How to choose the current frequency when the induction heating furnace heats the steel pipe ?

Induction heating furnace heating steel pipe is generally through heat, therefore, when selecting the frequency, the hot state current D heat should be greater than the thickness of the pipe wall .

Table 2 – . 8 shows the solenoid induction heating steel pipe and steel optimal frequency, and Table 2.9 lists (above the Curie point) heating the steel pipe wall thickness to obtain the best highest efficiency when various frequencies.

Table 2-8 The best frequency when the spiral tube inductor heats the steel pipe and the steel pipe

Tube outer diameter /mm	Wall thickness/ mm	Best frequency /kHz
Tube outer diameter /mm	Wall thickness/ mm	20 ℃	800 ℃	1200 ℃
Non-magnetic steel
12. 7	1	51	85	92
	2	28	47	50
	3	21	34	37
25.4	1	25	41	44
	2	13	21	23
	3	8.9	15	16
	5	5.9	9. 8	11
50. The 8	1	12	20	22
	2	6. 1	10. 1	11
	3	4.2	6.9	7.5
	5	2.6	4. 3	4.7
76.2	1	7.9	13.2	14.3
	2	4	6.7	7.2
	3	2.7	4.5	4.9
	5	1.7	2. 8	3
102	1	5.9	9.9	10.6
	2	3	5	5.4
	3	2	3.4	3.6
	5	1.2	2. 1	2.2
12.7		1.33	3.7	6. 3
		0. 73	2	3.4
		0. 54	1.5	2.5

Table 2-9 The best wall thickness for steel pipe heating to obtain the highest efficiency at various frequencies (when higher than the Curie point)

Frequency /Hz	Diameter /mm
Frequency /Hz	5	10	20	50	100	200	300	500	10000	20000
50							25	15	7	3
150						25	10	5	2.1	1
500					20	5	2.5	1.5	0.75	0.3
1000					10	4	1.3	0.7	0.4	0. 15
2400				10	3	1.5	0.6	0. 3	0. 13
4000				5	2	0.8	0.3	0. 18	0. 07
10000			5	1.8	0.7	0. 35	0. 13	0. 08
70000		2	0.6	0.21	0. 11
440000	0.6	0.2	0. 09