipe fittings, tower tanks, low-pressure vessels and various non-standard parts.

3) STSI15Cr4R: In the cathodic protection system of impressed current, it is widely used as an auxiliary anode casting. <>

The difference between pig iron and cast iron is: different raw material processes, different types and categories, and different properties.

1. The raw material process is different.

Pig iron is mainly a product of iron ore smelted in a blast furnace. Cast iron is cast iron is re-melted in a furnace and reprocessed into casting. Therefore, the raw materials and processes of the two are different, and cast iron is the secondary processing product of silver pig iron.

2. Different types and categories.

Cast iron generally includes gray cast iron, white cast iron, malleable cast iron, ductile iron, compacted graphite cast iron and alloy iron castings. Pig iron generally includes steelmaking pig iron and cast pig iron.

3. The performance is different.

The properties of pig iron are hard, wear-resistant, and good castability, but pig iron is brittle and cannot be forged. Cast iron has good forging properties and generally has a good cutting type. And it has a certain wear resistance.

Uses of pig iron and cast iron:

1. The use of pig iron: gray iron is used to manufacture various castings, such as casting various machine tool beds, iron pipes, etc.; Ductile iron is widely used in the manufacture of advanced castings such as crankshafts, gears, pistons, and a variety of mechanical parts.

2. The use of cast iron: malleable cast iron is used to manufacture parts with complex shapes and strong dynamic loads; Alloy iron castings are used in the manufacture of parts and components for mining, chemical machinery and instruments, meters, etc.

<> iron-carbon alloys. As the name suggests, cast iron is mainly made of iron, but it also contains carbon and silicon. The iron in the casting mold contains a carbon component, but this carbon is mainly made of graphite, and the content of this graphite is not excessive, and the amount of separating orange is maintained between 2.5 and 3 percent of the 3 yards.

Speaking of silicon, it is actually not very much, and it remains at one to three percent, because it is mainly based on iron. These carbon and silicon, as well as other more or less metallic components, are mainly present to maintain the properties of cast iron.

Cast iron is an iron-carbon alloy with a greater carbon content, which is made of high-temperature smelting and casting of steel and alloy materials such as industrial pig iron and scrap steel.

In addition to iron, carbon in other cast irons is also precipitated in the form of graphite. If the precipitated graphite is flaked, this kind of cast iron is called gray cast iron or gray cast iron, worm-like cast iron is called vermiculous graphite cast iron, flocculent cast iron is called malleable cast iron or cast iron, and spherical cast iron is called ductile cast iron.

Extend your data. Ductile iron castings have been used in almost all major industrial sectors that require high strength, high plasticity, high toughness, high wear resistance, heat and mechanical impact resistance, high and low temperature resistance, corrosion resistance, and dimensional stability. To meet these variations in conditions of use, ductile iron is available in many grades that offer a wide range of mechanical and physical properties.

In accordance with ISO1083, most ductile iron castings are mainly produced in an unalloyed state. Obviously, this range includes high-strength grades with a tensile strength greater than 800n mm2 and an elongation of 2%.

At the other extreme are high plasticity grades, which have an elongation of >17% and a correspondingly lower strength (minimum 370 nm2). Strength and elongation are not the basis for designers to select materials, other decisive and important properties include yield strength, elastic modulus, wear and fatigue strength, hardness, and impact properties.

In addition, corrosion resistance, oxidation resistance, and electromagnetic properties can be critical for designers. To meet these special applications, a group of austenitic ductile irons, commonly known as nickel-resistant ductile irons, was developed. These austenitic ductile irons are mainly alloyed with nickel, chromium, and manganese and are listed in international standards.

Pearlescent ductile iron has the characteristics of medium and high strength, medium toughness and plasticity, high comprehensive performance, good wear resistance and vibration damping, and good casting process performance. Its properties can be altered by various heat treatments. It is mainly used for crankshafts, camshafts, connecting shafts, connecting rods, gears, clutch plates, hydraulic cylinders and other parts of various power machinery.

Cast iron, which is a ferroalloy, contains carbon elements, etc.

The main material of <> cast iron is iron. The carbon content of cast iron is higher than that of the book. It belongs to the alloy product.

It is a multi-element alloy with Fe, C, and Si as the main components, and contains more impurities such as Mn, S, and P than carbon steel. If a certain amount of alloying elements is added, the mechanics or physicochemical properties of the cast iron can be changed. Alloy cast iron can also be expressed in a variety of forms, such as:

Ductile iron, heat-resistant cast iron, etc., as well as special cast iron used in military applications by other states, such as low-noise cast iron on submarines.

Cast iron is a general term for an alloy composed of iron, carbon, and silicon. Cast iron is an iron-carbon alloy with a greater carbon content than usual. It is a multi-alloy that contains more impurities such as manganese, sulfur, and phosphorus than carbon steel.

Sometimes, in order to improve the mechanical properties or physical and chemical properties of cast iron, a certain amount of alloying elements will be added during its processing process to obtain alloy cast iron. <

Cast iron is a general term for an alloy composed of iron, carbon, and silicon. Cast iron is an iron-carbon alloy with a greater carbon content than usual. It is a multi-alloy that contains more impurities such as manganese, sulfur, and phosphorus than carbon steel.

Sometimes, in order to improve the mechanical properties or physical and chemical properties of cast iron, a certain amount of alloying elements will be added during its processing process to obtain alloy cast iron.