How to solve the problem of a small amount of carbide on the surface of the workpiece during carburi

The blank is normalized, then machined, and finally heat treated.

There are two kinds of carbides, bulk carbides and reticulated carbides, which often form massive carbides when the carbon potential is out of control in the strong permeability and diffusion stage, and in the cooling process, reticulated carbides are often formed when the carbon potential is out of control or the cooling rate is slow, and if the carbon potential is too high during the quenching process, reticulated carbides are sometimes formed. According to GB T25744-2010, carbide 1 grade 3 is qualified, and the surface hardness is 58HRC is qualified.

Reply 5 I feel that the amount of carbide is also related to the amount of furnace, the flow rate of methanol, and the cycle of carbon burning, if it is processed in a multi-purpose furnace, there is a small amount of carbide exists, it is also a dangerous signal, if you are not careful, it will be out of tolerance (there are fewer carbides in the multi-purpose furnace, most of them exist in the form of residual r) personal humble opinion, please correct the wrong place.

A small amount of carbide is good for wear resistance, if you don't want to have it, you can reduce the carbon potential of diffusion, increase the diffusion time, and increase the quenching temperature.

Reply 6 Your analysis is reasonable, in order to increase the carburizing speed, it is also necessary to increase the carbon potential appropriately, as long as there is no problem with the probe and equipment to be detected, the surface carbide level can still be achieved after the optimization of the carburizing process, within the technical requirements.

Reply 4 Carbides within level 3 are ideal tissues... But it is also necessary to analyze whether there is an abnormality in the detection instrument? Normal words do not need to be adjusted.

Hello dear <> my answer is as follows, please be patient and take a look at the <>

Carburizing quenching is a process in which carbon atoms are infiltrated into the surface layer of steel to improve the surface hardness and wear resistance of the workpiece. During the carburizing process, some carbides may form on the surface of the workpiece, which may affect the degree of dryness and cleansing of the surface of the workpiece. In order to deal with the surface of the first branch of the clean carburizing and quenching workpiece, the following methods can be used:

1.Machining: The surface of the workpiece is machined with mechanical tools to remove carbides and other impurities from the surface.

This method is suitable for dismantling in cases where carbide is more severe. 2.Chemical Treatment:

The surface of the workpiece is cleaned with chemical solvents to remove carbides and other impurities from the surface. Commonly used chemical solvents include hydrofluoric acid, nitric acid, etc. 3.

Electrolytic treatment: Electrolytic treatment is carried out on the surface of the workpiece with electrolyte to remove carbides and other impurities on the surface. This method is suitable for working with more complex surface shapes.

4.Laser treatment: A laser is used to treat the surface of the workpiece to remove carbides and other impurities from the surface.

This method is suitable for working with finer surface shapes. When treating the surface of carburizing and quenching workpiece, the appropriate treatment method should be selected according to the specific situation of the workpiece surface to ensure the treatment effect and the quality of the workpiece surface.

There may be a residual layer of carbide, oxide or other contaminants on the surface of the workpiece after carburizing and quenching. To get it clean, you can try the following:1

Mechanical cleaning: Mechanical cleaning with metal brushes, sandpaper, or abrasives can remove some surface contaminants. Pay attention to the use of appropriate force and speed to avoid damaging the surface of the workpiece.

2.Chemical Cleaning Instructions: Contaminants can be dissolved and removed from surfaces using appropriate chemical solvents or cleaning agents, such as pickling, caustic or solvent clear rubber detergents.

When using cleaning chemicals, safe operating procedures should be followed and attention should be paid to the impact on the material and surface quality of the workpiece. 3.Heat Treatment:

In some cases, by heating the workpiece again to a high temperature, residual carbides and oxides can be converted into a form that can be easily removed. This method needs to be carried out under specific temperature and time conditions, which can be done in consultation with a heat treatment expert. 4.

Electrochemical cleaning: Using electrochemical methods such as electrolytic cleaning or electrolytic decarburization, contaminants can be removed from the surface of the workpiece. This requires the use of electrochemical equipment and an appropriate electrolyte, as well as the following of specific operating procedures.

Quenching can reflect the effect of carburizing, obtain high hardness, and achieve wear resistance and load resistance. Tempering is to ensure that the quenched product will not be too hard and brittle, and to ensure the service life.

Carburizing is generally done to improve the wear resistance of the surface, and as the carbon concentration increases, the wear resistance is also good. After carburizing, the normalized structure of high-carbon steel obtained without quenching is obtained, and the reticulated carbide pearlite structure is obtained under the condition that the carbon concentration is sufficient and the cooling rate is slow enough, which cannot play a wear-resistant role.

