CNC Knowledge: Positive fire, receipt, extinction and recovery!

The difference between the receipt and the fire:

The difference between the receipt and recovery is: (in other words, the receipt is not the hardness and the fire always retains a certain hardness).

Ignition:

The organization of a high temperature recovery is the fire to recover the body of SU. The ignition is generally not used alone. temperature. Receive the Auscoons, Qurennes and Sori respectively.

The combination of high temperature recovery after extinction is called mechanical properties combined with better, hardness and plasticity and tenacity. Therefore, it is widely used in important structural parts such as cars, tractors, machine tools, etc., such as connectors, bolts, gears and trees. Hardness is usually HB200-330 after ignition.

RECOIVE:

During the receipt process, the transformation of pearls. Devasive receipt is a receipt process caused by the treatment of plastic deformation, welding, etc. and residual stress in the flow. Forgeing, casting, welding and cut are internal constraints inside the room.

The internal stress generated when processing exfoliation and elimination of the process elimination process is very important. The heating temperature of the exfoliating receipt is lower than the temperature of the phase change, so no organizational transformation has occurred during the entire heat treatment process. Internal stress is mainly eliminated by the room during the preservation of heat and the cold cold process.

In order to eliminate the internal stress in the room, the heating temperature must be checked during heating. Generally, it is low in the oven, then heated to around 100 ° C / h to heat at the specified temperature. The heating temperature of the welding part must be slightly greater than 600 ° C. The insulation time depends on the situation, generally from 2 to 4 hours. The upper limit of the insulation time of the casting stress, the cooling speed is controlled at (20-50) ° C / h, and the cold can be released from the cold at less than 300 ° C.

Treatment of time can be divided into natural news and artificial news. The receipt, it saves time than natural speed, and the elimination of residual constraints is deepened.

What is fire?

The ignition is to heat the metal or the parts at a certain temperature. Timper and recovery combination as final heat treatment. The main objective of caliber and recovery is:

1) Reduce internal stress and reduction in fragility.

2) Adjust the mechanical performance of the part. and tenacity.

3) Size of the stable part. By triggering, the Gold Phase organization can stabilize to ensure that it will no longer deform during the future use process.

4) Improve the cutting performance of certain alloy steel.

In production, it is often based on the requirements of parts. Depending on the different heating temperature, the ignition was divided into low -temperature recovery, the average temperature recovered and the high temperature is restored. The combination of extinction and subsequent recovery at high temperature is called quality adjustment, that is to say, while having a strong resistance, it has good plastic tenacity. It is mainly used to manage the structural parts of the machine with larger loads, such as the main axis of the tool-machine, the half-axis of the car bridge and powerful equipment.

What is caliber?

The caliber is to heat the metal material or the parts at the temperature of the phase change. The caliber consists in obtaining the fabric of Martensite, and after recovery, the part can obtain good use of performance to give a complete game to the potential of the materials. The main goal is:

1) Improve the mechanical properties of metal materials or parts. For example: improving hardness and abrasion resistance of tools, rolling, etc., improve the elastic limit of the spring and improve the complete mechanical properties of the parts of the tree.

2) Improve the performance of materials or the chemical performance of certain special steel. Like improving the corrosion resistance of stainless steel, increasing the permanent magneticity of magnetic steel.

When cooling and cooling, in addition to the need to be reasonably selected for the extinction environment, there must be correct soil methods. .

The differences and connections of positive fire, extinction, receipt and recovery

Goal and purpose of positive fire

① Steel Analysis for the Asian Communist Party, positive fire is used to eliminate overheated raw crystalline tissue and flowing fabrics, forging and welded parts of Wei.

② For the analysis of co-analysis steel, positive fire can eliminate the carburee body two-stroke from the mesh and refine the light body of pearls, which not only improves mechanical properties, but also helps the future receipt ballization.

③ For thin steel plates with low carbon content, positive fire can eliminate the free carburetor body from the world of crystals to improve its deep shortening performance.

④ For low carbon steel and low-alloy steel with low carbon content, positive fires can be used to get more light beady tissue to increase hardness to HB140-190, avoid the phenomenon From “sticky knife” during the cut, improves the petrol cutting process for medium-carbon steel, it is more economical and practical to use the fire to use the fire and the receipt.

⑤ For ordinary carbon average structured steels, during low mechanical performance, it is possible to replace the queen and recovery at high temperature with a positive fire, which is not only easy to use, but also stabilizes the fabric and the size of the steel.

