Key points of Cr12 die steel forging operation - heat treatment
In addition to HSS forging operation point, Cr12 die steel should pay attention to the following matters:
(1) since there are many Cr12 die steels along grain boundaries and hard alloys, the forging heat effect is significant, so the eutectic temperature is low, and it is easier to overheat than high-speed steel in the forging process and overburning. For this reason, if the phenomenon of temperature rise is found in the forging operation, the hammering force should be reduced in time or the room temperature of the forging blank should be changed gradually after a short pause, and then the hammering force should be increased.
(2) Cr12 die steel is often due to poor surface quality, upsetting side crack, therefore, should be the first "riveting", billet end and middle concave thickness, when close to the height of billet (or length diameter) 1.5 times, vertical upsetting, directly to the basic level (<1.5 do not need "riveting").
(3) Cr12 steel punching is easy to crack, generally do not recommend punching, especially less than 50mm diameter hole. For large hole, if you have to punch, punch should be preheated to 200-300 ℃; Conical punch cannot too big, double punch, flush flank, answer to heat immediately, rush to another side next, because flank temperature and anvil contact drop, continue to cut easily crack.
(4) the mass number of Cr12 die steel forgings and single forgings is relatively small. Although the cross section of the die is large, it is difficult to reach the quality measure level of small die forging. In order to ensure the quality, single forging should be used for production.
(5) cold saw cutting is suitable for hot cutting, with residual burr at the end, upsetting end to form folding, then elongation and cracking fold, and the size is not easy to be accurate.
Heating time, forging process size, hammering tonnage selection, cooling standards, common and preventive defects of Cr12 die steel are the same as HSS.