The purpose of quenching is to improve the hardness, the quenching and tempering treatment itself is quenching and high-temperature tempering, quenching is to get as much martensite structure as possible to get high hardness, and tempering is to decompose martensite for the second time to form sophtenite, so as to obtain good mechanical properties.

The strength of Q195 itself is too low, and the carburizing layer is only as deep as 45 after three hours, and the highest is 55HRC after steel quenching and tempering treatment, and the strength cannot go up after quenching, and your carburizing treatment is only three hours.

The hardness of the carburized parts has been greatly improved, but the brittle material is prone to fatigue cracks, and quenching and tempering can increase the toughness of the parts.

Answer]: The surface of the workpiece is high carbon after wrong carburizing, and only by quenching and tempering can the potential of high carbon be realized, and high hardness and wear resistance can be obtained.

Carburizing can make the surface of the carburized workpiece obtain a high hardness and improve its wear resistance.

The purpose of quenching is to make the supercooled austenite carry out martensite or bainite transformation to obtain martensite or bainite structure, and then cooperate with tempering at different temperatures to greatly improve the rigidity, hardness, wear resistance, fatigue strength and toughness of steel, so as to meet the different requirements of various mechanical parts and tools. It can also meet the special physical and chemical properties of some special steels such as ferromagnetism and corrosion resistance through quenching.

The purpose of carburizing is to increase the carbon concentration on the surface of the workpiece, so as to achieve the purpose of improving the surface hardness and wear resistance after quenching.

Tempering is generally used to reduce or eliminate internal stresses in hardened steel, or to reduce its hardness and strength to improve its ductility or toughness. The quenched workpiece should be tempered in time, and the required mechanical properties can be obtained through the combination of quenching and tempering.

Heat treatment process is a part of metal technology, which is a broad and easy science, if you want to understand the heat treatment process in depth, it is recommended to study metal technology systematically.

Carburizing is a chemical heat treatment process performed on mild steels (carbon or alloy steels).

Some workpieces, such as machine shafts, gears, etc., require part of the working surface (bearing position, spline position or gear tooth surface) to have high hardness and high wear resistance, and at the same time, the core is required to have high impact resistance to withstand impact loads.

The use of low carbon steel plus carburizing and quenching treatment can better achieve this purpose: the impact resistance of the core of low carbon steel is higher, and the hardness and wear resistance are improved after quenching treatment after carburizing on the surface.

After carburizing, quenching and low temperature tempering is a heat treatment method to achieve high hardness of the surface layer, after quenching low temperature tempering, the surface layer obtains tempered martensitic structure, the hardness can be in HRC55-60, and the wear resistance reaches a high level.

There are two options:

Direct quenching method Direct quenching refers to the direct quenching of parts after carburizing, cooling or furnace with the furnace and cooling to a temperature higher than AR1 or AR3 (generally 780 850), and then tempering at 150 200 for 2 3h after quenching.

The purpose of cooling or pre-cooling with the furnace is to reduce the shape and cracking of quenching. At the same time, it can also precipitate some carbides from high-carbon austenite and improve the surface hardness. The direct quenching method after pre-field carburizing is simple to operate, low cost and high efficiency, and can also reduce quenching change and surface oxidative decarburization.

The disadvantage is that the structure is coarser and the performance is poor after heat treatment. The direct quenching method is suitable for parts made of intrinsically fine-grained steel, such as 20CrMnTi, 20CrMn, 20MnB, etc.

One-time quenching method After the parts are carburized, they are cooled with the furnace or the furnace pit to room temperature, and then reheated to the quenching temperature for quenching slow fire and low temperature tempering, which is called the one-time quenching method.

The heating temperature after a quenching depends on the steel grade and the properties of the ball. After the quenching of alloy steel carburizing, the AC3 temperature (850 900) is slightly higher than that of the heart tissue, so that the heart tissue is refined, and the low-carbon martensitic structure of the heart is obtained to ensure high heart strength. For carbon steel, choose between A C1 and Ac3 (about 820 850).

For some workpieces whose core strength requirements are not too high and only require good surface wear resistance, such as gauges and templates, it is advisable to choose a temperature slightly higher than AC1 (770 820).

For some parts that require high surface hardness, good wear resistance, internal toughness and impact resistance, this slippery surface carburizing and quenching method can be solved. For example, some shaft parts and some gear parts need to have high surface hardness and good internal toughness. This prevents the occurrence of fractures and tooth chipping accidents when subjected to shock loads.