Why is malleable cast iron unmalleable? Can malleable cast iron be forged?

Because the clumculent graphite on the cast iron metal matrix and the stress concentration caused by it is much smaller than that of gray cast iron, therefore, malleable cast iron has higher strength, especially plasticity (elongation δ up to 12%) is much higher than that of gray cast iron, and has a certain plastic deformation ability, so it is named malleable cast iron (or malleable cast iron, also known as horse iron).

The graphite in malleable cast iron is distributed in a flocculent manner, which has little fragmentation and damage to the metal matrix, and the stress concentration caused by the graphite tip is small, and the strength, plasticity and toughness of the metal matrix can play a greater role.

Therefore, the mechanical properties of malleable cast iron are higher than those of gray cast iron, especially the plasticity and toughness are much higher.

The smaller the number of flocculent graphite in malleable cast iron, the more regular the shape, the finer and more uniform the distribution, and the higher its mechanical propertiesIt doesn't matter what kind of iron it is. High carbon content and brittle .

The malleability of malleable cast iron only means that its plasticity is better than that of ordinary cast iron, and it does not mean that it can be forged, in fact, its performance is not as good as that of ductile iron.

Malleable cast iron has graphite, and when forging, the graphite will slip to form flake defects, and its performance will be greatly reduced. Therefore do not forge it. Because compared with other cast iron, he has relatively good plasticity, ductility, and his metallographic structure is flocculent, so it is called kt malleable to a certain extent.

Malleable can only be forged properly, but it is not forged because it still has graphite to cut the substrate

That's because its good plasticity and toughness are relative to ordinary cast iron, and ordinary cast iron has no plasticity, so it is called"Malleable", but still unmalleable.

In the early days, because of some complex thin-walled structures, these mechanisms should have been made of forging, but because of the complex structure, it was difficult to forge, and casting could be made of these complex structures because of the fluidity of molten iron. Therefore, people first use cast iron to cast these shapes, and then carry out various heat treatments on the cast castings to obtain different properties to meet the needs.

Through such a process, the structure that was originally forged was replaced by iron castings whose properties could also meet the requirements, so the cast iron in this case was named malleable cast iron, which means that it can be substituted for forging, rather than that the cast iron itself can be malleable.

This is just an ambiguity in the understanding of the text, and it may be very understandable itself, so I can't find the problem of people who don't understand, so I ignore the explanation, which leads to misunderstanding.

Malleable cast iron cannot be forged.

Malleable cast iron cannot be used for forging methods to make parts, this is because the form of graphite in malleable cast iron is flocculent, and the toughness is higher than that of gray cast iron, but it is not as serious as the graphite sheet segmentation matrix of gray cast iron.

Introduction to Malleable Cast Iron.

Malleable cast iron is a common kind of steel, malleable cast iron, also known as horse iron, is a kind of high-strength cast iron obtained by white cast iron through annealing and other related processes, malleable cast iron through cementite decomposition to obtain flocculent graphite.

Because the graphite in the malleable cast iron is flocculent, the fragmentation effect of the matrix of the malleable cast iron is relatively small, so the mechanical properties of the malleable cast iron are better than those of gray cast iron, and the malleable cast iron also has better toughness.

Generally speaking, the performance of malleable cast iron is a material between gray cast iron and ductile iron, and the corrosion resistance of malleable cast iron is relatively good. The malleable cast iron properties of different matrix structures are different.

For example, black-hearted malleable cast iron has better plasticity and toughness, and there is a kind of pearlite malleable cast iron that has better strength and hardness, and this pearlite malleable cast iron also has good wear resistance.

No.

Reasons why steel can be cast, but cast iron can't:

Steel has low carbon content, good toughness, and can be cast, and cast iron has high carbon content, high hardness, brittleness, cannot be forged, and can be used to make steel.

Cast iron, of course, can be forged, but what is made is not necessarily strong and has no toughness.

Malleable cast iron is not actually malleable, and the graphitization annealing time is long, and there is a tendency to replace ductile iron.

The main technology for the manufacture of malleable cast iron is to obtain the structure of white iron first and then the annealing process system. Therefore, the chemical composition of molten iron should ensure that the white iron structure is formed in the cross-section of the casting, the casting performance should be good, the mechanical properties should meet the requirements, and the malleable annealing time should be short.

The main methods to shorten the annealing time are to adjust the composition of the molten iron, carry out inoculation treatment and preheat treatment, etc

If it is normalized or quenched first, it should be kept at 300 400 for 3 5h; Accelerate the condensation rate of castings and refine grains; Trace amounts of white-mouthed elements tellurium, bismuth and graphitized nucleating agent elements boron and aluminum are added, and the mutual restraint of these elements is used to increase the number of graphitized cores and promote the graphitization process.

Cast iron ironwork: the appearance is very rough, and the sound of knocking is muffled;

Wrought Iron Wrought: The appearance is smooth, and the knock produces a crisp sound.

Cast iron is cast, which is formed by refining pig iron into a solution of iron and then casting. Wrought iron is made of solid iron forged into other shapes of iron at high temperature, cast iron is easy to break, and wrought iron is not easy to break.

Wrought iron has traces of beating on the surface, while cast iron does not. Cast iron is pig iron and wrought iron is wrought iron. The sound of striking cast iron with metal is more brittle, and the sound of striking wrought iron is louder.

For outdoor use, it also depends on your use to decide, if it is an ornament, cast iron and wrought iron are similar. Cast iron** is cheap, but wrought iron is easy to weld. If the appearance is electroplating or painting, it is almost the same.

Lump iron smelting is iron ore that is reduced with charcoal in a solid state at a lower temperature (about 1000 meters) to obtain iron with more inclusions. This kind of iron is a sponge-like solid, with more impurities, low carbon content, and soft quality, which can only be forged, not cast.

Iron tools made by heating and forging, extruding inclusions, and improving mechanical properties are called block ironmaking forgings. If in the process of repeated heating, the block iron is in contact with the charcoal fire, and the carbon penetrates and increases the carburization and hardens, it becomes the block carburizing steel.

Pig iron is an iron-carbon alloy with a carbon content of more than 2%, and the carbon content of industrial pig iron is generally in, and contains C, SI, MN, S, P and other elements, which is a product smelted by blast furnace with iron ore. According to the different forms of carbon in pig iron, it can be divided into steelmaking pig iron, cast pig iron and ductile iron.

The properties of pig iron are hard, wear-resistant, and good castability, but pig iron is brittle and cannot be forged.

The main components of cast iron and wrought iron are iron, and the main difference between the two is the difference in carbon content, cast iron generally contains carbon, and wrought iron contains carbon. Wrought iron is oxidized and removed from excessive carbon and other harmful impurities (such as sulfur, phosphorus, etc.) contained in iron by oxidizing agents (such as oxygen) at high temperatures, so that they reach the specified range of steel content.