感應加熱爐淬火冷卻裝置的設計要點(diǎn)

為了保證感應加熱爐淬火冷卻器的冷卻能力和冷卻效果，在設計淬火冷卻 器時(shí)要注意下列幾點(diǎn)。

1、準確計算冷卻器的冷卻能力冷卻能力就是單位時(shí)間由冷 卻介質(zhì)吸收并排放的熱能（MJ・h）。冷卻能力要大于鋼材淬火降 溫所排出的熱能。冷卻介質(zhì)帶走的熱能與鋼材釋放出的熱能之比例 大小，表示淬火冷卻器的冷卻能力。

2、淬火冷卻介質(zhì)應具有足夠的壓強冷卻介質(zhì)的壓強是提供 給介質(zhì)噴射液柱流動(dòng)能的基礎。液柱流有足夠的動(dòng)能才能沖破氣 膜，保持高的冷卻速度。冷卻介質(zhì)的壓強隨淬火鋼材尺寸的增大而 升高。直徑在100mrn以下的管材和直徑在60mm以下的棒材，淬火冷卻時(shí)使用淬火介質(zhì)的壓強為0.2〜0. 5MPa；大于以上尺寸的 管材和棒材，淬火介質(zhì)的壓強可適當提高至0. 3〜0. 6MPa。釆用 多大的淬火介質(zhì)壓強要結合生產(chǎn)實(shí)際進(jìn)行調整，以上數據僅供參考。

3、噴水孔板的尺寸噴水孔板的設計合理與否，直接關(guān)系到冷卻器的冷卻效果�？装逶O計中要把握好以下兩個(gè)要點(diǎn)。

3.1進(jìn)水管的橫斷面積要大于噴水孔總面積這樣才能保持噴水注有足夠的壓強。通常進(jìn)水管的面積比出水孔總面積大10% 左右。

3.2噴水孔的直徑和孔距要合適噴水孔直徑過(guò)小容易產(chǎn)生堵塞或銹蝕，影響冷卻的均勻性�？讖竭^(guò)大孔距必然增大少水 注的沖擊點(diǎn)，也會(huì )降低冷卻的均勻性。合適的孔徑和孔淬火 鋼材的尺寸加以選定。通常情況下孔徑應控制在2〜3mm,8〜10mm,特殊情況可適當放大。

4、淬火水柱的噴著(zhù)點(diǎn)要均勻噴著(zhù)點(diǎn)是否均勻，一方面平均噴孔的分布，另一方面還取決于鉆孔的質(zhì)量，特別是孔的深度。當鋼材旋轉前進(jìn)時(shí)，可以彌補噴著(zhù)點(diǎn)不均勻造成的缺點(diǎn)。旋渦 式冷卻器和切向水柱冷卻法，其噴水口的角度應保持一致才能產(chǎn)生 強勁的旋轉渦流，強化冷卻效果。

5、防止淬火介質(zhì)和水蒸氣進(jìn)入加熱感應器一旦淬火介質(zhì)進(jìn) 入加熱感應器內，輕者影響鋼材溫度，嚴重時(shí)會(huì )使感應器匝間短路 損傷感應線(xiàn)圈。因此，必須防止淬火介質(zhì)和水蒸氣進(jìn)入加熱感應器 內。具體措施如下。

6、在感應加熱爐淬火冷卻器與感應器之間設擋水簾。擋水簾采用耐火化纖布條制成，高溫鋼材從預留孔中通過(guò)進(jìn)入淬火冷卻器。

6.1擴大淬火冷卻器的排水孔面積或設計無(wú)底冷卻器.使冷卻 水直泄入下部水箱，保持冷卻器內不積水。

6.2淬火冷卻器進(jìn)料側釆用錐形孔板，可以防止冷卻介質(zhì)溢出。

Key Points in Design of Quenching and Cooling Device of Induction Heating Furnace

In order to ensure the cooling capacity and cooling effect of the quenching cooler of the induction heating furnace, the following points should be paid attention to when designing the quenching cooler.

1. Accurately calculate the cooling capacity of the cooler. The cooling capacity is the heat energy absorbed and discharged by the cooling medium per unit time (MJ·h). The cooling capacity is greater than the heat energy discharged from the quenching and cooling of the steel. The ratio of the heat energy taken away by the cooling medium to the heat energy released by the steel indicates the cooling capacity of the quenching cooler.

2. The quenching and cooling medium should have sufficient pressure. The pressure of the cooling medium is the basis for the flow energy of the sprayed liquid column provided to the medium. The liquid column flow has enough kinetic energy to break through the gas film and maintain a high cooling rate. The pressure of the cooling medium increases as the size of the quenched steel increases. 3 For pipes with a diameter of less than 100mrn and bars with a diameter of 60mm or less, the pressure of the quenching medium used during quenching and cooling is 0.2~0. 5MPa; for pipes and bars larger than the above size, the pressure of the quenching medium can be appropriately increased to 0.3 ~0. 6MPa. The quenching medium pressure to be used should be adjusted according to the actual production. The above data is for reference only.

3. The size of the water spray orifice. Whether the design of the water spray orifice is reasonable or not is directly related to the cooling effect of the cooler. The following two points must be grasped in the design of the orifice plate.

3.1 The cross-sectional area of the water inlet pipe must be larger than the total area of the spray hole in order to maintain sufficient pressure for the spray jet. Usually the area of the inlet pipe is about 10% larger than the total area of the outlet hole.

3.2 The diameter and pitch of the spray holes should be appropriate. If the diameter of the spray holes is too small, it is easy to cause blockage or rust, which affects the uniformity of cooling. If the hole diameter is too large, the hole distance will inevitably increase the impact point of less water injection, and will also reduce the uniformity of cooling. The appropriate hole diameter and the size of the hole quenched steel are selected. Under normal circumstances, the aperture should be controlled at 2~3mm, 8~10mm, special circumstances can be appropriately enlarged.

4. The spray point of the quenching water column should be uniform. Whether the spray point is uniform, on the one hand, the average spray hole distribution, on the other hand, also depends on the quality of the drilled hole, especially the depth of the hole. When the steel rotates forward, it can make up for the shortcomings caused by uneven spraying points. In the vortex cooler and the tangential water column cooling method, the angle of the water nozzles should be the same to generate a strong swirling vortex and enhance the cooling effect.

5. Prevent the quenching medium and water vapor from entering the heating inductor. Once the quenching medium enters the heating inductor, the lighter will affect the temperature of the steel, and the severer will cause a short circuit between the inductors and damage the induction coil. Therefore, it is necessary to prevent the quenching medium and water vapor from entering the heating inductor. The specific measures are as follows.

6. A water-retaining curtain is set between the quenching cooler of the induction heating furnace and the inductor. The water-retaining curtain is made of fire-resistant chemical fiber cloth strips, and the high-temperature steel enters the quenching cooler through the reserved holes.

6.1 Expand the area of the drainage hole of the quenching cooler or design a bottomless cooler. Let the cooling water drain directly into the lower water tank to keep no water in the cooler.

6.2 A tapered orifice plate is used on the feed side of the quenching cooler to prevent the cooling medium from overflowing.