Forging induction furnace heating furnace and the common energy economically heating oil furnace
In the forging production of a certain factory, the hot blank provided by the precision forging machine was originally heated in an oil-burning trolley-type heating furnace . In order to improve the quality of the product and save energy, the reciprocating induction heating furnace for forging was used to heat it. Now take this as an example to make an economic comparison between the induction furnace heating and the oil furnace heating of the blank.
The material of the blank is alloy steel. After machining, it is a hollow tubular blank. Its outer diameter is Φ 320 —— Φ 580mm and other 5 specifications and sizes, and the heating temperature is 1080 —— 1150 dragons. The precision forging machine has higher requirements for the heating quality of the hollow blank. The thickness of the outer circle oxide scale is less than 2mm, the thickness of the inner hole oxide scale is less than 1 mm, the radial temperature difference of the blank is not more than 30 ℃ , and the axial temperature difference is less than 90 dragons. The original oil-burning trolley-type heating furnace has a bottom area of 3mx7m=21m 2 , and the induction heating furnace for reciprocating forging was later changed to a power of 900 -1000kW o
1. Quality of forgings
The temperature uniformity of the blank after being heated by the induction heating furnace for reciprocating forging is good. After multiple measurements, the blank has a radial temperature difference of W30 ℃ and an axial temperature difference of W90 ℃ before being discharged , which meets the requirements of the precision forging machine for heating the blank. To [Phi] 331 mm blank, for example, by reciprocating forging induction furnace after heating the forging of forgings which pass rate of 93. 2% after heating furnace carriage forging the forging, which pass rate Is 50%.
2. Comparison of energy consumption
Reciprocating forging induction furnace heating [Phi] 331 mm blank, an average power consumption of 671kW • h / member, industrial electricity price of 0.8 membered / (kW • h), electricity heating takes for a blank 537 Yuan. Using a trolley-type heating furnace to heat a blank of ©331mm consumes 0.54t of light diesel. The price of light diesel is 5000 yuan /t, and the fuel cost for heating a blank is 2700 yuan. Heating a blank with a reciprocating induction heating furnace costs 2163 yuan less in energy costs than heating a blank with a trolley-type heating furnace.
3. The oxidation problem of the blank
Since the induction heating furnace rate faster heating time is short, small scale blank, still © 331mm heated blank example, the heating time was 70min, field-measured oxide scale thickness of the blank, the outer circle is 0.1 —— 0.3mm, the inner hole is 0.05 —— 0.1mm, accounting for about 0.2 % to 0.4% of the quality of the blank . Trolley blank heating furnace, heating © 331mm blank heating time is 10H, the scale thickness of the blank. 1 - 3mm, . 1% by mass of the blank about - . 3% O
After the Φ 331mm blank is heated by an induction heating furnace for reciprocating forging , its oxide scale thickness is calculated as 0.225mm , and the burning loss is 2.74kg . The price of alloy steel is 5000 yuan /t, and the blank is used for reciprocating power frequency forging. The burning loss of the metal heated by the induction heating furnace is 13.7 yuan. © 331mm after the blank is heated by the furnace carriage, the scale thickness by 167mm calculation, the amount of burning 20.4kg, burning the metal loss was 102 million. A guard 31mm blank by reciprocating forging induction furnace burning loss after heating a metal material than the metal material heating furnace carriage burning little loss 88. 3 yuan.
4. Equipment depreciation and overhaul costs
The precision forging machine operates in two shifts a day, and based on the production of 24 pieces of ©331mm blanks per shift , it can produce 48 pieces a day.
There are 4 induction heating furnaces for reciprocating forging , each induction heating furnace for reciprocating forging can heat 6 blanks per shift , and 4 induction heating furnaces for reciprocating forging can heat 48 blanks in two shifts to meet the requirements of precision forging machines. Production requirements.
With 3mx7m carriage type heating furnace, each furnace installed [Phi] 331 mm blank 12, each furnace heating, forging and auxiliary time totaling 14H, a first forging furnace after the furnace was heated for an Replacing 10. 5h, to meet the forging machine To produce 48 blanks in two shifts, 4 trolley-type heating furnaces must be equipped.
The investment of 4 reciprocating forging induction heating furnaces is about 12 million yuan, the investment of 4 trolley-type heating furnaces is about 3.84 million yuan, and the oil supply system supporting the trolley-type heating furnace investment is about 4.14 million yuan (in terms of 1.5 million yuan). ), if the heating year 2000 [Phi 331 mm blank, equipment depreciation and overhaul costs calculated on a consolidated depreciation rate of 6.47%, the cost of heating this one [Phi 331 mm blank reciprocating forging induction furnace is higher than with a car-type furnace [1200 - (384 +150) ] XLO . 4 . X0 0647 X total element / member . = 215 5 yuan / piece
5. Management fees and labor wages
Since the trolley-type heating furnace has an oil supply system, the inner hole of the blank needs to be blocked before heating. Therefore, the heating of the blank with the trolley-type heating furnace requires additional labor, management, and material costs. The total cost is 150 for each blank. Meta calculation.
Reciprocating forging induction furnace heating a [Phi 331 mm blanks costs
537 yuan + 13.7 membered +215. 5 yuan = 766. 2 membered
Car-heating furnace with a [Phi 331 mm blanks costs
2700 yuan + 102 yuan + 150 yuan = 2952 yuan
Annual production of 2000 [Phi] 331 mm rough calculation, reciprocating forging induction furnace heating the blank to blank cost than the heating with a heating furnace carriage
(2952 -766. 2) element / member x2000 member = 4,371,600 yuan
Only the economic analysis of the cost is carried out here. It should also be seen that the heating of the blanks with the induction heating furnace for reciprocating forging has an effect on the improvement of the workshop environment, because when heating with the oil-fired trolley heating furnace, the heat dissipated in the workshop is very large. , Especially when the trolley pulls out a large amount of heat when loading and unloading outside the furnace, which worsens the working conditions of the workers.