The Rebar Threading Machine heat treatment process includes matrix strengthening and strengthening and surface strengthening treatment.
(1) matrix strengthening and toughening, is to improve the strength and toughness of the matrix to reduce the fracture and deformation, so its conventional heat treatment must be strictly according to the process.
(2) surface strengthening treatment, the main purpose is to improve the wear resistance of the Rebar Threading Machine surface, corrosion resistance and lubrication performance. Surface strengthening treatment methods are many, mainly carburizing, nitriding, sulfur deposition, boronizing, nitrocarburizing, infiltration of metal and so on.
The use of different surface strengthening treatment process, the Rebar Threading Machine can increase the service life several times or even several times in recent years there have been some surface strengthening process, such as the following three processes:
1. ion nitriding
In order to improve the resistance of the Rebar Threading Machine, wear resistance, thermal fatigue and anti-adhesion properties, can be used ion nitriding.
The advantage of ion nitriding is to significantly shorten the time of nitriding. It can reduce the surface brittleness of the nitrided layer by the regulation of different gas components. The deformation is small and the hardness distribution curve is smooth and the flaking And thermal fatigue. It is difficult to obtain uniform heating and uniform infiltration layer, and the layer is shallow, the transition layer is steep, Temperature measurement and temperature uniformity remains to be resolved.
Ion nitriding temperature to 450-520 ℃ is appropriate, after treatment 6-9h, the nitriding layer depth of about 0.2-0.3mm. The temperature is too low, the layer is too thin; the temperature is too high, the surface prone to loose layer, reduce anti-sticking ability. Ion nitriding layer thickness of 0.2-0.3mm it is appropriate. After the wear of the ion nitriding Rebar Threading Machine, after repair and re-ionizing nitriding, can be put into use, which can greatly improve the overall life of the Rebar Threading Machine.
Nitriding process temperature is low (560 ~ 570 ℃), the deformation is small, the treated Rebar Threading Machine steel surface hardness up to 900-1000HV, good wear resistance, corrosion resistance, high temperature hardness, available In the die-casting mold, cold heading die, cold extrusion die, hot extrusion die, high-speed forging die and plastic mold, respectively, to improve the service life of 1-9 times. But gas nitrocarburizing often deformed, the expansion of the compound thickness of about 25%, not suitable for precision Rebar Threading Machine. It must be annealed and eliminated before treatment.
For example: Cr12MoV steel plate spring hole punching die, by gas nitrocarburizing and salt bath vanadium treatment, the Rebar Threading Machine life can be increased by 3 times. Another example: 60Si2 steel cold heading screw punch, the use of pre-nitriding, short-term carbon and nitrogen infiltration, direct quenching oil, low temperature quenching and high temperature tempering treatment process can improve the heart toughness, improve the cold heading punch life More than 2 times.
3. Carbon-boron-boron ternary seepage
Ternary permeation can be carried out in the nitriding furnace, the infiltration agent is boron-containing organic penetrant and ammonia, the ratio is 1: 7, the permeation temperature is 600 ℃, the permeation time is 4h, the thickness of the compound layer is 3- 4 μm, the diffusion layer depth is 0.23 mm, and the surface hardness is HV011050. The service life of the Rebar Threading Machine was significantly improved after the penetration treatment.