Appraisal Background
The gear has a high load-bearing capacity. After the gear is precision cut, it is then quenched, surface quenched or carburized and quenched to increase the hardness. However, during heat treatment, the gear will inevitably deform, so it must be ground, ground or precision cut after heat treatment to eliminate errors caused by deformation and improve the accuracy of the gear. Therefore, in the gear industry, the most concerned thing is the quality of gears, which is divided into surface quality and intrinsic quality.
Zhongke Testing can carry out material product quality appraisal services, carry out appraisal work on whether there are quality problems related to gears, issue professional and reliable inspection reports, and assist courts and enterprises in resolving product quality disputes.
Basis for appraisal
GB/T 22775-2008 Gears for timing instruments Face gear
JB/T 8853-2015 Bevel gear cylindrical gear reducer
TB/T 2989-2023 Rolling stock drive gearbox Traction gear
GB/T 28247-2012 Disc gear milling cutter
JB/T 11749-2013 Finger gear milling cutter
JB/T 6434-2010 Oil transfer gear pump
JB/T 5664-2007 Heavy duty gear Failure criteria
Authentication case
A machinery company purchased a batch of gears for use in machinery manufacturing. However, because the gears broke, the defective rate increased. In order to verify whether the gear quality is up to standard, the trial court entrusted our company to conduct technical appraisal.
The expert group asked the client for the construction process card and related technical contracts, and tested the gear samples sealed by the three parties. The following problems were found:
1. The design module of the gear is too small, and the bending stress of the tooth root is large during use, which can easily cause the gear to break;
2. The accuracy of the gear is low, which leads to poor tooth surface contact, uneven load or large vibration, and local overload of the gear, resulting in corner drop;
3. The strength of the gear material is low, and the bending strength and contact strength do not meet the relevant standards;
4. This batch of gears has quality problems and is prone to breakage, making them substandard products.
