Does anyone know how to prevent the separation of steel when casting steel?

Does anyone know how to prevent the separation of steel when casting steel?

Answer: (separation) cracks: 1) hot cracking:

Formed before solidification, characteristics: crack burrs, zigzag, dark color, crack shape is bent, fracture is very irregular Broken wire connection, and the surface is wider, the more narrow it is, it is the cause of hot cracking, and the mechanism is: the molten steel begins to condense after being injected into the cavity, and when the crystalline skeleton has been formed and begins to shrink the line Because the internal molten steel has not completed solidification into a solid state at this time, the shrinkage is blocked, and stress or plastic deformation will occur in the casting When they exceed this high temperature.

When the strength of the material is at its limit, the casting will crack.

2) Cold cracking: formed before solidification, characteristics: crack smooth edge, a linear, now white. The cause is stress concentration.

Crack prevention and control measures for steel castings: 1. In terms of structure, avoid excessive wall thickness differences as much as possible, resulting in inconsistent shrinkage; 2. Strictly control the pouring temperature to avoid too high pouring temperature; 3. Reinforcing ribs are set at the position where shrinkage is blocked to prevent shrinkage cracks; 4. Ensure the purity of molten steel and effectively carry out desulfurization and degassing.

Gregorian calendar: August 8, 2009 at 11:22 Lunar calendar: June 18, 2009 at noon Eight characters: Ji Chou Xin Wei Moreover, there are some restrictions on naming, for example, the name that has already been used by someone in the family cannot be used, but outsiders do not know where.

The difference is reflected in the forging process and processing form of steel.

Cast steel: The steel used to cast castings. 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 all kinds of 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.

Steel castings are made by pouring the molten iron melted at high temperature into the mold, cooling and then out of the mold, the material has more impurities, the material is brittle, the strength is poor, the internal stress is large, and the internal structure is loose.

Forging steel is a method of hot processing of steel such as forging and forging to eliminate and improve the microstructure of the material and internal defects such as casting pores and coarse columnar crystals, so that the internal structure of the material is more dense and uniform, thereby improving the strength and toughness of the material to a large extent, but the shape is limited by the processing method.

In metal smelting, ingots are divided into upper casting and lower casting.

The molten steel ingot is usually cast under the casting method, the molten steel is released from the bottom of the molten steel ladle, enters the middle cast pipe, and enters the ingot mold from below, and the residue shrinkage porosity is concentrated in the upper part of the steel ingot to ensure the quality of the steel ingot.

The ingot of non-ferrous metals is usually cast into metal ingots, such as common aluminum ingots, and impurities are attached to the upper surface and cannot be separated.

These two ingot casting methods are related to their subsequent processes. Ingot is used to roll steel, and the upper part of the ingot can be cut off to ensure quality. Aluminum ingots, on the other hand, are used in a variety of processing processes, and impurities can also be separated when melted again.

The upper casting is "pouring", and the lower casting is "casting". Obviously, the quality can be guaranteed by the lower casting than the upper casting.

The casting performance of steel is not very good, it is difficult to ensure the quality, and it is very important to ensure the temperature of molten steel.

For steel castings, if the smelting furnace can meet the requirements of the casting, the bottom casting method is adopted, and the excess riser is cut off. If the casting is large and the smelting furnace is small, multiple furnaces are needed for continuous casting, so the pouring method has to be used, so that there will be more impurities mixed in.

Is it okay to understand "poured steel" and "steel casting" in this way?

Steel is an iron-carbon alloy with a lower carbon content. Cast steel refers to the steel parts that are formed by the casting method. All-steel means that the entire component is made entirely of steel. In watches, steel - specifically refers to stainless steel, and all-steel means that the case is completely stainless steel.

Cast steel is a steel with a higher carbon content in steel, similar to the difference between cast iron and ordinary wrought iron, it has castability, high wear resistance, and high brittleness, while pure steel is repeatedly refined in oxygen, and the carbon content is lower than that of cast steel, generally between, the lower the carbon content, the purer the steel.

Cast steel: Casting steel or parts with shape requirements is processed by the casting process, which is to cast molten steel into a specific model. Cooled and formed. Cast steel, without table material, its carbon content varies on request.

Cast steel is processed according to the needs of the process, while pure steel is freshly refined.

One natural and one processed.

It's a little bit unclear, steel is: an alloy of iron, carbon, etc.; It's all already alloys, what else is pure?

One is cast and the other is pure ...

It's the amount of charcoal! ~

High school chemistry is available.

bjlaohui's is already very comprehensive.

