Experimental method for surface heat treatment and cold plastic deformation of titanium plate

If the sintering temperature is too high, the grain growth rate of titanium carbide will be accelerated. The final sintering temperature of titanium carbide high manganese steel bonded carbide is 1420 ℃. The titanium plate manufacturer thinks that the sintering temperature should not be too high. Even make the bonding phase into liquid phase metal loss, so that the hard phase occurs adjacent, aggregation and growth, forming the source of fragmentation. This is the reason why the bond transformation between the hard phase grains analyzed before is less.

Of course, the sintering temperature should not be too low, otherwise the alloy will be under fired. In addition to the above mentioned to control the sintering temperature and speed, the vacuum in the furnace enters the liquid phase sintering stage. It is also necessary to control the vacuum degree in the furnace during sintering, because too high vacuum degree will make a large amount of liquid metal volatilize, resulting in composition segregation. Especially in the three stages of degumming, reduction and liquid phase sintering, the heating speed of sintering is not fast.

The heating speed and holding time shall be strictly controlled. In the stage of degumming at low temperature, the pressing stress and the volatilization process of the forming agent are released. If the heating speed is fast, the forming agent will not volatilize and liquefy and turn into steam, which will cause the bursting or micro cracking of the pressing blank. In the reduction stage above 900 ℃, the pressing blank should have enough time to remove the volatiles and oxygen in the raw material powder (such as mn2fe master alloy) and enter the liquid phase sintering At the same time, it is necessary to slow down the heating rate in order to fully alloy the blank.

Under the same conditions, different components of industrial titanium plate will show different decarburization behavior. For example, Si can improve the elastic limit, strength, tempering stability and elastic reduction resistance, because different alloy elements have different effects on the activity and diffusion of carbon. However, more attention should be paid to the surface decarburization caused by Si increasing the activity of carbon and chemical potential gradient in austenite.

Titanium plate manufacturers believe that the surface strength of parts is an important factor affecting the fatigue strength. Surface heat treatment and cold plastic deformation are very effective to improve fatigue strength. Reduce fatigue crack formation. The surface decarburized layer produced by grinding off heat treatment can significantly improve the fatigue limit; the direct shot peening of the surface decarburized layer produced by not removing heat treatment can significantly improve the fatigue limit compared with the shot peening after removing decarburization, such as surface quenching, carburizing, carbonitriding, nitriding, shot peening and rolling.