01 Requirements for precise Carburizing Heat treatment. cnc machining companies in china
1) Precision heat treatment of gears includes the microstructure, hardness, depth of effective hardening layer, residual stress and the quality dispersion of tooth shape and tooth direction.
2) basic conditions for precision heat treatment of gears
(1) homogeneity of materials. It is required that the materials have good homogeneity of composition and structure, that is, the consistency of hardenability of materials. The fluctuation of hardenability of materials will inevitably lead to the microstructure after heat treatment. The composition uniformity of advanced metallurgical steel has strict internal control index, and the composition homogeneity expressed by carbon equivalent can reach ±0.01 and 0.02%. cnc machining companies in china
(2) well distributed temperature field and fluid field (including Carburizing, nitriding, carburizing flow field and quenched liquid fluid field).
Precision control requirements of 02 precision Carburizing heat treatment
1). Temperature control precision GB/T. 9452 puts forward different requirements for the maximum deviation between the temperature control accuracy and the temperature in the furnace according to six types of reheating furnaces. The general heating furnaces with final heat treatment should meet the requirements of class Ⅰ ~ Ⅲ. That is, the maximum allowable deviation from the furnace temperature is ±3 ℃, ±5 ℃ and ±10 ℃, the corresponding control accuracy is ±1.0, ±1.5 and ±5.0, and the precision grade of the corresponding instrument is not less than 0. 250.3 and 0.5.
2) Carburizing atmosphere control accuracy
Using the oxygen probe as a sensor, various types of carbon control instruments and suitable for various steel products, different Carburizing process database and process software can be realized in the process of instant control. The carbon content on the surface of steel can be controlled in the range of ±0.03 ~ ±0. 05%, and the depth of permeation layer can be controlled in the range of ±0.1 mm. cnc machining companies in china
Precision Carburizing Heat treatment Technology
1) the control precision is required. The precision of furnace temperature control is ≤ ±1 ℃, the multi-point of effective heating region is ≤ ±5 ℃, the carbon potential of carburized furnace gas is controlled at ≤ ±0.05 and the depth of carburized layer fluctuates ±0.1 mm. The furnace temperature uniformity and effective heating zone are measured by GB/T 9452 at least twice a year under continuous production conditions.
2) On-line quality control. The accurate and sensitive sensing control system can be used to control the quality of heat-treated workpiece precisely and on-line, so that the qualified rate of 100% can be achieved. cnc machining companies in china