Tempering And Heat Treatment Furnace Vertical Pit Type

vertical pit-type tempering furnace

Brief Introduction

• Use

The vertical pit-type tempering furnace is a periodic working furnace, with the rated heating power of 24KW and the maximum operating temperature of 650℃. Used for tempering, annealing, etc. of the metal parts or other objects.

• Structure introduction

The structure of the RJ series vertical pit-type tempering furnace is similar to the international standard pit-type furnace. The outer shell of furnace body is cylindrical, which made of the steel plate and the section steel. The inner surface of the furnace lid is made of stainless steel plate. The furnace lining is made of ultra-lightweight and energy-saving refractory bricks. The sandwich layer of the furnace lining and furnace shell is placed aluminum silicate fiber felt to keep warm, and the remaining gaps are filled and expanded with stone powder. The electric resistance wire is spirally mounted on the wire brick of the furnace hearth by OCR25A15 high resistance alloy wire. A stainless steel tempering barrel is placed inside the furnace hearth. The furnace lid is lifted and lowered by a mast. In order to uniformly heat the workpieces, a hot air circulation fan (made of a heat-resistant stainless steel shaft and a fan blade) is installed on the furnace lid, and during the heating process, the hot air is circulated up and down in the furnace to ensure uniform heating. The electric furnace is equipped with automatic temperature control cabinet and thermocouple.

• Dryoff of the electric furnace

Before using, the user should dryoff the furnace to reduce the cracking of the furnace due to rapid temperature rise during use.

100-200℃ 6-10h furnace lid open

200-300℃ 8-12h furnace lid open

300-450℃ 12-16h furnace lid close

500-600℃ 16-22 h furnace lid close

Note: The fan must be turned on at 250℃ to prevent deformation of the blades and shaft. For new or long-term re-use electric furnaces (over half a year), the user must dryoff the furnace to remove the moisture in the furnace, improve the insulation performance, and sinter the ash joint to enhance the structural strength of the furnace lining. The furnace lining after dryoff can also reduce the lining damage caused by rapid heating during use.

• Preparation before opening the furnace

1. Check the electrical control box and the furnace for dangerous things that can cause power leakage and take it out.

2. After closing, check whether the electrical appliances and instruments in the control box are working properly, and turn on the meter switch to make it working.

• Open furnace for production

1. Set the temperature of the automatic temperature control instrument according to the process requirements.

2. Put the control cabinet "handle" in the position of automatic control, start the fan, and provide power supply to heat up.

3. The cold furnace needs to be heated up to the proper temperature, next keep warm for 2 hours and then can be loaded into the workpieces, (continuous production) , which allow continuous furnace loading.

4. When pulled out the parts of the furnace, it should be switched out and powered off, after the fan stops rotating, use the mast to lift the furnace lid.

5. Carefully load the loading basket or other fixture with the crane and place on the centerline of the furnace, take care that the loaded parts do not touch the fan.

6. Close the furnace lid so that the edge of the furnace lid overlaps in the sand sealing groove to maintain the level of the furnace lid.

7. Operate according to the process requirements.

• Precautions and maintenance

1. The maximum furnace temperature does not exceed 650℃ .

2. The loaded parts are not higher than the upper end of the loading basket.

3. Strictly forbid the wet parts are placed in the furnace.

4. Do not allow the fan to stop rotating or continue to energize and heat when abnormal sound occurs.

5. Clean the furnace hearth once a month. Remove scale cinder and other contaminants.

6. The furnace temperature is not allowed to be 400℃ , open the furnace lid to rapid cool.

7. Check the bolts on the contact line clamps every month and remove the oxide scale in time to avoid poor contact.

8. Check and calibrate the temperature control meter and thermocouple every month.

9. Lubricate the furnace lid lifting mechanism and fan bearing every month.

10. When the electrical appliance series fails, professional management must be arranged.

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