⑥ A positive fire at high temperature (150 to 200 ° C above AC3) can reduce the analysis of the composition of the flow and forgeing due to a high high temperature diffusion speed. After a positive fire at high temperature, rough grains can be refined by the second positive fire at low temperature.

⑦ For some low and medium carbon alloy steels used for turbines and steam boilers, positive fires are often used to obtain Bellian fabric, then bought at high temperatures.

In addition to steel and steel parts, positive fire is also widely used for the heat treatment of the ball and the cast iron ink, so that it can obtain the light body of the pearls and increase the resistance of the ball and the cast iron.

Due to the characteristics of air cooling, the environmental temperature, the stacking method, the air flow and the size of the part affect the fabric and the performance of the positive fire. The Torch organization can also be used as a method of classification of alloy steel. After heating at 900 ° C according to a sample with a diameter of 25 mm, the fabric obtained by the empty cold is divided into pearl steel, glywade steel, matélin steel and austenite steel.

The receipt is to slowly heat the metal at a certain temperature, to keep enough time, then to treat a metal heat treatment process with appropriate speed of speed. The heat treatment of heating is divided into a completely receipt, incomplete and exfoliating reception. The mechanical properties of the CAPS can be tested with stretch tests, and hardness tests can be used to detect. Many steels are provided by heat treatment. To detect HRT hardness.

The purpose of the receipt is:

① Improve or eliminate various tissue defects and residual constraint caused by steel in the flow, forging, rolling and welding process to prevent the deformation part and cracking.

② soft chemicals for cutting treatment.

③ Refine cereals and improve the organization to improve the mechanical performance of parts.

④ Prepare for the final heat treatment (extinction and recovery).

Commonly used cook

① RECIPT completely. It is used to refine the thick and heated fabric that occurs after the casting, forging and welding medium and low carbon steels. Heat the part to the temperature of all the AIDABELs at the austenite temperature from 30 to 50 ° C Make the fabric of the steel thinner.

② FYCUT OF BALLION. It is used to reduce high hardness after forging tool steel and rolling steel. Heat the part towards steel starting to form the temperature above 20 to 40 ° C. After preserving heat, the body carburee in the shape of a chip in the pearl body becomes spherical after the cooling process, thus reducing the hardness.

③ While waiting for the temperature drop. It is used to reduce the high hardness of alloy structure steels with a higher nickel and chrome content for cutting. Generally, it is cooled to the most unstable temperature of austenite at a faster speed.

④ Crystallize the receipt. It is used to eliminate the phenomenon of hardening from the metal wiring, thin plates in the process of cold traction and cold rolling (increasing hardness and decreased plasticity). The heating temperature is generally 50 to 150 ° C below the temperature of the steel to form the temperature of the austenite.

⑤ Graphite reception. It is used to transform the melting containing a large quantity of carbon in metastic canine with good plasticity. The process operation is to heat the flow at around 950 ° C after preservation of heat, it is well cooled to make the fuel body decompose to form a graphite swing.

⑥ Display reception. Used to uniformly manufacture the chemical composition of the alloy flow and improve its use performance. The method is to heat the flow as high as possible without melt, and stay warm for a long time.

⑦ Remove the receipt of stress. It is used to eliminate the internal constraint of steel molded parts and welded parts. Once the steel products are heated, starting 100 ～ 200 ° C under the temperature of the Austeen, which can be eliminated in air after insulation in the air to eliminate the internal stress.

Extinction, a heat treatment process of metal and glass. Heat alloy products or glass to a certain temperature, then quickly cool in water, oil or air, which is generally used to improve the hardness and strength of the alloy. His name is “diving fire”. The quenching part is heated to the appropriate temperature below the lower critical temperature, and the metallic thermal treatment of cooling metal in air or water, oil and other environments after preserving the heat. The steel part has the following characteristics after the caliber:

① organized the unbalanced (unstable) tissue such as martensitis, obstetrics and residual austenitic.

② There is a great internal stress.

③ Mechanical performance cannot meet the requirements. Therefore, the steel part must be recovered after the extinction.

Recovery function

① Improve the stability of the tissues, so that the change in the organization no longer occurs during use, so the geometric size and the performance of the part are stable.

② Eliminate the internal constraint to improve room performance and stabilize the geometric size of the room.