Close the tank valve, open the door and bury the window for ventilation, cut off all power supply, avoid using open flames, wear hard-soled shoes to make rocks, walk lightly, and then of course go out to play ** (don't bend in the environment with leakage**) to find relevant personnel to deal with.

Cutting off the power supply is irrational behavior, at this time you should keep the status quo still, and any behavior that can cause static electricity and electric sparks should be prohibited.

1. Close the valve first;

2. Gently open doors and windows for ventilation;

3. During this period, Shanli prohibits all behaviors that can cause static electricity and electric sparks;

4. Go outdoors and call ** to the gas company.

5. If the distribution cabinet is outdoors, cut off the power supply immediately.

1. The definitions are different.

Steel castings refer to parts made of cast steel, which have similar properties to cast iron but have better strength than cast iron.

The "forging" of forged steel refers to the manufacturing process of changing the shape of the material without melting. Hot rolling and cold rolling are two of the most common forging methods.

2. The defects are different.

Although the defects generated in the casting process of steel castings are similar to the defects caused by the pouring of steel ingots, they are still process defects, and the common process defects include porosity, inclusions, shrinkage holes, porosity and cracks.

The common defects of forged steel parts mainly include: forging cracks, forging folding, and forging overburning. Hairlines, white spots, inclusions, delaminations, etc. will be found on the processed surface.

3. The production process is different.

Molding sand for the production of steel castings should have high refractoriness and sand resistance, as well as high strength, air permeability and concession. The raw sand is usually made of silica sand with large particles and uniform particles; In order to prevent sand sticking, the surface of the cavity is coated with paint with higher refractoriness; In the production of large parts, it is mostly used in sand molds or water glass sand faster than casting molds. In order to improve the strength and concession of the mold, various additives are often added to the molding sand.

Forged steel parts are divided into hot-rolled steel and cold-rolled steel.

Hot-rolled steel: Hot-rolled steel is to force the hot billet steel through the roll or mold to deform the billet steel and make it into I-beams, angle steel, flat bars, square steel, round bars, pipes, plates, etc. Due to oxidation at high temperatures, the surface shape of hot-rolled steel is rougher.

Cold-rolled steel: The raw material of cold-rolled steel is billet steel or hot-rolled steel coil. The final shape and size of cold-rolled steel is obtained by rolling hardened steel rolls or drawing dies at room temperature. Rolls or molds can refine the surface and the material cold work can increase the strength of the part and reduce its ductility.

1. Different processing methods.

The difference between forged steel and cast steel is mainly reflected in the processing technology (forging and casting) of steel. Forging is a plastic deformation process, whereas casting is liquid molding.

2. The performance is different.

Forged steel refers to all kinds of forgings and forgings produced by forging methods. The plasticity, toughness and other mechanical properties of forged steel parts are higher than those of steel castings, and can withstand greater impact force, so some important machine parts are made of forged steel.

Cast steel refers to a kind of steel casting produced by casting method, which is a kind of casting alloy. Cast steel can be divided into three categories: cast carbon steel, cast low alloy steel, and cast special steel.

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.

3. The role is different.

Forged steel can be applied to make brake discs for high-speed trains. It has verified the excellent performance of high-purity forged steel materials by strictly controlling the composition of harmful substances, optimizing the preparation of forging and heat treatment processes, and verifying the excellent properties of high-purity forged steel materials by mechanical properties, impact toughness and fatigue performance tests and metallographic observation, which meets the requirements of high-speed train brake discs.

Steel castings are needed in almost all industrial sectors, and are particularly widely used in ships and vehicles, construction machinery, construction machinery, power station equipment, mining machinery and metallurgical equipment, aviation and aerospace equipment, oil wells and chemical equipment. As for the application of steel castings in various industrial sectors, the situation may vary greatly due to the specific conditions of different countries.

Forged steel parts have high strength. Forging steel parts are cold forging, cold heading, forging, forging and other cold working methods, so that the internal structure of the material is more dense, improve the structure of the material crystal, eliminate the gap, so as to improve the strength and toughness of the material to a large extent.

The steel casting is melted into molten iron by steel at high temperature, poured into the mold made in advance, and cooled out of the mold, the material has more impurities, the material is brittle, the strength is poor, the internal stress is large, and the internal structure is loose. Therefore, it is best to choose forged steel parts. Forged steel parts are generally small in size and easy to process and forge, while for larger parts with low strength requirements, they cannot be forged, and are generally processed by casting, and the cost is low.

Steel: It is divided into cast steel, forged steel, section steel and other forms.

Steel is an iron-carbon alloy with a carbon content in between.

Steel casting is a general term for iron-based alloys used in the production of castings that do not undergo eutectic transformation during the solidification process.