Die fabrication and die correction, Part III

摘要

The die correction shop is informed as soon as a die is ready in the production shop. The die and drawings (die design and drawing of the shape) are given to the correction shop manager. The manager fills out an information card for each particular die (drawing number and number of the die produced for the shape to be extruded). After having checked the die, he hands over the information card, drawings and die to the corrector (preferably, to one who has corrected previous dies for the same shape). The corrector contacts the press envisaged and arranges transport of the die to the press. He marks the die, indicating the time when the press crew is to put the die in the die furnace. There, the die should not remain longer than 10 hours at about 350 deg C because steel becomes softer if it is in the furnace for too long. Usually on the following day -during a planned test campaign -the die will be put in the press for the first time. Everything should be checked before beginning the campaign: billet, alloy, die holder etc. Normally the corrector should use two billets for the first time, if the flow of the emerging shape allows this. The corrector first cuts a section from each strand from the beginning of the second stroke and marks the different strands. This allows him to observe the flow. Then, he cuts a section from the centre length and also marks this unambiguously (fig. 21).