Metal powder is an important factor which makes the quality of diamond unstable in the natural environment with its oxidation. Although the metal powder reduction process is applied, the single mass mental powders are always restored before mixing. Restored even after the powder mixture, cold, loading mode, pressing and other follow-up process, because a huge surface area of the powder, in the follow-up process there is a secondary oxidation in humid regions, this brings the secondary oxidation. The consequences are particularly evident. The reduction before the hot process is the most complete restoration and it is very necessary.
Using pre-alloy metal powder can improve blade performance. However, in order to improve the blade can be repressive, often still used in part of the ingredients in a single mass of metal powder. In hot pressing, the rise in temperature to 600-700 ° C stage to set up a holding platform, manganese powder in order to achieve a single quality between the pre-alloy powder effect. As the holding time is short, between the pre-alloyed elemental powder effect is not very significant. Before the hot pressing sintering, the degree of pre-alloyed is important and it is very necessary to remain a high degree.
Usually cold head temperature reduction process. The process uses a "hot head reduction furnace," Segment reduction temperature for the sintering temperature of 85-90% (example: If the sintering temperature of 800 ° C of the cutter head, with the reduction temperature 700 ° C), high temperature Section 90-120 minutes restore time, the specific length of time to restore, to head the same color inside and outside the standard to determine.
Head after reduction at high temperatures, the following significant changes:1 full decarbonization, sintering without smoke, and improve the head of the density, improve the working environment. 2 heads snapping observation, the same color inside and outside, to restore it completely. 3 snapping is very strenuous, 50 cm height of fall is not broken, the intensity increases, there is a clear pre-alloy effect. 4 the natural environment at room temperature for 3 days, boron powder and the newly restored head comparison, no significant change in visual color, may be inferred that the oxidation resistance has greatly improved, but also verified the effect of a pre-alloy. 5 after sintering was found with the roller deburring, former head only 2 hours, and now takes 10 hours to achieve the same effect, indicating the head of the alloying and strength have greatly improved. 6 After the sintering temperature reduction of the head and not compared to an average of 8 degrees hardness.
Blade push the boat to restore the tunnel-type furnace, every 30-40 minutes into a boat, each boat can hold 400-500 head cold tablets, the daily output of about 15,000. Use of pure hydrogen, hydrogen outlet with automatic ignition device, not smoke (smokes in the combustion of carbon). Both ends of the valve for the exposure increases, the explosion will not occur, it is absolutely safe equipment. A bottle of hydrogen can be used 24-36 hours.
After high-temperature reduction of the head, the performance is quite stable. Done for five consecutive months tracking test sample cutting, each batch of the same ingredients of saw blade performance is very stable, almost no difference.
The cutter head which is adjusted slightly can have significant differences in the cutting test. This is because the factors have been ruled out after the formula to make small adjustments, blade performance will reflect the appropriate changes.
In the comparing cutting test, segment with the restore process is much sharper and can live longer than the segment without the restore process. Comparison test increase the rates of 30% and 55%. Comparison of experimental results are: (head size 40x3.2x8, saw blade diameter 350 mm, spindle speed 2850 rev / min)
In the manufacturing process of sintered diamond blade, the problem of metal oxide powder should be concerned and solved. The same formula segment appears the phenomenon with inconsistent quality, and then the powder-oxidation is the main reason. After the reduction process using cold heads, excluding natural environmental factors, the metal powder has been completely restored, and also had a pre-alloy effect is to stabilize and improve the product quality guarantee. After high temperature reduction process a wide range of applications, will make China the metal-bonded diamond products quality greatly improved.Source:http://www.mhcmp.com