GB/T 11433-1989 Dimensions of tubes, needles and cylindrical cores made of magnetic oxides GB/T11433-1989 Standard download decompression password: www.bzxz.net

National Standard of the People's Republic of China
Dimensions of tubes, pins and rods of ferromagaetic oxides
This standard is equivalent to the dimensions of tubes, pins and rods made of ferromagaetic oxides IE220. 1 Scope and purpose
GB 11433-89
LEC 220
This standard gives information on tubes, pins and rods with a maximum outer diameter of 25 mm (1 in) and a circular cross section. Circular antenna rods and fan antenna rods form a separate standard. 2 Diameter
2.1 Outer diameter
Tubes, pins and rods may be centerless ground or not. For cores that are not centerlessly ground, the tolerance is about ±5% for an outer diameter of about 1 mm (0.04 in) and ±3% for an outer diameter of 10 mm (0.4 in) and above.
For centerless ground cores, the total tolerance for the outside diameter is usually 0.05 mm (0.002 in). Tighter tolerances can be obtained, but additional measurements must be made during the manufacturing process.
2.2 Inside diameter and wall thickness
The inside diameter tolerance is approximately +10% with a minimum value of +0.2 mm to +0.3 mm (0.008 in to +0.012 in). The wall thickness of the core, at its thinnest point, should not be less than 0.2 times the nominal outside diameter. Due to the eccentricity (see 2.3), the inside diameter should not exceed 0.6 times the outside diameter.
The gauge is used to check the eccentricity of the end of the tubular core and the comprehensive deformation caused by the change in size. The dimensions of the gauge are as follows: Note: The other blades of the tubular core should be checked at the specified values. Alternative maximum outer diameter
minimum inner diameter
3 Length
3.1 Centerless ground cores www.bzxz.net
Approved by the Ministry of Machinery and Electronics Industry of the People's Republic of China on March 2, 1989 and implemented on March 1, 1990
GB 11433--89
The length of centerless ground tube, needle and column cores should be between 2 and 10 times the outer diameter. 3.2 Cores cut before firing
The length tolerance of molded cores and extruded cores cut before firing is about ±3% of the length. 3.3 Cores cut after firing
The length tolerance of cores cut after firing can be reduced to ±0.1mm (±0.004in). Attention must be paid to the angle of the core end faces, which can cause the difference in length measured on two opposite sides to reach 10% of the outer diameter. 4 Curvature
4.1 Curvature value
The curvature is expressed in meters by the maximum deviation of a straight line through the center of the end face. For cores not exceeding 45 mm (1.8 in) in length, the curvature is not greater than 0.2 mm (0.008 in) and is independent of the length. For longer cores not exceeding 80 mm (3.1 in) in length, the maximum curvature corresponds to a circle with a radius of 1250 mm (50 in) and is proportional to the square of the length. For cores longer than 80 mm (3.1 in) the curvature has different directions and is therefore independent of the length. The total curvature of longer cores may be slightly greater than the curvature allowed by the gauge specified in 4.2 for cores longer than 80 mm (3.1 in), but this deviation is usually negligible.
4.2 Gauge for checking curvature
A tubular gauge can be used to check the curvature of the magnetic core. The dimensions of the gauge are as follows: Gauge
Sample length
45 mm(1.8 in)
45~80mm51.8~3.）
≥80 mm(3. lin)
Additional notes:
This standard was drafted by Shanghai Magnetic Material Factory. Length tolerance
±0.05 mm(0.002 0in)
45 mm(1.771 7in)
Sample length
80 mm(3.149 6in)
Inner diameter tolerance
±0.01 mm(0.000 4in)
d maximum value 0.2 mm(0.007 9in)
maximum value + (
a maximum value +0.64 mm(0.025in)
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