Regulating HB220-270, nitriding HRC>65
The foreign titanium carbide coating is useful to improve the corrosion resistance of the screw surface, but it is reported that it is not good enough to wear resistance.
The foreign countries have adopted a series of measures to improve the abrasion resistance of screw. One way is to adopt high abrasion resistant and corrosion-resisting alloy steels. such as 34CrAlNi, 31CrMo12, etc. There is also a method of spraying Xaloy alloy on the screw surface. This Xaloy alloy has high abrasion and corrosion resistance.
Force condition of Screw rod
1 deadweight G;
2 to overcome the material resistance required torque m;
3 The axial force produced by the material pressure p.
Screw is generally due to long-term wear, screw and the gap between the barrel is too large to die out of normal extrusion, but also because of the design or improper operation of the work stress exceeded the strength of the damage to the limit of examples. Therefore, the screw should also satisfy certain strength requirements.
4 The dangerous cross-section of the screw is generally at the lowest point of the thread root diameter in the feeding section.