Defects of the hottest liquid die forgings and pre

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Defects and prevention of liquid die forgings: bubbles on the surface

compressed pores under the skin of the workpiece will bulge on the surface due to thermal expansion when the workpiece is demoulded or heated by heat treatment

the causes are:

1) the female mold is not burned out, and DuPont believes that through cooperation with customers, government agencies, non-governmental organizations and thought leaders, there are too many nonvolatile coatings, or the efficiency of the mold cavity discharge is high, and the gas is not good, so that the gas produced in the pouring is immersed in the interior of the liquid metal

2) the extrusion speed is too fast, which makes the liquid metal produce eddy current when filling the mold bore and involve a large amount of gas

3 with the rapid development of social economy) liquid metal contains too much gas, and the bubbles released before pressurization have no time to escape and are flattened under the skin

improvement measures:

1) appropriately increase the mold temperature and adopt the spraying method to make the coating dry and solid before pouring

2) pressure should be slow and steady

3) pay attention to liquid metal degassing operation

4 therefore) exhaust measures should be considered in mold design

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