The high-precision tube rolling mill is mainly used to reduce the diameter of the heating elements after filling the powder, and increase the density of the magnesium oxide powder (MgO) which is inside of the heater. The tube rolling mill generally have 8 groups, 12 groups, and 16 groups of structures, and the diameter is gradually reduced by rolling. It has high efficiency and strong stability. It has its own straightening device, and the heating coil is evenly stretched within the element. For different tube diameters, it is necessary to change the rollers.
Hot runner heater (round or square)
Oval electric heater
Double-layer copper tubes, etc.
Reducing rolling mills are specially designed to reduce round, metal sheathed tubular elements. They contain a number of pairs of driven rolls, mounted in a V-shaped bearing box assembly.
Sintered carbide rolls(Cr12,W18Cr4V) are recommended for annual production more than one million meters of hard material. The life can be 5~10 times than tool steel.
12 stations can process thicker tubes and higher reduction rates than 8 stations.
The min. length of tube:110mm
Tube diameter after compressing: Φ5.2mm～Φ19.0mm
The max. diameter before compressing: 21mm
After compressing, the straightness can reach 1:300, and the roundness can reach 0.07mm.
The minimum safety distance between tubes should be 500mm, or one third of the element length.
Construction of Reducing rolling mills
Machine stand with motors and gear boxes
Bearing box assembled with rolls(high speed steel or tungsten carbide)
Simple type of straightening device
Rolling mill for Double layers of cooper tube
Twelve groups of rolling mill, a single motor is decelerated through a cylindrical gear box，to transmit the power to the roller shaft through the cross drive shaft，which drives the roll wheel to rotate，then each group completes the cold extrusion. The power of a single group of motors is 1.1Kw.
The roller is made of Cr12MoV, heat treatment hardness HRC60∽62.
The roller shaft is made of 40Cr alloy structural steel, which has been quenched and tempered by high frequency. The hardness of bearing mating surface and roller mounting surface is HRC58∽60.
Needle bearing ⅠKOBR223020, plane bearing 51108.
Rolling roundness tolerance ±0.03mm, straightness tolerance 1000mm, bending less than 0.5mm, no rotten head bending.
The total power is 13.2Kw.
Dimensions: length 1900x width 1800x1200mm, entrance center height 930mm, weight about 3000KG.
Triphase 380V 50Hz 6.10KW
Triphase 380V 50Hz 9.3KW
Triphase 380V 50Hz 12.3KW
Number of rollers
diameter reduction rate
Video： Reducing Rolling Mill-tubular heater SG01-8
Video： Reducing Rolling Mill-mini tubular - round to square 3.3x3.3mm
Video： Reducing Rolling Mill-cartridge heater
Video： Reducing Rolling Mill - round to square （9.5~7.8*7.8mm）