③ Adjust the mechanical performance of steel to meet the requirements of use.

The reason why recovery has these effects is that when the temperature increases, the atomic activity capacity is improved and the iron, carbon atoms and other steel alloy elements can spread quickly to obtain rearrangement And the combination of atoms, in order to make it is unstable that the unbalanced organization has gradually transformed into a stable balanced organization. The elimination of internal constraint is also linked to the decrease in metal resistance when the temperature is high. Generally, when steel is recovered, hardness and resistance decrease and plasticity is improved. The higher the temperature of the fire, the higher the changes in these mechanical properties. Some alloy steels with higher alloy elements have a high grain metal compound when they are ignited at a certain temperature range to increase resistance and hardness. This phenomenon is called secondary sclerosis.

Requirements of requirements: Different parts must be returned to different temperatures to meet the requirements used.

① The knife, the bearings, the carburetwood and the surface soaking parts are generally recovered at low temperature less than 250 ° C. After recovery at low temperature, the hardness changes considerably, the internal stress decreases and the tenacity is slightly improved.

② The spring is warmed at 350 ～ 500 ℃, which can obtain higher elasticity and necessary tenacity.

③ Middle carbon steel parts are generally recovered at 500-600 ° C to obtain good coordination of appropriate resistance and tenacity.

The high temperature extinction and recovery heat treatment process is always called quality adjustment.

When the steel has recovered about 300 ° C, it often increases its fragility. Generally, it should not be recovered from this temperature range. Certain steel of medium carbon alloy structure are easy to become crisp after high temperature recovery at high temperature. This phenomenon is called the second category of ignition fragility. The addition of molybdenum in steel or cooling in oil or water when recovered can prevent the second type of crisp. The heating of the second type of steel crisp in the fire at the original recovery temperature can eliminate this fragility.

Steel reception

Concept: slowly cool steel after heating and heat preservation to obtain the process of the organization of balance.

1. RECIPE completely

Process: AC3 heating or greater than 30-50 ℃ → Insulation → Cold with the furnace at 500 degrees below the ambient temperature cooled by air.

Objective: fine grains, organize uniformly, improve plastic tenacity, eliminate internal stress and facilitate mechanical treatment.

2. Wait for the temperature and find

Process: AC3 or higher heating → Insulation → Fast -Cold at the temperature of the pearl body transition → Wait for temperature stays → Transformer into P → Cold air;

Objective: Ibid. But the weather is short, easy to control and small dehydration and decarburization. (Suitable for relatively stable alloy steel and large carbon steel parts).

3. Degradation of the balloon

Concept: This is the steel carburetor process.

Subject: commonly analyzed steel and analyzed steel

Process:

(1) Wait at 20-30 degrees of warming and heating AC1 or above → heat storage → cool quickly to 20 degrees below AR1 → equal temperature → cold with the furnace at around 600 degrees → .

(2) ordinary ballistic reception heating ac1 above 20-30 degrees → insulation → cooling extremely slowly at around 600 degrees → air cooled. (Long cycle, low efficiency, not applicable).

Objective: to reduce hardness, to improve plastic tenacity and to facilitate cutting treatment.

Mechanism: the tablet or mesh carbide becomes granular (spherical)

Explanation: During the receipt and heating, the organization is not completely A, it is therefore also called incomplete reception.

4. Deving

Process: Heat at a temperature below AC1 (500-650 degrees) → Insulation → Chard-chard at racille temperature.

Objective: eliminate the internal constraint of the casting, forging, welding parts, etc., and stabilize the size of the room.

Steel recovery

Process: the steel weight of soil is newly heated to a temperature below A1, then cool (generally cooled by air) at room temperature.

Objective: eliminate the internal constraint generated by extinction, stabilize the size of the room, reduce the fragility and improve cutting performance.

Mechanical performance: with the increase in temperature, hardness and resistance have decreased and the tenacity of plasticity has increased.

1. Recovery at low temperature: 150-250 ° C, M Return, reduce internal stress and fragility, improve the tenacity of plastic and have strong resistance to hardness and abrasion. Used to make quantities, tools and bearings.

2. Reminding at medium temperature: 350-500 ° C, T to come back, has a high elasticity and a certain plasticity and hardness. Used to manufacture the spring, forging models, etc.

3. High temperature recovery: 500-650 ° C, S of the back, have good complete mechanical properties. Used to make gears, vilellers, etc.